Afropinnotheres ratnakara, Ng, Peter K. L. & Kumar, Appukuttannair Biju, 2015

Ng, Peter K. L. & Kumar, Appukuttannair Biju, 2015, A new species of Afropinnotheres Manning, 1993 (Crustacea, Brachyura, Pinnotheridae) from southwestern India, the first record of the genus from the Indian Ocean, with a review of the Pinnotheridae of India and adjacent seas, Zootaxa 3947 (2), pp. 264-274 : 267-272

Afropinnotheres ratnakara n. sp.

( Figs. 1–4 )

Pinnotheres sp. —? Doflein 1904: 124, text fig. 11 [nec text fig. 10 as originally printed] ( South Africa);? Tirmizi & Ghani 1996: 89, fig. 34 ( Pakistan).

Material examined. Holotype: female (8.89×8.10 mm) (ZSI/ WGRC /IR/INV.4148), from brown mussel Perna perna (Linnaeus, 1758) (= P. i ndi ca Kuriakose & Nair, 1976) ( Mytilidae ), Kovalam, 8.3°N – 77.2°E, Thiruvananthapuram, Kerala, southwestern India, 5–10 m depth, coll. A. B. Kumar & R. Ravinesh, 31 May 2014. Paratypes: 2 males (5.69×5.23 mm, 5.24×5.12 mm), 2 flattened ovigerous females (10.91×8.19 mm, 8.72×6.81 mm), 1 female (8.61×7.27 mm), 1 deformed female (ca. 8.98×6.90 mm), 1 young female (6.71×5.97 mm) (DABFUK-AR-BR 20, 21/ ZRC), same data as holotype.

Diagnosis. Female: Carapace subcircular, slightly wider than long, width to length ratio 1.10–1.18; dorsal surface mostly smooth, glabrous, lateral regions with scattered short setae; front projecting anteriorly beyond orbits, entire, margin slightly convex to almost straight ( Figs. 1 A, B; 2A). Eyes small, barely visible in dorsal view; mobile, completely filling orbit ( Figs. 1 A, B; 2A, B). MXP3 outer surface with scattered short setae; propodus about 2 times as long as high, distinctly conical, subequal or shorter than carpus; dactylus subspatuliform, elongate, inserted just before base of propodus, tip reaching well beyond propodal apex; ischiomerus ca. twice as long as wide, with faint suture demarcating ischium, merus, outer margin convex, inner margin with proximal 2/3 gently concave, angular at widest point; exopod stout, ca. 3/4 length of ischiomerus, margins convex, flagellum 2– segmented ( Fig. 2 C). Chela short, dactylus ca. half palm length; palm slender, mesioventral margin distinctly setose; outer surfaces of palm, fingers (except for distal part) with numerous short setae; dactylus occlusal margin with large submedian tooth; pollex occlusal margin with 1 low proximal tooth, 1 submedian tooth ( Fig. 2 A, D). Ambulatory legs dorsally, ventrally unarmed; outer surface covered with scattered very short setae or glabrous, ventral margins with scattered long, short setae, without natatory setae; relative lengths of meri P2<P3<P4>P5; P2– P5 dactyli subequal; P2 dactylus a third propodal length, P3, P4 dactyli about half propodal length; P5 dactylus ca. 2/3 propodal length ( Fig. 4 A–D). Abdomen extending to buccal region, covering bases of ambulatory legs; telson distinctly recessed into distal margin of somite 6 ( Fig. 2 E). Male: Carapace circular, slightly wider than long, width to length ratio 1.02–1.07; dorsal surface covered with numerous short setae, appears pubescent; front distinctly projecting anteriorly, margin slightly sinuous, entire ( Figs. 1 C, 3A). Eyes distinctly visible in dorsal view ( Figs. 1 C, 3A). MXP3 as in female but ischiomerus proportionately shorter; dactylus slightly shorter; faint suture between ischium, merus may be absent ( Fig. 3 B). Anterior thoracic sternum with sternites 1, 2 fused, with shallow convex suture (towards buccal cavity); suture between sternites 2, 3 shallow, sinuous; sternites 3, 4 completely fused, very wide; sterno-abdominal cavity reaching to just before suture between sternites 2, 3 ( Fig. 3 C). Chela relatively stouter, shorter than in female ( Fig. 3 G). Ambulatory legs dorsally, ventrally unarmed; outer surface covered with numerous short setae, appearing almost pubescent, no other long setae, without natatory setae; relative lengths of meri P2 = P3<P4>P5; P2–P4 dactyli subequal, P5 dactylus slightly shorter than others; P2–P5 dactylus about half propodal length ( Fig. 4 E–H). Abdomen slender; widest at somites 2, 3, tapering distally to evenly rounded telson; telson subtriangular with convex lateral margins, longer than wide ( Fig. 3 D). G1 slender, long, tip gently curved; margins lined with long setae ( Fig. 3 E). G2 very short, with flattened tip ( Fig. 3 F).

