New species and records of Flabellifera from the Indian Ocean (Crustacea: Peracarida: Isopoda)

In this study of flabelliferan Isopoda from the Indian Ocean, 19 species are described as new, in 11 genera and two families: family Cirolanidae, Baharilana koloura, B. lira, Cirolana aldabrensis, C. mimulus, C. somalia, C. undata, Eurydice paxilli, and Metacirolana chemola; family Sphaeromatidae, Cassidinidea clarkae, Cymodoce fuscina, C. lirella, Dynamenella alveolata, D. remex, Heterodina (new genus), H. mccaini, Oxinasphaera brucei, O. furcata, O. tetrodon, Paracilicaea stauros, and Sphaeromopsis sulcifera. Diagnoses of the genera and species are provided, and keys to the Indian Ocean species of most of the genera are provided. The material comes primarily from Aldabra Atoll, the granitic Seychelles islands, Zanzibar Island, and Phuket in Thailand. A few miscellaneous samples from the South African Museum collections, and from the International Indian Ocean Expedition carried out in the mid‐1960s are included.


Introduction
This paper is part of a series that is based on collections of material from various sites around the Indian Ocean (see Schotte 2000, 2002). The material comes mainly from Aldabra Atoll, the granitic Seychelles, Zanzibar Island, and Phuket, Thailand, along with a few samples from the South African Museum, and the International Indian Ocean Expedition. About 450 species of flabelliferan isopod species in eight families have been recorded from the Indian Ocean (see Kensley 2001). In the present paper, 19 species from two families, the Cirolanidae and Sphaeromatidae, are recorded. Each of the 11 genera involved is diagnosed, and where appropriate, keys to their constituent Indian Ocean species are provided. Distribution of the species is provided in the keys as a further aid to separation. Revisionary works are referred to in the generic synonymies.
pereonites sparsely punctate. Coxae on pereonites 2-3 quadrate; coxae 4-7 progressively more produced and acute posteriorly; all coxae with strong, entire, oblique carina. Posterior margins of pleonites 3-5 finely denticulate. Pleonite 5 with two larger submedial and four smaller lateral tubercles. Pleotelson short, extending to mid-length of uropodal exopod, broad anteriorly and abruptly tapering to narrowly rounded apex, posterior margin bearing about 35 plumose setae with two short, strong setae distally; dorsal surface with acute tubercle near anterior margin, directed posteriorly, with eight to nine small scattered tubercles nearby. Antennular peduncle articles 1 and 2 not fused, together subequal in length to article 3; flagellum with four to five articles. Antenna extending to posterior margin of pereonite 1, flagellum of 11 articles. Mandible and palp as figured. Maxilla 1 with three stout plumose setae on endopod and about 13 setae (two slender) on exopod. Maxilla 2 with eight plumose and four simple setae on endopod, and six and four simple setae on palp and exopod, respectively. Maxillipedal endite with two coupling hooks and three terminal, plumose setae.
Pereopods as figured. Penes short, broad, separate but adjacent. Pleopod 1 exopod nearly as broad as long, not operculate; endopod one-third width of exopod, setose only on distal margin. Exopods of pleopods 3-5 with indistinct suture, only partial in pleopod 5; both rami of all pleopods with fringe of plumose setae except endopod of pleopod 5. Pleopod 2 appendix masculina large, curved, uniform in width, articulating sub-basally, extending beyond endopod by one-quarter length, covered with tiny setules. Uropodal exopod half width of endopod and subequal in length; lateral margins with four tufts of setae; medial margins bearing plumose setae and three spine-like setae. Endopod bearing about eight spine-like setae and many plumose setae. Both rami with short, simple setae scattered on surface.
Female. As for male except for sexual characters.

Remarks
Like Baharilana richmondi, B. koloura shows weak transverse furrows on all pereonites. The new species is readily distinguished from all its congeners by the morphology of the pleotelson, being nearly twice as wide as long, with deeply incurving lateral margins, and having uropods that reach only to mid-length of the uropodal exopod.

Etymology
The specific name, koloura, is from the Greek ''bob-tailed'', and refers to the pleotelson.

Description
Male. Body length more than three times greatest width. Integument of pereon covered with flattened, mosaic-like granules. Cephalon rugose with anterior margin smoothly rounded, with thickened anterior ridge, dorsal interocular suture absent; dorsal surface of cephalon and pereonite 1 with several indistinct transverse ridges; anterolateral margins of cephalon produced and bearing carinae in lateral view; posterior margin with two short, lateral sutures. Pereonites 2-7 rugose, each with medial transverse ridge meeting double transverse carinae near lateral margins; posterior margins of all pereonites appearing granular. Coxae all with strong, entire oblique carinae; coxae 3-6 nearly acute apically. Pleon without ornamentation. Pleotelson with strong mid-dorsal carina; triangular in shape, apex narrowly rounded, bearing four short, spine-like setae among plumose setae. Antennular flagellum with four articles; articles 1 and 2 not fused, combined length twice that of article 3. Antennal flagellum with seven to eight articles. Frontal lamina pentagonal, not flat but with raised hump near acute apex; lateral margins upcurved and converging slightly toward base; greatest width subequal to length. Maxilla 1 and 2 and mandible as figured.
Female. As in male, excepting sexual characters.

Remarks
The new species is quite distinctive due to easily seen characters of the habitus. The cephalon and first pereonite are rugose, not the case in any other congener. The double carinae near the lateral margins of pereonites 2-7, joined dorsally by a transverse ridge, are also unique as are shape of the frontal lamina and presence of a single longitudinal carina on the pleotelson.

Etymology
The specific name is from the Latin ''lira'', a ridge or furrow, and refers to the transverse dorsal ridges found on the pereon.

Diagnosis
Pleonite 1 often concealed by pereonite 7; pleonite 5 lateral margins covered by those of pleonite 4. Pleotelson posterior margin with setae and spines. Antennular peduncle article 3 longest. Antennal peduncle articles 4-5 longest. Frontal lamina flat, about twice as long as wide; clypeus sessile. Pereopods 1-3 with anterodistal margins of ischium and merus not produced. Pleopod peduncle without lateral lobes; only endopod of pleopod 5 without setae. Appendix masculina inserted basally. Below is presented a key to 23 known species of Cirolana from the western Indian Ocean (Bruce 1994a), without implying phylogenetic relationships among them. It is based on characters of adult males. Kensley (2001) has provided a complete list of Cirolana species from the entire Indian Ocean region; to this may be added two species from Phuket, Thailand described by Bruce and Olesen (2002 The latter part of the key, pertaining to the last eight species, was adapted from a key to closely allied Indian Ocean species presented by Jones (1976), which was in turn based on a key published by Barnard (1935 Other material examined. USNM 280267, four males, six juveniles, from four stations, coral rubble and low algal turf, Picard Island, Aldabra, intertidal to 10 m.

