Alpheus mangalis Anker 2023, sp. nov.

Alpheus mangalis sp. nov.

(Figs. 36–40, 52B)

(?) Alpheus sp. cf. audouini .— Johnson 1962: 53 (part.).

(?) Alpheus microrhynchus. — Johnson 1965: 9 (part.) [not A. microrhynchus De Man, 1897].

(?) Alpheus euphrosyne. — Banner & Banner 1966: 130 (part.?) [not A. euphrosyne De Man, 1897].

(?) Alpheus euphrosyne euphrosyne. — Banner & Banner 1982: 232 (part.?, not fig. 73); Chace 1988: 27 (part.?) [not A. euphrosyne De Man, 1897].

Type material. Holotype, male (cl 11.4 mm, tl 33.5 mm, chl 17.5 mm), ZRC 2014.0667, Singapore, Pulau Ubin, Kampung Melayu, mudflat near mangrove, leg. B.Y. Lee & B.W. Lee, 26.09.2011. Paratypes: 1 ov. female (cl 12.0 mm), ZRC 2014.0683, same collection data as for holotype; 2 males (cl 7.5, 7.7 mm), 2 females (cl 7.0, 8.3 mm), 1 ov. female (cl 7.1 mm), 1 juv. male (cl indet.), ZRC 2014.0685, Singapore, Pulau Ubin, OBS Camp 2, mouth of Sungei Teris, sta. SW77, mud, gill net, leg. H.H. Ng & M. R. bin Duria, 24.10.2012; 5 males (cl 7.3–9.4 mm), 3 ov. females (cl 8.2–11.0 mm), OUMNH. ZC. 2019.06.60, Singapore, Pulau Ubin, Chek Jawa, mangrove, yabby pump, leg. K.L. Yeo, 21.08.2001; 1 male (cl 10.4 mm), 1 ov. female (cl 10.5 mm), ZRC 2014.0666, same collection data as for previous paratypes; 5 males (cl 7.6–11.3 mm), 1 female (cl 9.2 mm), 4 ov. females (cl 9.4–11.5 mm), MNHN-IU-2018-5732, Singapore, Pulau Ubin, between OBS camps 1 and 2, sta. M04, mudflat, edge of mangrove, leg. J.C. Mendoza, Y.L. Lee & R. Tan, 06.03.2012; 1 male (cl 10.5 mm), 1 ov. female (cl 12.8 mm), ZRC 2014.0684, same collection data as for previous specimens [M04-141]; 2 males (cl 8.0, 8.1 mm), MNHN-IU-2018-5750, Singapore, Pulau Ubin, west of Celestial Resort, sta. M01, mangrove, mounds of Thalassina sp., mud combing, leg. D.L. Rahayu & K.S. Tan, 06.03.2012; 1 male (cl 7.7 mm), 1 female (cl 7.1 mm), OUMNH. ZC. 2019.06.61, Singapore, mouth of Sungei Besar, sta. SW95, sandy shore with mudflat and mangrove, leg. K.S. Koh et al., 26.10.2012; 1 male (cl 9.3 mm), MNHN-IU-2018-5743, same collection data as for previous specimens [JS-2430]; 1 male (cl 10.2 mm), MNHN-IU-2018-5592, same collection data as for previous specimens [JS-2429];> 40 specimens of both sexes (cl indet.), ZRC 2014.0678, Singapore, Sungei Buloh, sta. KR3, mangrove, leg. Y.L. Teo & N. Sivasothi, 12.03.2004 [2011-SIN-082]; 2 males (cl 8.9, 9.3 mm), 2 ov. females (cl 9.8, 10.0 mm), MNHN-IU-2018-5600, same collection data as for previous specimens; 1 male (cl 9.8 mm), MNHN-IU-2018-5749, Singapore, Lim Chu Kang, mangrove, sta. SW106, mud, hand and tangle nets, leg. A. Anker, B.Y. Lee & D. Uyeno, 28.10.2012 [JS-2414].