Etymology. The name is derived from the old Sanskrit name for the Indian Ocean, Ratnakara . The name is used as a noun in apposition.

Remarks. Compared to A. crosnieri , the male chela of A. ratnakara n. sp. is relatively more elongated ( Fig. 3 G) (relatively shorter in A. crosnieri, Manning 1993 : fig. 4c); the female legs (notably the merus) are proportionately longer ( Fig. 4 A–D) (shorter in A. crosnieri, Manning 1993 : fig. 2d–g); there are no natatory setae on any of the male and female P2–P5 ( Fig. 4 ) (distinct in at least P2 and P 3 in A. crosnieri, Manning 1993 : figs. 2a, e, f, 3a); the surfaces of the male P2–P4 are covered with low pubescence ( Fig. 4 E–H) (relatively glabrous in A. crosnieri, Manning 1993 : fig. 4c–g); the telson of the male abdomen is more triangular in shape ( Fig. 3 D) (more semicircular in A. crosnieri, Manning 1993 : fig. 4h); and the female telson is more prominently recessed into somite 6 ( Fig. 2 F) (less distinctly so in A. crosnieri, Manning 1993 : fig. 3b).

Afropinnotheres guinotae is known only from one male specimen. The male of A. ratnakara n. sp. differs from it in having the carapace more rounded in shape ( Figs. 1 C, 3A) (proportionately wider in A. guinotae, Manning 1993 : fig. 5a); the outer surface of the MXP3 only has scattered setae ( Fig. 2 C) (conspicuously setose in A. guinotae, Manning 1993 : fig. 5b); the meri of the P2–P5 are proportionately longer ( Fig. 4 E–H) (relatively shorter in A. guinotae, Manning 1993 : fig. 6b–e); there are no natatory setae on any of the male P2–P5 ( Fig. 4 E–H) (at least on P2 and P 3 in A. guinotae, Manning 1993 : fig. 6b–e); and the telson of the male abdomen is more acutely triangular with a rounded tip ( Fig. 3 D) (broadly triangular with tip subtruncate in A. guinotae, Manning 1993 : fig. 5d).

Afropinnotheres ratnakara n. sp. can be distinguished from A. larissae by having the male carapace and pereiopods distinctly tomentose ( Figs. 1 C, 4E–H) (dorsal surfaces almost glabrous or weakly tomentose and pereiopods in A. larissae, Manning 1993 : figs. 7a, b, g–j, 8a, b, d–f); the male front is more entire, being barely sinuous ( Fig. 3 A) (sinuous and clearly emarginate in A. larissae, Manning 1993 : figs. 7a, 9a); the female front is slightly produced anteriorly, extending slightly beyond orbits ( Figs. 1 A, B, 2A) (not protruding beyond orbits in A. larissae, Manning 1993 : figs. 7a, 8a); the male and female chelae relatively more elongated ( Figs. 2 D, 3G) (relatively shorter in A. larissae, Manning 1993 : figs. 7f, 8d, e); the dactylus of P5 of the female is subequal in length to those in P2 and P3 ( Fig. 4 D) (longest in A. larissae, Manning 1993 : fig. 7j); and there are no natatory setae on the male P2–P5 ( Fig. 4 ) (with long setae in A. larissae, Manning 1993 : figs. 7a, b, 9a).