Description
Male. Body length about three times greatest width. All somites except telson and uropods dotted with red-brown chromatophores. Cephalon with very faint interocular furrow; rostrum not overlapping frontal lamina. Coxae 4-7 with entire oblique carinae and acute posterolateral angles. Pleonites 1 and 2 in lateral view overlapped by coxa of pereonite 7. Pleonites 4 and 5 with seven to eight tiny denticles on posterior margin. Pleotelson with dense mat of setules on dorsal surface in mature males; triangular, tapering to narrowly rounded apex bearing six spine-like setules, each separated by two plumose setae. Antennular peduncle articles 1 and 2 fused but suture still visible, article 3 subequal in length to 1 and 2 combined; flagellum with 10-11 articles. Antenna extending to pereonite 4, flagellum with 25-27 articles. Frontal lamina pentagonal, maximum width about two-thirds of length, lateral margins straight, converging very slightly toward base. Maxilla 1, maxilla 2 and mandible as figured. Maxillipedal endite with two coupling hooks and three plumose setae; article 5 of palp bearing 12 fringed setae of varying lengths amongst long, simple setae. Pereopod 1, propodus with two simple, short setules on posterolateral margin; merus bearing four short, squat, wide setae on posterior margin, each bearing a short lash; ischium with very large, stout seemingly hollow seta on anterodistal margin. Pereopod 2, propodus with three flagellated setae on posterior margin; carpus bearing four robust and one slender setae at posterodistal margin; merus with six stout and two slender setae on posterior margin; ischium bearing one large and two smaller stout setae at posterolateral corner, one short and one long stiff setae at anterolateral angle. Pereopod 7, propodus with three pairs of short, double spine-like setae along anterior margin; carpus with nine serrate setae at posterolateral angle and five simple setae at anterolateral corner; merus having seven serrate setae and four simple setae at same angles; ischium with large, hollow seta, two shorter setae and one long, flagellated seta on posterolateral margin. Penes separate, elongate, about three times as long as wide, separated by about 10% of width of sternite 7.
Pleopod 1 peduncle with four coupling hooks and two plumose setae; endopod twothirds width of exopod, lateral margins straight. Pleopod 2, four coupling hooks and four plumose setae on peduncle; appendix masculina narrow, parallel-sided, extending beyond endopod by one-quarter of length, several setules set on lateral margin near acute apex. Pleopod 3 peduncle with four coupling hooks and four plumose setae, exopod suture complete. Pleopod 4 peduncle having four coupling hooks and three plumose setae, exopod suture complete. Pleopod 5 endopod lacking marginal setae, exopod with complete suture. Uropodal exopod shorter than pleotelson, lanceolate, bifid apex containing several long setae; lateral margin with five spine-like, flagellated setae and medial margin with four such setae set among numerous plumose marginal setae. Endopod with two short, spine-like lateral setae, five medial setae and bifid apex bearing long, slender setae; subequal in length to pleotelson.
Female. Similar to male except for sexual characters. Pleotelson nearly glabrous, denticles on pleonal margins lacking.

Remarks
The new species differs from its similar congener from Réunion Island, C. mascarenensis Mü ller, 1991, by details of setation of the uropods and pleotelson: e.g. eight short, spinelike, flagellated setae on the pleotelsonic apex versus six in the new species, and seven and three such setae on lateral and inner margins of the exopod versus five and four, respectively, for C. aldabrensis. In Mü ller's species the appendix masculina is relatively longer and penes are lacking; further differences can be seen in the type and number of strong setae on the pereopods, and in the lack of an overlapping rostrum. The prominent and elongate penes of C. aldabrensis represent a rare condition in the Cirolana parva complex of species.

Etymology
The species is named for the type locality.

Description
Male. Body about three times as long as greatest width. Cephalon with submarginal anterior and faint interocular sutures. Integument smooth. Pereonite 1 with single lateral suture; coxae all with entire carina, posterolateral angles of coxae 5-7 acute. Pleonite 1 visible in lateral view, not completely overlapped by coxa of pereonite 7. Pleotelson broadly rounded, armed with eight apical spine-like setae amongst plumose marginal setae. Antennular peduncle articles 1 and 2 fused; article 3, slightly shorter than articles 1 and 2 combined; flagellum of 10-11 articles. Antennal flagellum of 24 articles, extending to pereonite 4. Frontal lamina overlapped by rostrum, pentagonal, width two-thirds of length. Mandible as figured, with three long setae at junction of molar process. Maxilla 1 lateral lobe with nine stout and seven shorter, simple setules. Maxilla 2 as figured. Maxillipedal endite with two coupling hooks and four circumplumose setae.
Pereopod 1, propodus bearing large conspicuous seta at posterodistal angle; merus with five very stout, short, blunt spine-like setae on posterior margin. Pereopod 2 as figured. Pereopod 7, carpus with one and merus with two, long, stout complex setae at posterodistal angle (see enlarged view) among cluster of other fringed and simple setae. Penes lacking, vasa differentia openings inconspicuous.
Pleopod 1 with four coupling hooks and two plumose setae; endopod 73% width of exopod. Pleopod 2 with three coupling hooks and four plumose setae; appendix masculina straight, length about 28 times basal width, apex acute bearing several fine setae, extending about one-third beyond endopod. Pleopods 3 and 4 similar, peduncle of pleopod 3 with one more plumose seta; exopod sutures complete. Pleopod 5 peduncle without coupling hooks, endopod without setae. Uropodal exopod length more than three times greatest width, subequal in length to endopod; lateral margin with seven spine-like setae, apex subbifid, medial margin bearing three short spine-like setules amongst plumose setae; a few short setae scattered on surface near lateral margin. Uropodal endopod subequal in length to pleotelson; lateral margin with two (very occasionally three) short spine-like setae; apex bifid with several long plumose setae emerging; medial margin with five spine-like setae amongst long plumose setae.
Female. Similar to male except for sexual characters.

Remarks
Cirolana mimulus can be distinguished from C. aldabrensis sp. nov. described herein, by the spination of the uropods and pleotelson, e.g. in having eight apical setules on the pleotelson (versus six) and by the lack of penes. The new species is much more similar to C. mascarenensis Mü ller, 1991 but differs in subtle ways: antennal articles 1 and 2 are fused in the Seychelles species, which also has anterior and interocular furrows on the cephalon (not shown in Mü ller's drawings), a relatively shorter appendix masculina and a complex of robust setae on pereopod 7. The easiest character to use in separation is the number of stout setules on the lateral margin of the uropodal endopod: five in Mü ller's species versus two in C. mimulus.

Etymology
The specific name is from the Latin diminutive of ''mimus'' (imitator), referring to its great similarity to another Indian Ocean species, C. mascarenensis Mü ller, 1991 from Réunion Island.

Description
Body three times longer than wide. Cephalon bearing four tiny tubercles in two pairs on posterior half, posterior pair wider apart. Evenly convex dorsal interocular suture connecting posterior margins of eyes. Pereonite 1 with five to six tiny tubercles in two rows near anterior margin. Pereonites without furrows. Pleonites 3-5 with irregular number of small, low tubercles on posterior margins. Pleotelson with barely perceptible medial depression, best seen in side view; dorsal surface with scattered, tiny setules. Apex evenly rounded, armed with eight spine-like setae and plumose setae between small teeth. Antennule, article 3 of peduncle about two-thirds length of articles 1 and 2 combined; 1 and 2 not fused; flagellum of antennule with about 15 articles. Flagellum of antenna with 42 articles, extending posteriorly to pereonite 5. Frontal lamina narrowly pentagonal, sides slightly incurved, length more than twice greatest width, acute apex not overlapped by rostral process. Maxilla 1 and 2 and mandible as figured.
Pereopod 1 with four robust and one tiny blunt setules on posterior margin of merus. Pereopod 2 merus bearing five robust and one tiny spine-like setules on posterior margin. Pereopod 7 with groups of spine-like setae at distal angles of carpus and merus. Penes present, short, separated by distance equal to about 11% of width of sternite. Pleopod 1 with five coupling hooks and three fringed setae on peduncle. Pleopod 2 with slender appendix masculina arising basally, extending beyond endopod by about 10% of its length with scattered simple setae, apex narrowing to acute point; three coupling hooks and seven plumose setae on peduncle.
Uropods projecting slightly beyond pleotelsonic apex. Exopod slightly shorter than endopod, lateral margin having seven spine-like setules amongst plumose setae, medial margins with four setules, apex acute but not bifid. Endopod with two stiff setules and long plumose setae on lateral margin; medial margin with five setules plus plumose setae, apex not bifid.
Female. As for male except in sexual characters and absence of tubercles on cephalon and pereonite 1. Ovigerous females considerably larger than mature males.