Additional material. Singapore: 1 male (cl 6.0 mm), 2 females (cl 5.5, 6.5 mm), ZRC 2014.0679, Pulau Ubin, 01°24.340’N 103°58.253’, leg. K.S. Tan et al., 12.02.2011 [4017-4019]; 2 males (cl 6.6, 9.3 mm), ZRC 2014.0721, Sungei Simpang, sta. MF49, leg. H.H. Ng, 17.02.2012 [49011-49012]; 1 ov. female (cl indet.), OUMNH. ZC. 2019.06.62, Sungei Buloh, Left Main Stream, sta. KR4, mangrove, leg. Y.L. Teo, 05.03.2004 [2011-SIN-031]; 1 female (cl 10.3 mm, without rostrum), MNHN-IU-2018-5747, same collection data as for pervious specimen [2011-SIN-025]; 1 female (cl 11.2 mm), OUMNH. ZC. 2019.06.62, Sungei Buloh, sta. KR3, mangrove, leg. Y.L. Teo, 13.02.2004 [2011-SIN-036]; 1 ov. female (cl 9.5 mm, without rostrum), OUMNH. ZC. 2019.06.63, Sungei Buloh, sta. KR3, mangrove, leg. Y.L. Teo, 12.03.2004 [2011-SIN-047]; 2 males (cl 7.3, 7.7 mm), OUMNH. ZC. 2019.06.64, Sungei Buloh, mangrove, leg. Y. Cai, 19.04.1997 [2011-SIN-061];> 20 specimens of both sexes (cl indet.), MNHN-IU-2018-5753, Sungei Buloh, East Channel, mangrove, leg. Y.L. Teo, 13.02.2004 [2011-SIN-078];> 10 specimens of both sexes (cl indet.), FLMNH UF 68863, Sungei Buloh, East Channel, mangrove, leg. Y.L. Teo & K.M. Sheng, 21.02.2004; 2 males (cl 6.5, 8.9 mm), 1 female (cl 8.7 mm), 1 ov. female (cl 7.9 mm), ZRC 1996.44, Sungei Buloh, mangrove, leg. P.K.L. Ng et al., 05.08.1995; 1 male (cl 8.0 mm), 1 ov. female (cl 8.4 mm), ZRC 2014.0720, Sungei Buloh, mangrove, leg. C. Schubart, 14.01.2002; 2 males (cl 7.4, 8.0 mm), 1 female (cl 7.4 mm), 4 ov. females (cl 8.7–9.2 mm), ZRC 2004.0500, Sarimbun-Poyan mangrove, leg. H.H. Tan et al., 13– 20.01.2004; 1 female (cl 8.0 mm), 3 ov. females (cl 8.7–9.0 mm), ZRC 2014.0688, Sarimbun Beach, near Jalan Bahtera Scouts Camp, mudflat, H.H. Ng, Y.L. Teo & H. Wong, 14.02.2012 [48198-48201]; 2 males (cl 7.3, 7.4 mm), ZRC 1996.43, Lim Chu Kang, mangrove, leg. P.K.L. Ng, 18.08.1995; 1 ov. female (cl 9.2 mm), ZRC 2014.0691, Singapore, Lim Chu Kang, mangrove, sta. Y595, 04.04.1989; 1 male (cl 7.5 mm), ZRC 1989.3661, Lim Chu Kang, mangrove, in mound of Thalassina sp., leg. P.K.L. Ng, 17.03.1987; 1 male (cl 6.8 mm), 1 ov. female (cl 7.9 mm), ZRC 2014.0689, Lim Chu Kang—Sarimbun Scouts Camp, mangrove, leg. H. Wong et al., 21.07.2011 [27136–27137]; 1 male (cl 6.7 mm), 1 female (cl 5.5 mm), ZRC 2014.0692, same collection data as for previous specimens [27138–27139]; 1 female (cl 8.0 mm), ZRC 2014.0687, Lim Chu Kang, sta. SW110, mangrove and adjacent mud flat, B.Y. Lee et al., 28.X.2012 [JS-2395]; 1 male (cl 6.3 mm), ZRC 2014.0693, Lim Chu Kang, sta. SW106, mangrove and adjacent mudflat, leg. A. Anker et al., 27.10.2012; 3 males, 2 females, 1 ov. female (cl. indet.), MNHN-IU-2013-14787, Lim Chu Kang mangrove, leg. A. Anker et al., 01.2002; 3 males (cl 6.1–7.3 mm), ZRC 2014.0690, Loyang, East coast of river mouth, mud, leg. TMSI team, 11.07.2012 [67156–67158]; 1 male (cl 11.3 mm), 1 ov. female (cl 12.6 mm), ZRC 1996.45, Mandai, mangrove, leg. P.K.L. Ng, 21.06.1990; 1 male (cl 9.2 mm), 1 ov. female (cl 8.5 mm), MNHN-IU-2013-14785, Pandan mangrove, low tide, in pairs under logs in mud, leg. A. Anker, 13.02.2002; 1 male (cl 8.3 mm), 1 female (cl 7.9 mm), ZRC 1979.4.3.1–2, Jurong, prawn ponds, sta. B17, leg. S. R.F. R.S., 01.06.1954 [J8098-8098]; 2 males (cl 7.8, 10.2 mm), 2 ov. females (cl 9.5, 10.4 mm), ZRC 1979.4.3.3-6, Jurong, prawn ponds, sta. B29, leg. S. R.F. R.S., 05.07.1954 [J8086-8089].

