Ameira zahaae Karanovic & Cho, 2012, sp. nov.

Ameira zahaae sp. nov.

(Figs. 1–4)

Type locality. South Korea, West Sea, Jangbong Island, muddy beach, intertidal zone, 37.539231°N 126.343417°E.

Specimens examined. Types only: holotype female dissected on one slide (collection number NIBRIV0000232633), and allotype male dissected on one slide (collection number NIBRIV0000232634); both collected from type locality, 12 August 2010, temperature 25.9 °C, leg. W. Lee.

Etymology. The species name is dedicated to a renowned contemporary Iraqi-British architect Ms Zaha Hadid, who is designing one of the most ambitious projects in Seoul: the Dongdaemun Design Plaza & Park. Senior author’s admiration of her work worldwide may contribute to a view of this architectural complex as an embodiment of modern Korea. The name is a noun in genitive singular.

Description. Female. Total body length, measured from tip of rostrum to posterior margin of caudal rami (excluding appendages and caudal setae), 448 μm. Preserved specimen yellowish. Nauplius eye not visible. Prosome comprising cephalothorax with completely fused first pedigerous somite, and three free pedigerous somites; urosome six-segmented, comprising fifth pedigerous somite, genital doble somite (fused genital and first abdominal somites) and three free abdominal somites. No sclerotized joint between prosome and urosome. Habitus (Fig. 1 A, B) cylindrical, gently tappering towards posterior end, not very slender, podoplean boundary between prosome and urosome inconspicuous; prosome/urosome ratio nearly 1.1 and greatest width in dorsal view at posterior end of cephalothorax. Body length/width ratio about four; cephalothorax 1.2 times as wide as genital double-somite. Free pedigerous somites without pronounced lateral or dorsal expansions, pleural plates only partly covering coxae of swimming legs in lateral view. Integument relatively strongly chitinized and without cuticular windows or pits anywhere. Surface ornamentation of somites consisting of 85 pairs and three unpaired pores and sensilla (numbered with Arabic numerals consecutively from anterior to posterior end of body, and from dorsal to ventral side in Figs. 1 A, B, 2A, B), and several rows of spinules on urosomites only. Rostrum small, membranous, linguiform with relatively sharp tip, reaching just beyond half length of first antennular segment, about twice as long as wide and not demarcated at base; ornamented with two dorsal sensilla (no. 1 in Fig. 1 A, B).

Cephalothorax (Fig. 1 A, B) almost gradually tapering towards anterior end in dorsal view, about 1.2 times as long as wide; represents 28% of total body length. Surface of cephalic shield ornamented with one pair of lateral pores (no. 14), one unpaired dorsal sensillum (no. 17), and 23 pairs of long sensilla (nos. 2–13, 15, 16, 18–26); sensilla nos. 19–26 belong to first pedigerous somite incorporated into cephalothorax. Second pedigerous somite (first free) ornamented with one pair of pores antero-laterally (no. 28), and eight pairs of long sensilla (nos. 27, 29–35); antero-dorsal pair of sensilla (no. 27) serially homologous to pair no. 19 on first pedigerous somite. Third pedigerous somite ornamented similarly to second one, only difference being additional pair of dorsal sensilla near posterior margin (no. 38). Fourth pedigerous somite ornamented with antero-dorsal pair of pores (no. 46), as in previous two somites, and seven pairs of long posterior sensilla (nos. 47–53); recognising serially homologous pairs not as easy as with two previous somites. Hyaline fringes of all prosomites braod and smooth, except on fourth pedigerous somite where fringe narrow dorsally. Fifth pedigerous somite (first urosomite) ornamented with four pairs of posterior sensilla (nos. 54–57), as well as with one pair of lateral pores (no. 58); hyaline fringe smooth and very narrow.