Remarks
The new species appears very similar to another western Indian Ocean species, Cirolana theleceps Barnard, 1940, in having a faint mid-dorsal depression on the pleotelson and tubercles on the cephalon and first pereonite of the male. The uropods and pleotelsonic apex of C. theleceps differ considerably, both uropodal rami being more rounded apically and, as in the pleotelson, armed with very blunt, almost scallop-like teeth unlike those in C. somalia.

Etymology
The species name is a noun in apposition, taken from its type locality, Somalia.
Pereopod 1, merus with six stout, blunt setules and three more slender, bifid setae on posterior margin. Pereopod 2, merus with six stout, one bifid and three simple setules on posterior margin. Pereopod 7, posterodistal angles of merus and ischium each with two plumose setae and several long, simple spine-like setae, carpus bearing single fringed seta and eight stiff, simple setae at same angle. Penes absent; openings on sternite 7 separated by about 3% width of sternite.
Pleopod 1 endopod one-half width of exopod. Pleopod 2, appendix masculina long, slender, extending beyond apex of endopod by about 10% of length; apical one-sixth with sparse scales or setules. Pleopods 3 and 4 similar with four coupling hooks and four plumose setae on peduncles. Pleopod 5, endopod lacking setae. Uropodal peduncle, posterior margin sinuous. Uropodal endopod broadly rounded apically, bearing 11 spinelike setae interspersed with plumose setae; scattered short setae on dorsal surface. Uropodal exopod with four stiff, simple and several plumose setae on mesial margin; stiff setae lacking on lateral margin, with four to five tufts of slender setae at notches; apex entire, with long, simple setae of various lengths. Uropodal rami subequal in length, both extending beyond pleotelson by 20% of length of exopod.
Female. Similar to male, excepting sexual characteristics and having cephalon smooth, lacking tubercles.

Remarks
The scalloped border of pereonite 7 and the character and number of cephalic tubercles in the male serve to separate this species from its congeners, as well as the anteriorly produced cephalon.

Etymology
The specific name, from the Latin for ''wavy'', refers to the distinctive scalloped posterior border of pereonite 7. Note: According to Bruce (1986), the Red Sea record for E. inermis is possibly an error; this may be another species.

Description
Female. Body length about 2.5 times greatest width. Pereonites 2-6 progressively longer; pereonite 6 longer than 7. Coxae without acute angles at posterolateral corners. Pleonites of equal length. Pleotelson with dorsal depression faint; posterior margin truncate, bearing two short, blunt peg-like setae each with an accessory flagellum and separated by four long, simple setae, with additional long seta lateral to each peg-like seta. Maximum width of pleotelson 3.5 times width of posterior margin. Antennule barely reaching mid-point of eye, flagellum composed of four articles, articles 1-2 with at least two aesthestascs each. Antenna extending to mid-length of pereonite 1; flagellum of five articles. Maxilla 1 and 2 and mandible as figured. Frontal lamina broadly rounded at apex, somewhat projecting, not reaching mid-point of antennular basal article.
Male. As female but body more slender; length of antenna and antennule unknown; pleopod 2 appendix masculina arising proximal to mid-point of endopod, tapering abruptly near toothed apex; sparse, tiny setules on lateral margins. Penes short, unfused, longer than broad.

Remarks
The present species is the second of the genus to be described from the Persian Gulf, following Eurydice peraticis Jones, 1974. Eurydice paxilli differs from all congeners by the configuration of the pleotelsonic apex in having four simple setae between two small blunt spine-like setae, which are each flanked laterally by a simple seta. The five species described from Kenya by Jones, 1971, E. agilis, E. cavicaudata, E. chelifer, E. inornata, and E. longipes, have either four or no small spine-like setae at the pleotelsonic apex. Likewise, both E. arabica Jones, 1974 from the Red Sea and E. peraticis bear four such setae there.

Etymology
The specific name is the plural of paxillus (Latin for a small peg), referring to the two diagnostic small, blunt spine-like pegs on the apex of the pleotelson. Nierstrasz, 1931 Restricted synonymy. Metacirolana Nierstrasz 1931, p 147, 162;Kussakin 1979, p

Description
Ovigerous female. Body length about 2.5 times width. Cephalon with slight mid-dorsal depression anteriorly, tiny rostral process present. Pigment variable, scattered chromatophores on all somites including pleotelson. Coxae 2-7 with distinct furrows. Pleotelson posterior margin coarsely serrate, apex flanked by two notches each containing a single short, spine-like seta, and bearing 12-13 short plumose setae. Antennular flagellum with five to six articles and two aesthetascs on each of articles 3-5. Antennal flagellum reaching pereonite 3, bearing 11-12 articles. Frontal lamina columnar, pentagonal in head-on view; in ventral view appearing truncate distally, tapering basally, length 1.5 times greatest width. Mandibular palp, penultimate article bearing about six fringed and 11 simple setae; terminal article with four fringed and six simple setae. Maxilla 1 with 11 spine-like setae on the outer ramus; maxilla 2 as figured. Pereopods and pleopods 1, 3-5 as figured.
Uropods coarsely serrate, endopods subequal in length to pleotelson, exopods shorter. Exopod with two short, stout spine-like setae and simple setae on lateral margin, two such setae on mesial margin; endopod much wider, acute distally with one stout, spine-like seta and long, simple setae on lateral margin, two robust spine-like setae present on mesial margin.
Male. Pereon more slender than in female. In mature males, mid-dorsal depression on cephalon is flanked by low bosses. Appendix masculina on pleopod 2 parallel-sided, extending beyond endopod by less than one-quarter length, abruptly tapering to acute apex. Penes separate, flat, length about twice width with two simple setae between rami.

Remarks
This species closely resembles its congener from the Gulf of Aqaba, M. fishelsoni Bruce and Jones, 1978, but differs in the shape of the apex of the pleotelson (being an obtuse median angle in M. fishelsoni and lacking the two prominent spine-like setae on the apex), as well as in the numbers of setae on the maxillule and mandibular palp, far fewer in the case of the latter species. The two notches on the pleotelsonic apex and lack of sculpturing thereon immediately separate it from all other congeners in the Red Sea and western Indian Ocean.

Etymology
The specific name, from the Greek ''chemola'', a notch, refers to this feature on the pleotelsonic apex.