Malaysia: 1 ov. female (cl 11.3 mm), ZRC 1979.4. 3.8, Selangor, Port Klang (Port Swettenham), mudflats, leg. S. Kumar, 27.08.1968; 2 ov. females (cl 11.2, 12.0 mm), MNHN-IU-2018-5745, Johor, Muar, sta. 2, mudflats, leg. N.K. Ng. & J.C.Y. Lai, 10.02.2009; 1 male (cl 7.7 mm), MNHN-IU-2013-14786, Tanjong Sendili, leg. Y. Cai & N.K. Ng, 20.09.1998; 1 male (cl 6.2 mm), ZRC 1999.0571, Sarawak, Bako, Telok Delima, leg. K.L. Yeo, 29.06.1994; 1 male (cl 9.1 mm), 1 ov. female (cl 8.3 mm), ZRC 2014.0669, Sarawak, Kuching prawn farm, no further data.

Indonesia: 2 males (cl 10.2, 12.6 mm), 2 ov. females (cl 9.3, 14.4 mm, latter tl ~43.0 mm), MNHN-IU-2018- 5733, Java, Jepara, leg. D.L. Rahayu, 04.2010; 1 male (cl 9.2 mm), OUMNH. ZC. 2019.06.65, Lombok, Lembar, prawn ponds, fine mud, burrows in banks of brackish creek, low tide, leg. A. Anker & D.L. Rahayu, 14.05.2014; 1 male (cl 12.3 mm), 1 female (cl 13.0 mm), QM W25803-2, Papua, Ajkwa River estuary, 4°50’S 136°50’E, Environmental Laboratory, PT Freeport, Sta. Ajk-36, estuarine habitat, 30.03.2000; 5 males (cl 8.0– 13.6 mm), 1 ov. female (cl 9.7 mm), MNHN-IU-2018-5740, Papua, Ajkwa Island, mangrove, leg. A. Darmawan et al., 20.07.2012; 1 male (cl 7.4 mm, missing minor cheliped), ZRC 2014.0722, same collection data as for previous specimens; 3 males (cl 8.8–9.5 mm), 1 female (cl 11.4 mm), MNHN-IU-2018-5736, Papua, Kamora, mangrove, leg. A. Darmawan et al., 07.08.2012.

Philippines: 1 juv. female (cl 5.7 mm, both chelipeds detached, other pereiopods missing, identification somewhat tentative), ZRC 2014.0681, Palawan, Sabang, Underground River National Park, brackish river near cave entrance, leg. H. Freitag, 16.02.2001.

Taiwan: 1 male (cl 8.2 mm, missing minor cheliped), ZRC 2000.2132, Shinzhu, mangrove, leg. Y. Cai & C.W. Lin, 28.11.1997.