Genital double-somite (Figs. 1 A, B, 2A) as long as wide (ventral view); internal suture (remnant of segmental fusion) strongly sclerotised, visible dorsolaterally at midlength of somite, furnished with four parallel short rows of small spinules (two dorsal and two lateral), four pairs of sensilla (nos. 59–62), and lateral pair of cuticular pores (no. 63); posterior part of genital double-somite ornamented with two pairs of large lateral pores (nos. 64, 65), one unpaird ventral pore (no. 66), posterior row of spinules on eash side laterally, and four pairs of posterior sensilla (nos. 67–70); hyaline fringe finely serrated. Genital complex (Fig. 2 A) with single large copulatory pore, weakly sclerotized and almost stright copulatory duct, and two small ovoid seminal receptacles. Single median genital aperture covered by fused reduced sixth legs, represents 45 % of somite’s width. Third urosomite (first free abdominal somite) ornamented with posterior row of spinules (interrupted dorsally), unpaired dorsal cuticular pore (no. 71), two pairs of cuticular pores (nos. 72, 73) laterally and ventrally respectively, unpaired dorsal posterior sensillum (no. 74), and three pairs of posterior sensilla (nos. 75–77); hyaline fringe finely serrated. Fourth urosomite (preanal) ornamented with single pair of lateral cuticular pores (no. 78), and short posterior row of slender spinules ventrally; hyaline fringe finely serrated. Anal somite (Figs. 1 A, B, 2A, B) clefted medially at last third, ornamented with pair of large dorsal sensilla (no. 81), seven pairs of cuticular pores (nos. 79, 80, 82–86), ventro-lateral anterior row of slender spinules, ventro-lateral posterior row of spinules at base of each caudal ramus, and two short parallel rows of slender spinules ventrally posterior and anterior of most median cuticular pore (no. 86); anal operculum convex, narrow and short, reaching 2/3 of anal somite, represents 35% of somite's width, ornamented with numerous minute spinules near posterior margin on inner side and only slightly protruding beyond posterior margin of anal operculum; anal sinus ornamented with two parallel diagonal rows of hair-like spinules on each side, widely open, with weakly sclerotised walls, and without any chitinous projections.

Caudal rami (Figs. 1 A, B, 2A, B) short but robust, about half as long as anal somite, about 0.8 times as long as wide (ventral view), parallel and nearly cylindrical, with space between them about 0.7 times one ramus width, and with dorsal diagonal suture in anterior half; with seven elements (three lateral, one dorsal and three apical); ornamentation consists of two spinules at base of both large lateral setae, four spinules along posterior margin ventrally (at base of inner apical seta), and two pairs of pores (nos. 87, 88). Dorsal seta relatively short and slender, smooth, inserted close to postero-median corner, about 1.2 times as long as caudal ramus, triarticulate at base (i.e. inserted on two pseudojoints). Lateral setae all smooth and slender; distalmost seta longest, inserted closer to ventral side and very close to posterior margin, more than six times as long as smaller proximal seta, 1.7 times as long as larger proximal seta, and about 2.5 times as long as caudal ramus; proximal lateral setae inserted very close to each other in cuticular depressions similar to those of typical sensilla. Inner apical seta smooth, broken off on both rami but certainly longer than dorsal or any of lateral setae. Middle apical seta strongest, with breaking plane, broken off on both rami. Outer apical seta also with breaking plane and strong, broken off on both rami.

Antennula (Fig. 1 C) eight-segmented, joined to cephalotholax with small triangular pseudosegment laterally, approximately 0.9 times as long as cephalothorax, unornamented. Long aesthetasc on fourth segment very slender, fused basally with adjacent large seta, and reaching beyond tip of appendage for length of last four segments combined; slender apical aesthetasc on eighth segment fused basally with two apical setae, forming apical acrothek. Setal formula: 1.9.6.4.2.3.4.7. Only seta on first segment bipinnate and one seta on second segment unipinnate, all other setae smooth. Two lateral setae on seventh segment and four lateral setae on eighth segment biarticulatedat base (i.e. inserted on small pseudojoint); all other setae uniarticulatedand without breaking planes. Length ratio of antennular segments, from proximal end and along caudal margin, 1: 2: 1.1: 1: 0.9: 0.7: 0.4: 0.9.