Afropinnotheres ratnakara n. sp. can be distinguished from A. monodi by the female front been slightly produced anteriorly, extending slightly beyond the orbits ( Figs. 1 A, B, 2A) (not protruding beyond orbits in A. monodi, Manning 1993 : fig. 10a); the ambulatory meri are proportionately longer ( Fig. 4 ) (shorter in A. monodi, Manning 1993 : figs. 10d–g, 11d–h), and there are no natatory setae on the legs (with distinct setae at least on P2 and P 3 in A. monodi, Manning 1993 fig. 11f, g).

Doflein (1904: 124, pl. 37 figs. 3, 4) reported an unidentified species of Pinnotheres from Algoa Bay, east of the Cape of Good Hope, South Africa (host unknown). The figure of the female specimen ( Doflein 1904: pl. 37 figs. 3, 4) agrees well with A. ratnakara n. sp. in carapace shape and general features, including the proportions of the legs and abdomen. The MXP3 of his Pinnotheres sp. ( Doflein 1904: text fig. 10), however, differs markedly from that of A. ratanakara , with the ischiomerus proportionately much longer and slender, the dactylus distinctly spatuliform and the exopod only about a third or half the length of the ischiomerus. The MXP3 of A. ratanakara actually agrees much better with that Doflein figured for his new species, Pinnotheres villosissimus , obtained from a holothurian near Padang, Sumatra. This species is currently placed in Holotheres ( Ng & Manning 2003) . The first author had a chance to examine the holotype female of Pinnotheres villosissimus in the Berlin Museum and its MXP3 structure is actually not the one figured by Doflein (1904: text fig. 11) as belonging to this species. It instead matches Doflein’s text figure 10, the one he cites as belonging to Pinnotheres sp. The first author has also examined many specimens of P. villosissimus from Papua New Guinea (see Van Den Spiegel & Jangoux 1989), and all their MXP3 are similar in form. It therefore appears that Doflein (1904) inadvertently transposed the figures of his Pinnotheres villosissimus and Pinnotheres sp., substituting one for the other. In such a case, the figure he provided for Pinnotheres villosissimus ( Doflein 1904: text fig. 11) is actually that for his Pinnotheres sp. In fact, the descriptions of the MXP3 of these two species by Doflein actually agree better with the figures as elucidated here than what was printed originally. As such, Doflein’s (1904) Pinnotheres sp. may well be referable to what is described here as Afropinnotheres ratnakara n. sp.

Doflein’s (1904) mislabeling of the MXP3 structures has taxonomic consequences. Nobili (1905, 1906) in describing a new species, Pinnotheres pilumnoides from the Red Sea (on the basis of one female with no host data), noted that his species was close to P. villosissimus except that its MXP3 was very different to that figured by Doflein for this species. The MXP3 of P. pilumnoides (cf. Nobili 1906: fig. 12) superficially resembles that of P. villosissimus except that the ischiomerus appears to be stouter and the dactylus is shorter than the propodus. The first author has noticed that the proportions of the MXP3 dactylus of P. villosissimus vary considerably in his Papua New Guinea material (unpublished data) so Nobili’s (1905) of P. pilumnoides may be a junior synonym of P. villosissimus . Another species, Pinnotheres dofleini Lenz , in Lenz & Strunck, 1914, was described on the basis of one male specimen from Simon Bay (from an ascidian) in South Africa; with Lenz believing that this was the male of the Pinnotheres sp. described by Doflein (1904) from a female. He noted that the MXP3 of his male specimen was the same ( Lenz & Strunck 1914: 282) as that figured by Doflein (1904: text fig. 10). In view of the present observation that Doflein confused his figures; Lenz in Lenz & Strunck’s (1914) specimen may well be the same as P. villosissimus s. str., although their hosts are different. In any case, the type specimens of P. pilumnoides Nobili, 1905 , and Pinnotheres dofleini Lenz in Lenz & Strunck, 1914, need to be re-examined before any firm taxonomic decisions take place.