Australia: 2 males (cl 10.5, 12.1 mm), 1 ov. female (cl 11.7 mm), NTM Cr. 008307, Northern Territory, Darwin, Ludmilla Creek mouth, 1224.8’S 13051.7 E, undisturbed mangrove, low tide, leg. M. Burke, 04.06.1991; 1 male (cl 11.2 mm), NTM Cr. 008317, Northern Territory, Darwin, Ludmilla Creek mouth, 12°24.8’S 130°51.7’ E, disturbed mangrove, low tide, leg. M. Burke, 05.06.1991; 4 males (cl 13.0– 13.4 mm), 1 female (cl 14.0 mm), 1 ov. female (cl 14.4 mm), NTM Cr. 008305, Northern Territory, Darwin, mouth of Blackmore River, Channel Island, 12°37.3’S 130°56.6’ E, undisturbed mangrove, low tide, leg. M. Burke, 13.06.1991; 1 ov. female, NTM Cr. 013093, Northern Territory, Darwin, mouth of Blackmore River, Channel Island, 12°37.3’S 130°56.6’ E, undisturbed mangrove, low tide, leg. M. Burke, 12.06.1991; 1 male (cl indet., missing both chelipeds), NTM Cr. 013094, Northern Territory, Darwin, mouth of Blackmore River, Channel Island, 12°37.3’S 130°56.6’ E, undisturbed mangrove, low tide, leg. M. Burke, 17.06.1991; 1 male, 1 female (cl indet.), NTM Cr. 008305, Northern Territory, Darwin, Channel Island, near bridge, 12°34.9’S 130°55.4’ E, undisturbed mangrove, low tide, leg. M. Burke, 02.07.1991.

Tentative identification. Alpheus cf. mangalis sp. nov. New Caledonia: 2 males (cl 10.2, 11.6 mm), 1 ov. female (cl 11.6 mm), MNHN-IU-2019-3217, Dumbéa River estuary, mangrove, leg. C. Vadon, 22.09.1978.

Description. See Figs. 36–38. Medium-sized species of Alpheus (maximal cl 14.4 mm, tl ~43.0 mm). Carapace glabrous, without pubescence, with slight grooves. Rostrum short, triangular, distally acute, reaching or slightly overreaching mid-length of first article of antennular peduncle, occasionally minute or (rarely) absent; rostral carina present as low elevation, fading at eye level; rostro-orbital furrows poorly demarcated. Pterygostomial angle broadly rounded; cardiac notch deep.

Pleon smooth, without pubescence. Telson moderately broad, ovate-rectangular, gently tapering towards posterior margin, about 1.5 times as long as maximal width near proximal margin; lateral margins slightly convex; dorsal surface without trace of median depression, with two pairs of short spiniform setae inserted in deep pits at some distance from lateral margins, first pair at or just before telson mid-length, second pair at about 0.7 of telson length; posterior margin broadly rounded, with two pairs of slender spiniform setae at posterolateral angles, lateral much shorter than mesial.

Antennular peduncle with stylocerite broad, markedly convex laterally, with acute tip, latter reaching, but not overreaching distal margin of first article; ventromesial carina with broad blunt tooth; second article about 2.3 times as long as wide. Antennal peduncle with basicerite armed with strong sharp tooth; carpocerite reaching slightly beyond scaphocerite; scaphocerite with lateral margin nearly straight; blade broad, separated from broad distolateral tooth by deep cleft; anterior margin of blade broadly rounded, exceeded by sharp distolateral tooth.

Third maxilliped with antepenultimate article not particularly broadened; penultimate article moderately long, widening distally, about three times as long as maximal width; ultimate article with dense transverse rows of short serrulate setae on mesial surface and some longer setae near apex; coxal lateral plate bluntly protruding dorsally; exopod distinctly overreaching end of antepenultimate article.