Antenna (Fig. 3 E) relatively short, composed of coxa, basis, two-segmented endopod and one-segmented exopod, although basis and first endopodal segment partly fused on posterior surface. Coxa very short, unarmed and unornamented. Basis more than twice as long as coxa and about 1.2 times as long as wide, ornamented with two large spinules along inner margin distally, unarmed. First endopodal segment about 1.6 times as long as wide and nearly 1.5 times as long as basis, unornamented and unarmed. Second endopodal segment 1.5 times as long as first endopodal segment, with two surface frills subdistally, armed laterally with two spines flanking thin seta; apical armature consisting of five geniculate setae, longest one fused basally to additional smaller seta; smallest seta bearing proximal tuft of fine setules; longest seta bipinnate, others finely unipinnate; ornamentation consisting of two spinules on ventral surface basally and several long spinules at base of lateral spines. Exopod slightly longer than basis, with narrow basal part and somewhat wider distal part; ornamented with longitudinal row of spinules on anterior surface, proximalmost one exceptionally large; with one lateral (inserted at about 3/4) and two apical strong and bipinnate setae; apical setae subequal, about 1.4 times as long as lateral seta and 1.8 times as long as exopod.

Labrum (Fig. 1 B) large compared with cephalothorax, trapezoidal, rigidly sclerotized, with relatively short and somewhat concave cutting edge, ornamented subapically with two rows of six or seven strong spinules and apically with minute spinules. Not mounted in satisfactory position to allow independent drawing.

Paragnaths (Fig. 1 E) ellipsoid, about twice as long as wide, with several parallel rows of spinules of different length apically, few spinules laterally in proximal part, as well as row of four large spinules along inner margin on each lobe; lobes fused basally into medial linguiform plate, wich ornamented apically with row of hair-like spinules.

Mandibula (Fig. 2 C) with wide cutting edge on elongated coxa, with two tricuspidate strong ventral teeth, three unicuspidate strong teeth and several spinules in middle, four fine teeth (or strong spinules) in dorsal part, and single dorsal unipinnate seta. Palp uniramous, comprising basis and one-segmented endopod. Basis with inflated distal part, about 1.8 times as long as wide, with single strong and distally bipinnate inner seta, unornamented. Endopod slender and small, also unornamented, about half as long as basis and 1.3 times as long as wide; with four slender setae apically and one laterally on inner margin; all seta smooth, except outermost apical, which sparsely bipinnate.

Maxillula (Fig. 2 D) with large praecoxa; arthrite rectangular, unornamented, with two anterior surface setae, three lateral and four apical elements (probably three spines and one seta; dorsalmost of apical elements characteristically antler-like). Coxal endite much shorter than praecoxal arthrite, armed apically (on inner margin) with one curved and stout, bipinnate seta, and another smooth and slender seta. Basis significantly shorter than coxal endite, with four smooth setae apically and subapically. Endopod represented by minute segment, basally fused to basis, with single plumose slender seta apically.

Maxilla (Fig. 2 E) ornamented with row of strong spinules distally on outer margin of syncoxa. Proximal endite of syncoxa well developed although not strongly sclerotized, not highly mobile, somewhat bulbous, with smooth setae: one apically and one subapically. Distal endite of syncoxa cylindrical, well sclerotised and highly mobile, armed apically with one strong unipinnate seta, and two smooth and sleder setae; smooth setae of subequal length, about 1.6 times as long as unipinnate seta, and 2.6 times as long as endite. Basis drawn out into long claw, with shorter spiniform and curved seta at base, ornamented with minute spinules along convex margin. Endopod represented by minute segment, basally fused to basis, with two long and smooth apical setae of subequal length; enopodal setae about 1.2 times as long as basal seta, and all reaching 4/5 of basal claw.

Maxilliped (Fig. 2 F) with short and stout syncoxa, ornamented with several rows of spinules of various lengths (some very long), and with single bipinnate seta subapically. Basis about 1.9 times as long as wide and 1.4 times as long as syncoxa, unarmed, ornamented with longitudinal row of slender spinules along inner margin distally, as well as with two shorter rows of spinules on outer margin (one near midlenght, other close to distal margin).