Diagnosis
Adult male. Body about twice as long as greatest width, widest at pereonite 5; without membrana cingulata; surface smooth or finely granular, dorsum often with nodules; margins with fringe of fine setae. Cephalon lacking rostral point, lateral margins expanded; eyes dorsal, rounded; pereonite 1 longer than pereonite 2; pereonites 2-4 progressively increasing in length, 4-7 subequal in length. Pleonite 1 indicated by two anterolateral sutures. Pleotelson anterolateral margins not reaching lateral margin of pleon or uropodal peduncle; posterior margin without groove or exit channel. Antennule peduncle dorsoventrally compressed, articles 1 and 2 not markedly flattened or expanded; article 3 longer than article 2; flagellum slightly more than twice as long as peduncle article 3. Antenna peduncle about one-half length of article 2; articles 3-5 progressively increasing in length; flagellum with four to seven articles, shorter than peduncle. Epistome prominent in dorsal view, widely separating antennal bases; flat in ventral view with mesial constriction. Mandibles with three-or four-dentate incisor, spine row of four or five serrate spine-like setae; lacinia mobilis on left mandible; molar process with serrate teeth, some indistinct ridges. Maxilla 1 with large, weakly serrate spines plus one serrate and one short spine-like seta on lateral lobe; mesial lobe with four serrate spines. Maxilla 2 lateral and middle lobes with prominent flat nodular spines, medial lobe narrow; endite subtruncate with simple and plumose spine-like setae along distal margin.
Ovigerous female. Mouthparts not metamorphosed. Brood pouch formed by two opposing ventral pockets which overlap at sternite 4.

Description
Male. Body reticulate brown-red pigment on all segments including base of uropodal endopods. Pereonites smooth. Epistome rectangular, twice as wide as long, fairly straightsided with incurving extensions posteriorly. Pleonite 7 and pleon with few scattered tubercles especially in male. Pleotelson with four very weak longitudinal carinae, not tuberculate, medial two seeming to converge at base of segment; apex of pleotelson truncate. Antennal flagellum with seven articles; antennular flagellum with three to four. Maxilla 1 and 2 and mandible as figured. Pereopod 1 having two stout fringed setae at mid-length of propodus; pereopod 2 with scattered simple setules and two robust setae on propodus. Pereopod 7 with nine very robust and two slender setae at articulation of carpus. Pleopod 1 endopod reduced in width, indented distally, margins of both rami with simple and plumose setae. Pleopod 2, appendix masculina long, slender, extending beyond endopod by one-third total length, posterior one-third with tiny setules on margins. Pleopod 3 with complete suture on endopod. Pleopods 4 and 5 as shown, few if any marginal setae present. Fused penial process more than three times longer than wide.
Ovigerous female. As for male, except sexual characters, somewhat larger in size. Internal pouches absent.

Remarks
This animal is tentatively separated from another Indian Ocean species, C. quadricarinata Pillai, 1954, which was not examined. The latter's dorsum is furnished with ''four distinct longitudinal rows of tubercles giving the animal a quadricarinate appearance''. The rows on the pleotelson of C. clarkae, which are lacking on the dorsum, are not tuberculate but very low and smooth. Based on Pillai's illustrations, C. quadricarinata bears one large biserrate seta on the propodus of pereopod 1 whereas the new species has two; pereopod 7 is much more setose marginally than in C. clarkae. These two species both possess an apically truncate pleotelson. Cassinidea monodi (Barnard, 1951), recently transferred from Dies by Bruce (1994b), also shows four low, rounded keels on the pleotelson but is distinguished by its bluntly rounded apex.

Etymology
The species is named for its collector, Janice Clark Walker, formerly of the Department of Zoology, NMNH.

Diagnosis
Cephalon, pereon and pleon lacking dorsal extensions. Pleon bearing two, long, straight parallel sutures at each side extending to postero-lateral angle. Pleotelsonic apex with marked notch bearing median tooth. Pleopods 4 and 5 with branchial pleats on endopods only. Sexual dimorphism obvious. Uropodal endopod in male thickened, not reduced, often lanceolate; exopod lamellar. Penes long, slender, separate to base. Appendix masculina arising basally and extending well beyond apex of pleopodal endopod. Ovigerous female mouthparts metamorphosed; brood pouch formed by four pairs of oostegites arising from sternites 1-4 and overlapping at midline; brood held in internal pouches. Uropodal rami in female both lamellar.

Description
Male. Cephalon and pereonites 1-4 smooth, very sparse setae. Pereonites 5-7 each with two sometimes faint rows of small tubercles, setae increasing toward lateral margins. Pleon, anterior fused segments with many long setae near lateral margins, two strong dentate projections on posterior margin of segment, and scattered tubercles mid-region. Pleotelson with tubercles of various sizes; two rows of two elongate tubercles on either side of midline, posterior pair bifid, each of pair flanked by smaller bifid tubercle, all apically setose; anterior pair covered with short, goldenbrown setae. Posterior region at midline with small knob bearing tuft of brown setae, additional tufts on either side of knob; domed boss lacking. Apex tridentate, setose, apical notch very deep; three apices toothed, rounded distally, coplanar and of equal length. Antennule with 16 articles in flagellum, articles 5-15 bearing one aesthetasc each; plumose setae on ventral margins on articles 1 and 2 of peduncle. Antenna with 13 articles in flagellum. Frontal lamina broad, narrowly rounded at apex. Maxilliped palp article 2 bearing long distal seta. Pereopod 1 with five very stout, fringed setae and a few smaller setules on inner margin of propodus, four similar large setae on carpus, three to four stout setae on merus. Pereopod 2 with a fringe of small setules interspersed with a few longer setae on propodus, and merus. Pereopod 7 with row of stout, simple setae on propodus; carpus and merus each bearing a ''comb'' of long, slender fringed setae on anterior margins. Penes tapering evenly to acute tip, length about 9.5 times  indentation on internal margin of endopod, exopod with simple setae on external margin. Pleopod 5 with short, simple distal setae on external margin, exopod with external setae on most of margin. Uropod with rami subequal, extending very slightly beyond pleotelson apex. Endopod subrectangular, latero-distal angle toothed, with single tubercle at midline, setose laterally and ventrally near base. Exopod setose laterally and ventrally, with short, dark brown setae dorsally near external margin; internal margin arcuate, tapering to acute tip.
Sub-adult male. Dorsum smooth. Posterior margin of fused segments of pleon with two submedian tubercles, each bearing a seta. Pleotelson with ridge on either side of midline, culminating in low tubercle. Apex tridentate. Uropodal rami tapering to acute apices and extending slightly beyond pleotelson.
Ovigerous female. Dorsum smooth. Pleotelson with two submedian tubercles on posterior margin of fused segments; posteriorly, two pairs of tubercles on either side of midline. Apex of pleotelson shallowly tridentate, extending slightly beyond both rami of uropod; apices of endopod truncate, exopod with small tooth apically.

Remarks
This species differs from other species placed in this genus by having three apical lobes of the pleotelson that are coplanar, relatively slender, equal in length, rounded distally but each bearing a tiny spike, and separated by deep incisions, resulting in a marked tridentate appearance. Cymodoce tribullis Harrison and Holdich, 1984, C. longistylis Miers, 1884and C. pelsarti Tattersall, 1922, Australian species, also possess three apical lobes but those in the present new species are much longer and of identical length. The maxillipedal palp, tuberculate pleon and pleotelson, and shape of the uropodal rami are characteristic of the genus, of which C. truncata Leach, 1814 is the type species. These characters are consistent with Harrison and Holdich's (1984) diagnosis of Cymodoce (s. str.). It lacks, however, the hemispherical dome just anterior to the pleotelsonic notch which is listed by Bruce (1997) as a possible apomorphy for Cymodoce s. str. The pereopods are also similar to the type species with regards to setation. The shape of the uropods and pleotelson seem somewhat similar to those of the poorly described C. aculeata Haswell, 1881 but lack of details in the description and lack of illustrations of appendages prevent further comparison. The structure of the brood pouch is consistent with that characterizing the genus (Harrison 1984).