Major cheliped of A. edwardsii - type. Merus stout, about twice as long as wide; ventromesial margin distally armed with strong sharp tooth. Carpus very short, cup-shaped. Chela large, heavy, with fingers about 0.6 length of palm; all surfaces smooth, without granulation. Mesial face with weak mesial transverse ridge extending obliquely from proximal edge of mesial longitudinal groove to ventral surface of palm, although far from reaching it. Lateral face of palm with lateral longitudinal groove deep, subrectangular; proximal half without distinct transverse ridge. Dorsal shoulder gently sloping into broad transverse groove with angle of about 45°. Ventral shoulder pronounced, slightly protruding in lateral view, broadly rounded. Pollex with mesial face lacking subdistal mesial ridge and adjacent proximal protuberance; distomesial angle distinctly superior to 90°, blunt; lateral face with distolateral angle wide, poorly marked. Dactylus without dorsal ridge; dactylar plunger stout, elongate, with anterior margin clearly demarcated from ventral margin of dactylus; distal surface of plunger rounded anteriorly, otherwise flattened. Adhesive discs small.

Male minor cheliped with chela strongly balaeniceps. Merus distinctly slenderer than that of major cheliped, almost three times as long as wide; ventral margin with distomesial angle armed with stout, sharp tooth, as in major cheliped. Chela feebly swollen, slender in lateral view, with fingers about 0.8 length of palm; all surfaces smooth, without granulation. Palm subcylindrical, compressed, feebly swollen; mesial and lateral longitudinal grooves poorly marked; dorsal shoulder poorly developed, present only as low elevation gently sloping into broad dorsal transverse groove; ventral transverse groove and adjacent shoulder similarly poorly developed, recognisable as shallow sinus and low bump, respectively. Pollex with mesial surface bearing row of balaeniceps setae on low crest extending from base to about mid-length of pollex; lateral surface with similar row of balaeniceps setae as on mesial surface. Dactylus with marked lateral expansion (balaeniceps expansion) in proximal half, about twice as long as maximal width; lateral and mesial dactylar ridges each with dense rows of balaeniceps setae. Cutting edges of both fingers shallowly excavated on each side of sharp, blade-like ridge.

Female minor cheliped simple, not balaeniceps. Chela slender, not particularly swollen, with fingers subequal to palm; all surfaces smooth, not granulated. Palm with mesial longitudinal groove not distinct; lateral longitudinal groove distinct, but very shallow; dorsal and ventral transverse grooves and shoulders absent. Fingers simple, with sharp cutting edges, not gaping when closed; fingertips moderately curved and crossing.

Second pereiopod with ratio of carpal subarticles approximately equal to 4: 2.1: 1: 1: 1.5. Third pereiopod relatively slender; ischium armed with stout spiniform seta on ventrolateral surface; merus about 5.2 times as long as maximal width, unarmed; propodus with five or six short spiniform setae on ventral margin and one pair of spiniform setae on distoventral margin adjacent to dactylus; dactylus almost half-length of propodus, spatulate, moderately expanded, slightly wider than propodus in dorsal view, with row of setae along mesial margin. Fourth pereiopod generally similar to third pereiopod, shorter and slenderer. Fifth pereiopod much slenderer than third and fourth pereiopods; ischium unarmed; propodus with single spiniform seta at mid-length, one distal spiniform seta adjacent to dactylus, and well-developed setal brush; dactylus subspatulate, about 0.4 length of propodus.

Male second pleopod with appendix masculina 0.8 length of appendix interna. Uropod with each protopodal lobe ending in subacute tooth distally; exopod and endopod broad, ovate; diaeresis of exopod complete, almost straight, with broadly subtriangular lobe near small distolateral spiniform seta and adjacent distolateral tooth; lateral margin of exopod broadly convex.

Eggs numerous (> 100 in larger females), small; egg diameter about 0.51 0.55 mm to 0.55 0.60 mm.

Colour pattern. Body (carapace and pleon) uniform dark olive-green, brown-green or green-blue; smaller individuals with broad transverse bands on pleon, one per pleonite; antennules and antennae greenish blue; flagella dull greenish; mesial face of major chela dark olive-green to blue-green; lateral face of major chela whitish or bluish; distal portion of both fingers pink; dactylar plunger greenish or pale green-yellow; minor chela dark bluish green; second to fifth pereiopods reddish; pleopods dull greenish or bluish; telson and uropods dark blue-green, uropodal exopod with deep blue area posterior to transverse suture (Figs. 39, 40).