Endopod represented by long curved claw, about as long as basis, ornamented with row of spinules along concave side distally, accompanied at base by thin smooth and short seta.

All swimming legs (Fig. 3 A, B, C, D) of similar size and length in comparison to body length, composed of small triangular and unarmed praecoxa, large rectangular and unarmed coxa, shorter and nearly pentagonal basis, slender three-segmented exopod, and also slender and three-segmented endopod; each leg joined to its pair on opposite side of body by simple quadriform intercoxal sclerite.

First swimming leg (Fig. 3 A) with smooth intercoxal sclerite, its distal margin nearly straight. Praecoxa small and triangular, ornamented with row of small spinules on anterior surface along distal margin. Coxa 1.2 times as wide as long, ornamented with cuticular pore on anterior surface close to inner margin, and with two parallel rows of long spinules along outer margin. Basis with one short but not very strong spine on outer corner (with four long spinules on its surface), and one finely bipinnate strong spine on inner distal corner; ornamented with spinules at base of each spine, as well as with distal row of spinules between exopod and endopod, short row of slender spinules on inner margin, and cuticular pore on anterior surface close to outer spine. Exopod with all segments of about same length, each about 1.6 times as long as wide and ornamented with spinules along both inner and outer margins; first two segments with single strong and finely bipinnate spine on outer distal corner; third segment with three strong and finely bipinnate spines on outer margin and two setae apically; outer apical seta geniculate and unipinnate along outer margin, inner apical seta not geniculate and bipinnate, with spinules on inner margin much longer than those on outer margin. Endopod geniculate and 1.8 times as long as exopod; first endopodal segment slightly longer than exopod and 4.4 times as long as wide, ornamented with slender spinules along inner margin and three spinules along distal margin, with single bipinnate inner seta, which about 0.7 times as long as segment; second segment smallest, about as long as wide and only 0.24 times as long as first segment, ornamented with two spinules on outer distal corner, and with single slender and bipinnate seta on inner distal corner; third segment slender, about five times as long as wide and more than twice as long as second segment, armed apically with three elements; outermost apical element probably spine, strong and 0.8 times as long as third segment, unipinnate along outer margin; middle element very strong and geniculate seta, nearly twice as long as outer element, and finely unipinnate along outer margin distally; innermost element slender bipinnate seta, slightly shorter than outer element.

Second swimming leg (Fig. 3 B) with intercoxal sclerite ornamented with two arched rows of small spinules on anterior surface, its distal margin deeply concave. Praecoxa small and triangular, ornamented with row of small spinules on anterior surface along distal margin. Coxa nearly 1.5 times as wide as long, ornamented with transverse row of minute spinules on anterior surface, and with two parallel rows of long spinules along outer margin (one on anterior and other on posterior surface). Basis with single unipinnate and short but not very strong spine on outer distal corner; ornamented with spinules at base of spine, as well as with distal row of spinules between exopod and endopod, several parallel rows of very slender spinules along inner margin, and cuticular pore on anterior surface close to outer spine. Exopod with all segments of about same width; first two segments of about same length, each almost twice as long as wide, ornamented with spinules along both inner and outer margins (those on outer margin much stronger), and with inner distall frill; first segment with single strong and finely bipinnate spine on outer distal corner; second segment with similar outer distal spine, but additionally with slender and bipinnate inner seta, about as long as segment, and additionally ornamented with cuticular pore on anterior surface near outer dista corner; third segment about 1.6 times as long as second segment, ornamented with pore near outer distal corner and spinules along outer margin, with three strong and finely bipinnate outer spines, two apical bipinnate setae, and two slender and bipinnate inner setae; outer apical seta very strong (spiniform) with spinules along outer margin much shorter than those along inner margin, about 1.5 times as long as segment, and 2.7 times as long as outer spines; inner apical seta slender, with long spinules on both sides, slightly longer than outer apical seta; distal inner seta slightly shorter than third segment and 1.5 times as long as proximal inner seta. Endopod straight (not geniculate) and 0.7 times as long as exopod; all segments of about same length, but progressively narrower from proximal to distal end, each ornamented with single pore on anterior surface close to outer distal corner, and row of strong spinules along outer margin; first two segments additionally ornamented with small frill on inner distal corner, and with single bipinnate inner seta; third segment with one inner seta, two apical setae and one subapical outermost spine; apical setae of equal length, bipinnate with slender pinules on both sides, 1.4 times as long as entire endopod, 1.6 times as long as inner seta, and nearly five times as long as outer spine; inner setae on second and third segment with short spinules along inner margin, and long spinules along outer margin.