Chopra (1931: 312, text figs. 3, 4, pl. 7 fig. 2) reported many specimens of H. villosissimus from the Andamans and noted that they agreed well with the description and figures of Doflein (1904), and figured the general habitus, chela, and male abdomen. They also agree with the material examined herein. Chopra nevertheless commented that the MXP3 of his specimens agree with that described by Doflein, although he did not figure it. His description of the carpus, propodus, and dactylus could be for either of Doflein’s taxa. Chopra did not indicate if he also denuded the ischiomerus to determine the shape and proportions. These specimens will need to be reexamined to be certain of their identity.

Tirmizi & Ghani (1996: 89, fig. 34) described and figured an unidentified Pinnotheres species from a bivalve in Pakistan, which agrees in many respects with Afropinnotheres ratnakara n. sp. They may be conspecific.

With regard to other pinnotherids, Afropinnotheres ratnakara n. sp. superficially resembles Nepinnotheres margaritiferae ( Laurie, 1906) , which has been reported as found in Mytilus sp. (= Indian Perna ) ( Mytilidae ) and Pinctada imbricata Röding, 1798 [as Margaritifera vulgaris (Schumacher, 1817) ] ( Pteriidae ) in Sri Lanka ( Southwell 1911). The anterior part of the female carapace in N. margaritiferae is nevertheless more quadrate with the anterolateral margins more angular (more rounded in A. ratnakara n. sp., Figs. 1 A, B; 2A), the MXP3 propodus is more elongated, with the dactylus short and inserted medially (propodus short and conical with long dactylus inserted sub-basally in A. ratnakara n. sp., Figs. 2 C, 3B), and the ambulatory meri and dactyli are proportionately longer (relatively shorter in A. ratnakara n. sp., Figs. 1 , 4 ) (cf. Laurie 1906: text figs. 10, 10a; Southwell 1911: pl. 3 figs. 3, 3a).

Afropinnotheres ratnakara n. sp. resembles Pinnotheres mactricola in the carapace shape, but the merus of the P5 of P. mactricola is proportionately shorter ( Alcock & McArdle 1903: pl. 62 figs. 4, 5) (longer in A. ratnakara n. sp., Figs. 1 , 2 A, 4) and the propodus of MXP3 is proportionately longer and the dactylus only reaches to the tip of the propodus ( Alcock & McArdle 1903: pl. 62 fig. 5b) (propodus short and conical with the dactylus extending beyond the tip of the dactylus in A. ratnakara n. sp., Figs. 2 C, 3B).

Figures

FIGURE 1. Afropinnotheres ratnakara n. sp., overall habitus. A, holotype female (8.89 × 8.10 mm) (ZSI / WGRC / IR / INV. 4148); B, paratype female (6.71 × 5.97 mm) (DABFUK / ZRC); C, paratype male (5.69 × 5.23 mm) (DABFUK / ZRC).

FIGURE 2. Afropinnotheres ratnakara n. sp. A, C – E, holotype female (8.89 × 8.10 mm) (ZSI / WGRC / IR / INV. 4148); B, paratype female (8.61 × 7.27 mm) (DABFUK / ZRC). A, overall habitus; B, epistome, antennae, antennules and orbit; C, left MXP 3; D, outer view of left chela; E, female abdominal somites 5, 6 and telson. Scales = 1.0 mm.

FIGURE 3. Afropinnotheres ratnakara n. sp., paratype male (5.69 × 5.23 mm) (DABFUK / ZRC). A, dorsal view of carapace; B, left MXP 3 (setae not drawn); C, anterior thoracic sternum and sternoabdominal cavity; D, male abdomen; E, right G 1; F, right G 2; G, outer view of left chela. Scales: A – D = 1.0 mm; E, F = 0.5 mm.

FIGURE 4. Afropinnotheres ratnakara n. sp., right ambulatory legs. A – D, holotype female (8.89 × 8.10 mm) (ZSI / WGRC / IR / INV. 4148); E – H, paratype male (5.69 × 5.23 mm) (DABFUK / ZRC). A, E, P 2; B, F, P 3; C, G, P 4; D, H, P 5. Scales = 1.0 mm.