Type locality. Pulau Ubin, Singapore (collection locality of the holotype).

Distribution. Tropical Indo-West Pacific from Taiwan to northern Australia (Fig. 52B); specific localities include: Taiwan (Shinzhu), Philippies (Palawan), Singapore (Pulau Ubin, Lim Chu Kang, Sungei Buloh, Jurong, etc.), Indonesia (Lombok, Papua), Malaysia (Selangor, Johor, Sarawak), and Australia (Northern Territory); possibly extending to New Caledonia (Dumbéa), but see below (closely related species?).

Etymology. The new species’s name refers to its typical habitat, mudflats within or near mangrove forests; used as an adjective.

Common name proposed. Lesser mangrove snapping shrimp.

Ecology and biology. Alpheus mangalis sp. nov. is one of the most common snapping shrimps on mangrove mudflats of Singapore, Malaysia and Indonesia. For instance, in Sungei Buloh and Pulau Ubin, Singapore, A. mangalis sp. nov. may be easily collected under large rocks embedded in mud, among mangrove roots, under wood logs, debris, etc. Like many other species of Alpheus associated with mangroves, this species appears to be euryhaline, living in marine water, but also tolerating brackish conditions. The large number of eggs and their small size suggest an extended larval development in A. mangalis sp. nov.

Taxonomic remarks. Alpheus mangalis sp. nov. can be easily separated from A. euphrosyne, A. eurydactylus, A. richardsoni, A. microrhynchus, A. cyanoteles, A. nomurai sp. nov. and A. takla sp. nov. by the presence of a stout, sharp tooth on the distomesial margin of the cheliped meri (Figs. 36E, G, 38B, G; this tooth is absent in all the afore-mentioned species, cf. Figs. 2E, 7C, G, 15B, G, 27B, etc.), and the longer and/or differently shaped dactylar plunger of the major chela (Figs. 38D, 40A, E; cf. Figs. 7D, 15D, 24D, 27D, 31C; Banner & Banner 1982: fig. 74e). In addition, A. mangalis sp. nov. differs from A. euphrosyne and A. eurydactylus by the smooth, non-granulated major chela surface (granulated in the other two species); from A. euphrosyne, A. eurydactylus, A. microrhynchus, A. cyanoteles, A. nomurai sp. nov. and A. takla sp. nov. by the absence of a subdistal mesial ridge on the major chela pollex and the absence of dorsal and ventral shoulder on the minor chela (present in all the other species, although less pronounced in A. nomurai sp. nov.); from A. euphrosyne by the non-overhanging dorsal shoulder of the major chela (overhanging in A. euphrosyne); from A. richardsoni by the absence of ventral sinus on the male minor chela (present in A. richardsoni); from A. microrhynchus and A. cyanoteles by the spatulate dactyli of the third to fifth pereiopods (which are subconical-trigonal in the other two species); and from A. euphrosyne, A. richardsoni, A. microrhynchus, A. cyanoteles, A. nomurai sp. nov. and A. takla sp. nov. by one or several features of the colour pattern (Fig. 39, 40; cf. Figs. 8, 18, 22, 24, 28, 32, 33).

The taxonomic identity of the New Caledonian material assigned to A. cf. mangalis sp. nov. remains to be confirmed. In most features, the New Caledonian specimens agree well with A. mangalis sp. nov.; however, the major chela pollex presents a very slight granulation not observed in the specimens from South-East Asia Therefore, and because of several other discrepancies, these specimens may represent a different species, perhaps more closely allied to A. lobidens De Haan, 1849. Some doubts also remain about the identification of the material of A. mangalis sp. nov. from the Philippines (juvenile specimen) and Taiwan (incomplete specimen). Finally, there is some recent evidence of the possible presence of either A. mangalis sp. nov. or a closely related taxon in India and Iran (A. Anker, pers. obs., based on photographs provided by M. Harikrishnan and H. Ashrafi, respectively). Therefore, additional sampling of Alpheus spp. in mangrove areas of these countries, combined with DNA sequencing, are needed to confirm the presence of A. mangalis sp. nov. in the South-China Sea, northern Indian Ocean and New Caledonia.