Third swimming leg (Fig. 3 C) very similar to second swimming leg, except for slender outer seta on basis and two inner setae on third endopodal segment.

Fourth swimming leg (Fig. 3 D) similar to third swimming leg, except for ornamentation of coxa and intercoxal sclerite, length of outer basal seta (shorter on fourth leg), and armature of third exopodal segment. Intercoxal sclerite smooth, with deeply concave distal margin. Coxa 1.6 times as long as wide, ornamented with cuticular pore on anterior surface close to inner margin, and with two parallel rows of long spinules along outer margin (one on anterior, other on posterior surface). Inner spinules on basis shorter than those on second and third legs. First exopodal segment with three spinules on anterior surface, which absent on second and third legs. Third exopodal segment ornamented with two spinules on posterior surface distally, row of slender spinules on inner margin proximally, in addition to outer spinules and anterior pore; with three outer finely bipinnate spines, two apical bipinnate setae, and three inner setae; distal inner seta minute (arrowed in Fig. 3 D), midlle inner seta very strong and with comb of strong spinules on inner margin distally, while proximal inner seta slender and bipinnate; inner apical seta slender and bipinnate, 1.5 times as long as much stronger outer apical seta, and about as long as middle inner seta. Thrid endopodal segment with apical setae slightly shorter than in second and third legs.

Fifth leg (Fig. 2 A), biramous, composed of wide baseoendopod (fused basis and endopod) and much smaller ovoid exopod, without connecting plate and not fused medially. Baseoendopod with outer basal seta long and smooth, arising from long setophore, ornamented with two large pores on anterior surface, one close to outer margin and other close to distal margin on endopodal lobe. Endopodal lobe relatively wide, trapezoidal, extending slightly beyond proximal third of exopod in length, armed with four stout, bipinnate setae, with length ratio (from inner side) 1: 1.1: 3.6: 1.9. Exopod about 1.6 times as long as maximum width, ornamented with slender spinules along inner margin, several spinules on posterior surface close to outer margin proximally, and large cuticular pore on anterior surface close to outer distal corner, armed with five setae; innermost seta strong and bipinnate, other four setae smooth and slender. Length ratio of five exopodal setae, from inner side, 1: 1.1: 0.6: 0.2: 0.3.

Sixth legs (Fig. 2 A) completely fused together, indistinct, forming simple operculum covering single gonopore, without any ornamentation, each with outer short pinnate seta and even much shorter smooth inner spine; setae directed outwards and somewhat anteriorly.

Male. Body length 442 μm. Habitus, ornamentation of almost all somites and caudal rami (Fig. 4 A), rostrum (Fig. 4 B), colour, antenna, labrum, paragnaths, mandibula, maxillula, maxilla, maxilliped, second swimming leg, third swimming leg, and fourth swimming leg similar to female. Prosome/urosome ratio 1.05, greatest width at posterior end of cephalothorax, body length/width ratio about 4.3; cephalothorax 1.4 times as wide as genital somite. Genital somite and first abdominal (third urosomite) not fused.

Genital somite (Fig. 4 A) 1.6 times as wide as long, with small and longitudinally positioned spermatophore visible inside on left side, which somewhat shorter than somite and nearly three times as long as wide.

Thrid urosomite (Fig. 4 A) with posterior continous row of large spinules ventrally (between ventral pair of sensilla; pair no. 70).

Anal somite (Fig. 4 A) with only one row of spinules near pore no. 86 (note: two rows in female).

Caudal rami (Fig. 4 A) slightly more elongated than in female, but with similar armature and ornamentation (although only three ventral spinules at base of inner apical seta).