Etymology
The specific name, from the Latin ''fuscina'', used as a noun in apposition, means ''trident'' and refers to the shape of the three-pronged pleotelsonic apex. Male. Dorsal surface of cephalon and pereonites 1-4 smooth, bearing few marginal setae.
Pereonites 5-7 each with two transverse rows of very small tubercles. Pleon with many small tubercles, some in transverse rows. Pleotelson very granulose with two large bosses, apically bifid and setose, posterior to two ridges of tubercles also bearing setae; two irregular, longitudinal rows of small tubercles between bosses; smaller bifid tubercle posterolateral to each boss. Posterior half of pleotelson with medial, large smooth domed boss; posterior margin tridentate, medial tooth raised and subtruncate, apically bifid, extending beyond lateral teeth. Antennal flagellum with 19 articles. Antennule, article 1 with single lateral plumose seta; article 2 with one simple and four plumose setae; flagellum of about 17 articles, proximal 13 of which each bearing single aesthetasc. Epistome broad with pointed apex. Maxilliped as figured. Pereopod 1, propodus, carpus and merus with fringed, stubby setae on posterior margins. Pereopod 2, short fringe of setules with few interspersed setae on posterior margin of propodus, carpus and merus; two very stout setae, one tridentate, at posterodistal margin of carpus. Pereopod 7, several strong simple setae of varying lengths on posterior margin of propodus, carpus and merus; longer setae at anterodistal margins of carpus, merus and ischium. Penes separate at base, length six times width, parallel-sided, angled at apex, with sparse setules on medial margin in proximal half; apex appearing to twist apically. Pleopod 1, peduncle with four coupling hooks; exopod subelliptical, endopod triangular in shape. Pleopod 2, peduncle with four coupling hooks; appendix masculina slender, tapering to fine tip, 1.6 times length of endopod, curving in distal one-fourth toward midline of animal; bearing short fringe of short marginal setae in proximal half. Pleopod 4, endopod pleated with notch in medial margin near apex; exopod with subterminal articulation and many simple setae along outer margin and at apex. Pleopod 5, endopod rounded apically with fringe of short setae; exopod with complete articulation distally and four spinulose bosses. Uropodal endopod parallel-sided, concave in ventral view, subtruncate apically, dorsally granular with long marginal setae; exopod tuberculate with long dorsal and marginal setae, inner margin convex with acute tip, outer margin straight. Uropodal rami subequal in length, both extending beyond median tooth of pleotelsonic apex.

Remarks
The males of this species seem to be somewhat variable in the degree of setation especially of the posterior body. The present species is very similar to C. zanzibarensis Stebbing, 1910a but distinct due to the former's longer appendix masculina and smaller and much more slender body size. The median lobe of the pleotelsonic apex also extends farther relative to the lateral lobes in the new species. It is separated from C. tribullis Harrison and Holdich, 1984, which has ''hemispheric domes'' at the ends of the pleotelsonic ridges instead of notched tubercles and possesses pads of setae on the merus and carpus. It resembles also C. longistylis Miers, 1884, which differs in having subequal teeth at the pleotelsonic apex, lacking the prominent, dentate tubercules on either side of the pleotelson midline and having relatively longer uropods, the endopod of which is curved. Similar also to C. pelsarti Tattersall, 1922, C. lirella has relatively shorter uropodal rami but much larger dentate tubercles on the pleotelson. The presence of a hemispherical dome anterior to the pleotelsonic notch is, according to Bruce, 1997, a possible apomorphy for Cymodoce s. str. Cymodoce lirella shares this character with all the four above-mentioned species.

Etymology
The specific name, from the Latin for ''small ridge'', used as a noun in apposition, refers to the two low ridges of the pleotelson.

Diagnosis
Eubranchiate with antennular peduncle article 1 not extended anteriorly as plate. Both sexes with pereon and pleon lacking dorsal processes, and with both uropodal rami lamellar, endopod greater than half length of exopod. Pereopod 1 markedly more robust than other pereopods. All pereopods with simple, not bifid secondary unguis. Exopod of pleopod 3 with or without articulation. Sexual dimorphism obvious.
Adult male. Penes long, tapering, fused at base. Appendix masculina arising from proximomedial angle of endopod of pleopod 2 and extending to or beyond apex of endopod; usually broad proximally and tapering to acute tip. Apex of pleotelson with dorsally directed foramen connected to apex by narrow slit. Ventral margins various. Uropods broader than those of female and immatures.

Description
Male. Body length five times width. Integument pitted. Posterior border of pereonite 7 and pleon appearing granular. Pleon bearing two low, pitted transverse tubercles on either side of midline. Pleotelson granulose, rugose with many small, pitted tubercles over dome. Subapical foramen elliptical, directed anterodorsally, separated from apex by slit closed most of its length. Ventral margins of pleotelson outcurved to meet in midline. Antennular peduncle, articles 1 and 2 combined slightly longer than article 1; flagellum of eight articles, extending to middle of pereonite 1. Antennal peduncle articles increasing in length from 1 to 5, flagellum with 12 articles, reaching to pereonite 3. Mouthparts typical of genus but distal molar of left mandible with broad tooth fitting into indentation in corresponding region of right mandible as in D. liochroea and D. trachydermata. Pereopod 1, two simple and one fringed setae at posterodistal margin of merus and single fringed seta each at anterodistal margins of carpus and propodus. Pereopod 2, long, prominent seta at mid-length of ischium; three long, simple and three fringed setae at posterodistal angle of merus. Pereopod 7, fringe of long setae along posterior margin of ischium; single long and four long, fringed setae at posterodistal margin of merus; six fringed, stout setae on distal margin of carpus.
Penes thickened at one-third length with setules present, tapering to acute apices. Pleopod 1, rami subequal in width and length. Pleopod 2, appendix masculina flattened basally with marginal setae, tapering to acute apex slightly more than one-fourth length beyond apex of endopod. Uropodal rami extending beyond pleotelson, broadly rounded apically with margins appearing serrate; exopods with small tubercles proximally on dorsal surface; endopods with lateral margins upcurved.

Remarks
Dynamenella alveolata is most similar to D. trachydermata Harrison and Holdlich, 1982 (locality Queensland, Australia). It is considerably larger, holotype males are 4.0 and 2.8 mm, respectively, while the allotype female of the new species is 4.0 mm versus 2.0 mm for the latter. In the males, the pleotelsonic foramina serve to distinguish the two; in D. alveolata it is narrowly elliptical, breadth three times depth, while in the other species it is nearly circular. The dome of the pleotelson of the new species (male) is much more rugose with small pitted tubercles scattered over its surface.

Etymology
The specific name, from the Latin for ''small hollow or cavity'', refers to the pleotelsonic foramen.