Antennula (Fig. 4 B) broken off on both sides after second segment, thus complete armature unknown. First segment with several spinules on inner margin. Armature of first and second segment same as in female.

First swimming leg (Fig. 4 C) with smooth and distally inflated modified inner spine on basis, about as long as basis and directed distally; inner margin of basis smooth.

Third exopodal segment of left second swimming leg (Fig. 4 D) abnormal, with three inner setae inserted very close to each other about midlenght of segment; right second swimming leg as in female (normal).

Fifth legs (Fig. 4 A, E) smaller than in female and with baseoenopods fused medially, but with similar ornamentation. Endopodal lobe broad, convex, not extending to middle of exopod, unornamented (except for medial cuticular pore), with inflated inner distal margin, with only two elements: inner unipinnate spiniform element slightly shorter than baseoendopod and about twice as long as outer slender and sparsely bipinnate seta. Exopod with less ornamentation along inner margin, and much shorter than in female, only 1.1 times as long as wide, but with additional minute inner seta (arrowed in Fig. 4 E), without third seta from inner side (so number of elements same as in female, but setae not homologous if simply numbered from inner side); spiniform bipinnate seta much shorter than in female (arrowed in Fig. 4 E).

Sixth legs (Fig. 4 A) completely fused basally to each other and to somite, forming single flap with almost straight margin, each with three smooth setae, and ornamented with single pore on anoterior surface; length ratio of setae, from inner side, 1: 2.9: 1.3.

Variability. As only one male and one female were collected and examined, it cannot be established wich of the small differences in ornamentation (such as the ventral row of spinules between sensilla no. 70; compare Figs. 2 A and 4A) are a result of sexual dimorphism and which represent intraspecific variability. The third exopodal segment of the second swimming leg in male with three inner setae (Fig. 4 D) is most probably just an abnormality, as the same segment on the opposite leg shows no difference from that in the female.

Remarks. The swimming legs armature formula, relative length of the first endopodal segment of the first swimming leg, and short caudal rami of Ameira zahaae sp. nov. would suggest its close relationship with the cosmopolitan A. parvula (Claus, 1866) and the Californian A. parvuloides Lang, 1965. Ameira parvuloides was described by Lang (1965) with a great hesitation, given its close similarity with A. parvula and an amazing array of variability reported for the latter species, as observed for many species with a presumed cosomopolitan distribution. Ameira pavula was also recorded in Korea and partly redescribed by Chang (2007), which was also repeated in Chang (2009, 2010) (see the Introduction section above).

Lang (1948) gave an extensive overview of previous records of A. parvula, synonymising several forms, and listing this species for 16 countries from Europe, Africa, and North America. After that, the species was reported by almost everybody who surveyed marine harpacticoids in his/her area of study. Nicholls (1940) found it in Canada, Noodt (1952) in Germany, Noodt (1955) in Turkey, Noodt (1956) in Germany, Pesta (1959) in Italy, Wells (1961) in the Great Britain, Vervoort (1962) in New Caledonia, Petkovski (1964) in Portugal, Vilela (1965) in Portugal, Griga (1969) in Russia, Wells (1970) in the Great Britain, Apostolov (1972) in Bulgaria, Por & Marcus (1972) in Egypt, Marinov (1974) in Bulgaria, Mielke (1974) in Spitsbergen (Norway), Pallares (1975) in Argentina, Mielke (1975) in Germany, Chislenko (1917) in the Franz Joseph Land (Russia), Apostolov (1977) in Bulgaria, Caccherelli & Rossin (1979) in Italy, Arlt (1983) in the Baltic Sea, Wells & Rao (1987) in India, Apostolov & Pandourski (1999) in the Antarctic, and this chronological list is by no means exhaustive. Thus, it was not a big surprise when Chang (2007) reported it from Korea, although this was the first record for the Northwestern Pacific, and he did notice some morphological differences from the closest (Indian) population.

This was not, however, the first time that morphological differences were observed in this cosmopolitan species, and several taxonomists pointed some features of their populations that differed from the figures provided by Lang (1948), or some others. Mielke (1975) lists five differences between his German population and material he had examined a year earlier from Spitsbergen (Mielke 1974). The latter population was reported with three setae on the basis of mandibula, while the population from New Caledonia, as reported by Vervoort (1962), had only one seta on this segment, as well as a one-segmented antennal exopod. Wells & Rao (1987) reported two setae on the basis of mandibula in the Indian population. Pallares (1975) observed that in the Argentinian population the exopod of the male fifth leg is much longer than in any other population. Most researchers contributed the differences they observed to different styles of drawing, or to the presumed great variability of this widely distributed species, and nobody challeanged its status or tried to redescribe his/her population in great detail, although partial redescriptions were provided by several authors. After recent advances in the combined molecular and morphological approach on presumably widely distributed harpacticoid (Karanovic & Cooper 2011) and cyclopoid (Karanovic & Krajicek 2012) copepods, it became plausible to consider A. parvula as a speciescomplex. What is holding this complex together is the armature formula of the swimming legs, short caudal rami, and first endopodal segment of the first leg about as long as exopod. The first two are certainly plesiomorphic character states, as they are shared with a number of other Ameira species (the whole lacustris -group has the same armature formula), and the third feature may have easily arisen a number of times convergently, if not also being a plesiomorphic character sate (and most probably it is). That is why we studied two Korean populations presented here in great detail (one from the West Sea, the other from the South Sea), as they both could be identified within the wide concept of the very variable A. parvula. They not only proved to be different species, but also both differed markedly from the brackish population reported and illustrated by Chang (2007). We believe the latter represents an undescribed new Korean species, but we refrained here from naming it, as we did not examine any material and many features were not illustrated or described by Chang (2007, 2009, 2010) (mouth appendages, urosomal ornamentation, etc.).

Ameira zahaae differs from the specimens of “ A. parvula ” illustrated by Chang (2007) in a number of characters, the most prominent being the size and ornamentation of the caudal rami (much larger in A. zahaae and without dorsal proximal spinules; arrowed in Fig. 2 B), relative width of the anal operculum and anal sinus (both narrower in A. zahaae), segmentation of the antennal exopod (one-segmented in A. zahaae), relative size of the distal inner seta on the third exopodal segment of the fourth leg (shorter in A. zahaae; arrowed in Fig. 3 D), shape and size of the female fifth leg exopod, and relative size of the two innermost setae on the male fifth lex exopod (innermost minute, next one short and robust in A. zahaae; both arrowed in Fig. 4 E). Extremely reduced innermost seta on the male fifth leg exopod is an autapomorphic character state in A. zahaae, while similarly short and extremely robust spines on this appendage were only additionally observed in the Indian population of “A.

parvula ” by Wells & Rao (1987). The Indian population differs from our new species by many features, such as the presence of two setae on the mandibular basis (vs. one in A. zahaae), three seate on the baseoendopod of the male fifth leg (vs. two in A. zahaae), only three elements on the third endopodal segment of the second leg (vs. four in A. zahaae), ornamented inner margin of the caudal rami (vs. smooth in A. zahaae), wider anal sinus, relative length of the outermost seta on the baseoendopod of the fifth leg in female etc., and in our opinion also represents an undescribed new species. All other populations of A. parvula have been reported to have a much more slender and longer spine on the fifth leg exopod in male, and differ from A. zahaae by at least several other characters. Unfortunately, many characters and almost all microcharacters cannot be compared, and to revise this speciescomplex based on examination of material from around the world was beyond the scope of this paper.

Ameira zahaae differs from A. parvuloides by the shape and ornamentation of the caudal rami, armature of the mandibular basis, ornamentation of the maxilliped, relative length of the third endopodal segment of the first swimming leg, relative length of the distal inner seta on the third exopodal segment of the fourth leg, length and shape of the fifth leg exopod, and relative length of the elements on the fifth leg in male (see Lang 1965). Major differences between A. zahaae and A. kimchi sp. nov. are discussed in the Remarks section of the latter species (see below).