Description
Male. Dorsum smooth, few lateral setae, pereonites 4 and 5 granular, 3 much less so, posterior edge of pereonite 6 with coarsely irregular, brittle ridge. Scattered chromatophores, densest on pleotelson. Pleotelson: granular, two large submedian tubercles on anterior fused segments; posterior pleonite with two diverging, longitudinal rows of four tubercles each on either side of midline, anterior pair largest; numerous smaller tubercles and tiny granulations scattered on surface; margins of pleotelsonic slit meet in midline, opening into circular, rimmed, dorsally directed foramen. Antenna flagellum of nine articles; antennular flagellum bearing 11. Mandible as figured. Pereopods 1 and 2 with simple setae only; carpus of each with two stiff setae at posterolateral angle. Pereopod 7, single plumose and two simple setae at anterodistal margin. Pleopods typical of genus. Appendix masculina evenly wide, narrowly rounded at apex, extending slightly beyond endopod. Penes fused at base, length about seven times greatest width, expanded at proximal one-third of length and tapering to blunt apices. Uropodal endopod sparsely granular on dorsal surface, extending beyond apex of pleotelson by one-sixth of length, marginally dentate; exopod exceeding length of endopod, dorsally smooth, ventrally thickened submarginally, with three or more rows of teeth.
Ovigerous female. Dorsum very similar to male, tubercles and granulation less obvious; uropods much shorter and narrower, extending only slightly beyond pleotelsonic apex. Internal pouches absent.

Remarks
The new species resembles most closely its Indian Ocean congener D. savignyi (H. Milne Edwards, 1840). It is a larger species with straighter pleotelsonic margins, broader uropodal rami and a relatively shorter appendix masculina which does not taper to an acute apex. It is also closely allied with D. bullejiensis Javed and Ahmed, 1988 from the Arabian Sea. The primary differences lie in the shape and length of the appendix masculina, the size of the uropods (longer and broader in D. remex), the lack of pubescence and oblique tubercles on the pleotelson, and straight versus sinuous pleotelsonic margins in the new species.

Etymology
The specific name, from the Latin meaning ''oarsman'', refers to the paddle-like uropods.

Diagnosis
Male. Body dorsoventrally somewhat compressed, length more or less twice maximum width; with membrana cingulata; integument smooth or finely tuberculate; margins with fringe of setae. Cephalon embedded in pereonite 1; eyes dorsal. Epistome visible in dorsal view. Coxal extension on ventrum of pereonite 1 absent; pleonal tergite absent. Exopod of uropod very small, set into margin of endopod. Pleon with free lateral margins. Pleotelson triangular, apex extending slightly beyond uropod.
Pleopod 1 with endopod reduced, about half length and half width of exopod. Pleopod 2, appendix masculina short and broad. Exopod of pleopod 3 without suture; both rami of pleopods 4 and 5 lamellar or with very weak folds. Penes long, tapering and basally fused.
Female. Similar to male except in genitalia. Mouthparts not metamorphosed. Marsupium formed by two opposing pockets opening at sternite 4.

Remarks
This genus exhibits a unique mix of characters which may be found singly in other ''subfamily'' groups. It differs from Cassidinidea, which it most resembles at first glance, by having the cephalon set into the first pereonite instead of having expanded lateral margins; the penes, instead of being entirely fused, are basally fused; and the appendix masculina, instead of being long and acute, is short and broad. These characters were mentioned by Bruce (1994b), who therein stated the need for a new genus to accommodate C. mosaica Kensley and Schotte, 1987, which is herein transferred to the new genus. The morphology of the cephalon of the new genus is shared with the Leptosphaeroma group of Cassidininae (Bruce, 1994b), which possess in contrast short, unfused penes and expanded antennular peduncles. These latter two traits are also common to those species in the Cassidina group as defined by Bruce (1994b), in which however the cephalon is not set into pereonite 1. For the same reason the new genus does not fall within Bruce's Cassidinidea group and thus remains unallied within the ''subfamily'' Cassidininae. It may indeed signify a fourth such grouping. The structure of the brood pouch, however, is identical to that of Cassidinidea, i.e. formed by two opposing pockets and different from those in Leptosphaeroma and Cassidina as described by Harrison (1984).

Distribution
Species of the genus are known at present from Belize and the Persian Gulf.
The generic name is derived from the Greek ''hetero-'' (different or other), plus the suffixdina, indicating the subfamilial affinity.

Description
Male. Body oval in outline; length somewhat less than twice maximum width. Brownish pigment sparse, more visible in mature males, usually as two submedial rows on dorsum and as patch at base of pleotelson or scattered along lateral margins of pereonites. Epistome flat anteriorly with concave lateral margins and wide, tapering extensions posteriorly. Pleotelson triangular, posterolateral margins slightly sinuous, posterior apex tapering to very obtuse point. Flagella of antennule and antenna with seven articles each. Maxilla 1, maxilla 2 and mandible as pictured. Pereopod 1 with two stout, fringed setae on propodus, one on carpus and two at posterolateral angle of merus; pereopod two with two fringed setae at posterolateral corner of merus; pereopod 7 with four very stout, fringed setae on carpus only. Pleopod 1, endopod reduced, about one-fourth total area of exopod. Appendix masculina of pleopod 2 extending well beyond apex of endopod, broad, about five times as long as wide, broadly rounded at apex; not on a posteriorly directed lobe. Penes separate throughout most of length, four times longer than wide at base, rami diverging abruptly before tapering to broadly rounded apices. Exopod of uropod one-fifth length of endopod, set into margin.
Ovigerous female. As for male except in sexual characters.

Remarks
The new species differs from its Caribbean congener in the shape of the epistome and of the pleotelson, which is narrowly rounded in H. mosaica (Kensley and Schotte, 1987). In the latter, the appendix masculina is swollen basally, tapering to a narrow apex, and the long, more slender penes do not diverge distally as in the new species.

Etymology
The species is named for Dr John C. McCain, who collected it while doing fieldwork under the auspices of the University of Petroleum and Minerals in Dhahran, Saudi Arabia. Genus Oxinasphaera Bruce, 1997 Restricted synonymy. Oxinasphaera Bruce 1997, p 151.

Diagnosis
Pereonites 2-7 with one or two rows of distinct, usually acute spikes, segments 3-6 usually with two rows. Pleotelson posterior margin medially excavate, with median process set within or above indentation, occasionally entire. Antennule peduncle article 1 anteriorly with row of prominent, ventrally projecting spikes, posteriorly with two spikes or fewer. Epistome anterior margin with one or two ventrally projecting spikes or blades. Mandible incisor multicuspid; molar process medial margin strongly produced. Maxilliped, articles 3-5 with medial margins greatly elongated and finger-like; distolateral margins of articles 2- 5 provided with abundant long setae. Uropodal exopod short, one-half or less length of exopod, apex deeply bifid; endopod projecting beyond apex of pleotelson, round in section, acute at apex and often with additional abundant tubercles. Penes paired, unfused. Ovigerous female brood pouch composed of four short oostegites arising from sternites 1-4, overlapping slightly at midline; eggs held in internal pouches. The other 22 known Oxinasphaera species, known from Australia and the Indo-West Pacific, are separated in a key to species given by Bruce (1997 , 19u099S, 36u559E, 88 m, 9 August 1964.

Description
Male. Body length excluding uropods slightly more than twice maximum width; lateral margins subparallel, widest at pereonite 4. Cephalon pitted, with short, sparse setae; anterior margin with five to six tiny tubercles on either side of rostrum; rostral spike broad with slightly crenulate margin. Pereonite 1 smooth. Pereonites 2-4 each with two transverse rows of short rounded spikes, occasional intermediate nodules and granules between rows; pereonites 5-7 each with two rows of somewhat longer, more acute spikes. Pleon very granulose with posterior boss bearing two prominent posteriorly directed projections extending beyond mid-length of pleotelson. Pleotelson very granulose, sparsely setose with two submedian anteriorly directed obtuse spikes beneath pleonal projections; lateral, transverse concavities at two-thirds of pleotelson extending inward to median one-third of width; posterior margin with two submedian indentations on either side of narrowly pointed median lobe. Ventral view as figured; ventral median lobe on posterior margin with short projection anterior to apex. Antennule peduncle article 1 with four large, regular anterior spikes, single large proximoventral spike and posterior blade; several setae on articles 1 and 2; flagellum of nine articles, distal five each with single aesthetasc. Antennae articles 3-5 with long setae; flagellum with seven articles. Epistome with thick, transverse blade anteriorly; lateral lobes very granulose. Mandibles and maxilliped typical of genus.
Pereopod 1, five to six strong, fringed setae on posterior margin of propodus; carpus having two fringed setae on posterior margin; merus with single such seta on anterodistal margin. Pereopod 2, several simple setae on distal margins of propodus; carpus with four fringed spine-like setae on posterior margin of carpus. Pereopod 7 longest, with several very robust, complex tridentate setae on distal margin of carpus; merus with two long, fringed and several simple setae on posterodistal margin. Penes elongate, tapering to narrow apex, length more than 12 times width; very short stiff setules proximally at lateral margins; fewer setules on distal one-sixth of length.
Pleopod 1 peduncle with three coupling hooks, setose on outer margin; exopod with strong stiff seta proximolaterally; endopod having groove on medial margin. Pleopod 2, appendix masculina extending somewhat beyond apex of endopod, narrowing distally before inflating to bulbous tip; tiny setules medially. Uropods rough, very granulose with several setae; exopod about one-third length of endopod and deeply bifid apically; endopod with two or more medium spikes distoventrally; apex with two prominent spikes, one directed dorsally, one ventrally.

Remarks
As noted by Bruce (1997) in his monograph of the genus Oxinasphaera, all the western Indian Ocean species, all of which except O. kensleyi are described as new in the present paper, possess elongate pleonal processes. The four new species of Oxinasphaera described in this paper, all from the western Indian Ocean, appear to be related to the O. tripartita-O. kensleyi clade proposed by Bruce, having in common a posterior antennular blade and a pleotelsonic lobe overriding the apical sinus. O. brucei is distinguished by the chisel-like blade on the epistome, the formula of spikes on the antennular peduncle, and morphology of the appendix masculina. In the same monograph, Bruce discusses the characters which separate this genus from its probable sister group, Cymodoce.

Etymology
The species is named for Dr Niel L. Bruce, respected friend, colleague and authority on numerous isopod taxa.

Description
Male. Body length slightly less than twice as long as wide. Cephalon faintly tuberculate on anterior margin with prominent bifurcate spike on rostrum. Pereonite 1 unornamented. Pereonites 2 and 3 each with two rows of very low, indistinct tubercles. Pereonites 4-6 each with two rows of low rounded spikes, spikes in anterior rows larger. Pereonite 7 with anterior row of larger, conical spikes and many fewer, smaller tubercles in posterior row. Pleon very granulose with scattered setae, having two relatively short projections on posterior margin, not reaching mid-length of pleotelson; posterolateral margin of pleon produced into spike. Pleotelson very granulose with scattered setae, having pair of short protuberances ventral to each pleonal projection, posterior protuberance larger; posterior margin with produced, rounded medial lobe overlying telsonic excision, equal in length to lobes on either side. Antennule peduncle article 1 with five regular anterior spikes, single proximoventral spike, and posterior blade; flagellum of seven to eight articles, single asethetasc each on distal five articles. Antennal peduncle articles 3-5 with long setae; flagellum of about 11 articles. Epistome bearing triangular, chisel-like blade with medial notch on posterior margin. Maxilliped as figured; other mouthparts also typical of genus.
Pereopod 1 with several stiff, fringed setae on posterior margin of propodus and two on carpus. Pereopod 2 with single fringed and three simple setae at distal margin of carpus. Pereopod 7 with long stiff setae on posterior margin of propodus, carpus and merus; several long setae and two complex tridentate setae on distal margin of carpus.
Penes length about 12 times width, tapering to acute apex; spinulose on distal onefourth. Pleopod 1 with three coupling hooks; medial margin of endopod with groove. Pleopod 2, appendix masculina bulging somewhat at mid-length before tapering to narrowly rounded apex extending by one-sixth of length beyond posterior margin of endopod. Uropodal exopod about one-third length of endopod; endopodal apex with single, strong dorsally curved spine and three ventral tubercles, distalmost largest.
Ovigerous female. Dorsum smooth, unornamented, with broadly rounded pleotelsonic apex; not distinguishable from other females in genus. Brood pouch typical of genus.

Remarks
The forked epistomal blade and pattern of antennular spikes (five regular anterior and one proximoventral) separate the new species from all other western Indian Ocean species. See comments under ''Remarks'' for O. brucei.

Etymology
The specific name furcata, from the Latin for ''forked'', refers to the shape of the epistome, a diagnostic characteristic of the species.

Description
Male. Length 2.6 times width, lateral margins subparallel. Cephalon smooth. Rostral spike absent. Pereonite 1 without ornamentation, several simple setae at lateral margins. Pereonite 2 with two transverse rows of very low, conical spikes, posterior row barely visible; pereonites 3-7 with scattered setae and two transverse rows of tubercles, largest spikes on pereonite 7. Pleon very granulose with two relatively short projections posteriorly, not extending beyond apex of pleotelson; large dorsally directed spike at posterolateral angle of projection and single smaller one posterior to it; pleotelson very tuberculate with few scattered setae; posterior margin with medial projection overlying telsonic excision and ending in upwardly turned spike, equal in length to lobes on either side. Ventral view of pleotelson as figured. Antennular peduncle article 1 with seven anterior spikes, one tiny, plus one large proximoventral spike; article 2 with four plumose and several simple setae; flagellum with eight articles, terminal five with one asthetasc each and basal article bearing two plumose setae anterodistally. Antennal peduncle of five articles, increasing in length distally and all bearing long simple setae; articles 4 and 5 with one and three distal plumose setae, respectively; flagellum of 11 setae-bearing articles. Epistome with four large fang-like spikes, lateral two longer in dorsal view. Mouthparts (not figured) typical of genus.
Pereopod 1, propodus with one plumose and several long, simple setae on distal margin; carpus, single stout serrate seta on posterodistal margin and single plumose seta on anterior margin; merus, two stiff, fringed setae at anterodistal angle; ischium, grooved to accommodate merus, with patches of setules and single strong stiff seta near anterodistal margin. Pereopod 2, propodus with several strong stiff setae on posterior margin; carpus, two fringed setae on posterior margin. Pereopod 7, propodus with several long setae at distal margin; carpus bearing several very long stiff setae and two very strong, complex trident setae at posterodistal margin; ischium with a few long stiff setae on antero-and posterolateral margins. Penes elongate, length 3.5 times width at base; several scattered setules in proximal onethird; rows of very fine setules in distal one-fourth of rami; rami slender, tapering to narrowly rounded apices.
Pleopod 1, three coupling hooks on basis; exopod quadrate with single strong seta and fringe of fine setae at anterolateral corner; endopod narrower, grooved on medial margin. Pleopod 2, appendix masculina length eight times width, tapering slightly, curved at tip, apparently grooved and bearing many setae near apex; extending beyond margin of endopod by one-fourth length. Uropodal exopod very granulose, bearing many setae, about three times length of endopod; endopod bifid.

Female. Unknown.
Color. Evenly spaced brown chromatophores scattered on all segments, also on uropodal endopods.

Remarks
Oxinasphaera tetrodon can be recognized by the absence of a rostral spike and by having seven irregular spikes on antennular peduncle article 1 and four prominent spikes on the epistome.

Diagnosis
Hemibranchiate with endopod of pleopod 3 lacking branchial folds. Both sexes with cephalon, pereon and pleon lacking dorsal extensions. Pleon bearing two long, straight parallel sutures at each side; sutures extending to posterolateral angle. Pleotelsonic apex with a marked notch bearing a median tooth. Pereopods 1-3 with anterior surfaces of ischium and merus bearing, at most, several short superior spine-like setae. Sexual dimorphism obvious, especially in morphology of uropods and dorsal ornamentation of the pleotelson.

Description
Male. Pereon smooth with scattered setae, single and in pairs on dorsum, especially abundant at posterolateral margins; four tufts of setae along posterior margin of pereonite 7. Brown chromatophores spread evenly, sparsely over all segments. Pleotelson short, broad; anterior fused pleonites with two submedial projections and four bundles of setae along posterior margin; fifth pleonite bearing two large bosses on either side of midline, each with fringes of long, prominent setae; long setae numerous on lateral margins of segment; deep median notch bearing a cruciform projection, apically truncate, with many setae anteriorly and extending from apex. Antennule flagellum with 10 articles, single aesthetasc on articles 5-8 and 10, two on penultimate article. Antenna flagellum with 10 articles. Frontal lamina broad with rounded apex, transverse ledge projecting ventrally. Maxilliped as figured. Pereopod 1 with three stout, complex setae each on propodus, carpus and merus; dense setal patches near anterior margins of carpus and merus. Pereopod 2, setal patches on anterior margins of carpus and merus, proximal area of propodus and anterodistal margin of ishium. Pereopod 7 with many long, robust, fringed setae as figured on carpus; merus with three stiff, robust setae at posterolateral angle. Penes, length five times width at base. Pleopod 1 with three coupling hooks on basis, plumose setae where figured. Pleopod 2, four hooks on basis; appendix masculina extending one-fourth length beyond apex of endopod, dilating slightly near tip then constricting to narrowly rounded apex. Pleopod 3 with four hooks on basis, complete transverse suture on exopod, plumose marginal setae indicated in figure. Pleopod 4 with sparse simple setae on external margins of both rami; single strong apical seta on each ramus; subterminal indentation on endopod. Pleopod 5 exopod with four distinct patches of dentate spinules, one patch anterior to articulation; sparse setae on internal margin. Uropod with endopod short, extending to length of pleotelsonic apex, with rounded median extension; exopod tuberculate, setose and twice length of endopod, inner margin convex anteriorly; exopod and endopod ventrally tuberculate. Ovigerous female. Pleotelson with boss on either side of midline, few setae, apex truncate with marginal setae. Uropodal rami of equal length, both shorter than pleotelsonic apex; endopod broadly rounded apically and wider than exopod. Brood pouch with anterior pair of oostegites meeting at midline, posterior three pairs overlapping.

Description
Male. Body length about twice greatest width, strongly conglobate. Cephalon smooth, or very faintly granular, wider than long, moderately convex with pointed rostrum barely visible in dorsal view; epistome narrowly rounded at apex, as broad as long, with ''arms'' extending to mid-length of labrum. Pereonites 1-6 smooth, without sculpturing or setae except few at margins. Pereonite 7 with submarginal transverse ridge underlapping margin of pereonite 6 in conglobation. Pleotelson wider than long, apex narrowly rounded, bearing in anterior half a faint medial furrow flanked by obscure ridges; with few scattered, short setae and faint tubercles over surface clearly detectable only in stained specimens.
Antennule basal article subequal in length to articles 2 and 3 together; flagellum of five articles, articles 4 and 5 each bearing single aesthetasc. Antenna with articles 1-3 short, subequal; article 4 twice length of article 3; article 5 subequal in length to 3 and 4 together; flagellum of eight setose articles. Mandible with incisor of three sclerotized cusps, spine row with five spines, two of which fringed, molar with many teeth. Maxilla 1, inner ramus with four fringed setae; outer ramus with five blunt, robust setae and four more slender stiff setae, two or three fringed. Maxilla 2, inner ramus with seven setae on distal margin; both lobes of outer ramus with four fringed stiff setae each. Maxillipedal endite broad, with single coupling hook on mesial margin, distal margin bearing three blunt and several fringed setae; palp of five setae-bearing articles, articles 2-4 each with low rounded distomesial lobe. Pereopod 1, propodus with single fringed, single dentate and several simple setae on posterodistal margin; carpus with single stout, fringed seta on posterodistal margin; merus with strong, simple anterodistal and posterodistal setae; merus and ischium with several short setae along posterior margin. Pereopod 2, single plumose seta at anterodistal margin of propodus and carpus; merus with single stiff, fringed seta at anterodistal margin. Pereopod 7, one simple and one plumose seta at anterodistal margin of propodus; four stout fringed setae at distal margin of carpus; carpus and merus with many fine setae along posterior margins, merus with single strong stiff seta at anterodistal margin and several simple setae along posterior margin. Penes long, slender, fused at base, six times longer than basal width, tapering to rounded apices; patch of tiny setules near and on margin in anterior half. Pleopod 1, basis with three distomesial coupling hooks, endopod narrower and slightly shorter than exopod, latter with single stiff seta proximally. Pleopod 2, stout appendix masculina tapering slightly, extending somewhat beyond endopod, apex blunt. Pleopod 3, basis with three coupling hooks, fringe of setae on distomesial margin of endopod. Pleopod 4, both rami with transverse folds, tapering to rounded apices.
Ovigerous female. Cephalon and pereon smooth; pleotelson with very faint medial furrow and scattered setae; pereonite 7 as in male. Mouthparts and brood pouch typical of genus.

Remarks
At present six species of Sphaeromopsis are known and can be distinguished from the new species and each other by the characters of the pleotelson. S. heardi Kensley and Schotte, 1994 from the Caribbean has obvious sculpturing on the pleotelson whereas the species from Brazil, S. mourei Loyola e Silva, 1960, is completely smooth. That of S. serriguberna Holdich and Harrison, 1981, from Australia has a mid-dorsal raised area. In the three known Indian Ocean species the pleotelson varies from broadly truncate in S. amathis Holdich and Jones, 1973 (Kenya), and reticulate with sinuous margins in S. reticulata Stebbing, 1910b (Red Sea) to smooth and broadly rounded in the Pakistan species S. minutus Javed and Yousuf, 1995. The faint longitudinal, medial furrow in S. sulcifera is unique.

Etymology
The specific name is derived from the Latin sulcus, a furrow, plus -fera, bearing, and refers to the faint sulcus on the pleotelson.