Sunipea callistus Santana, 2015, n. sp.
Creators: name: Santana, William
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Inachidae
Sunipea
Sunipea callistus

description: Sunipea callistus n. sp.
(Figures 1A, C; 2A, C; 3A, C; 4A, C, E; 5A, B)
Sunipea indicus —Griffin 1974: 7 [pro parte]; Griffin & Tranter 1986: 59 [pro parte].
Type material. Somali Republic, Cape Guardafui, Anton Bruun, stn 463, 11 °24’N- 51°35’E, 17.xii.1964, 75– 150 m, male holotype, cl 14.6 mm, cw 10.5 mm (USNM 1191775). Somali Republic, Cape Guardafui, Anton Bruun, stn 463, 11 °24’N- 51°35’E, 17.xii.1964, 75– 150 m, male paratype, cl 13.7 mm, cw 9.4 mm (USNM 1191774). Cape Guardafui, Anton Bruun, stn 453, 11 °11’N- 51°14’E, 17.xii.1964, 47– 49 m, ovigerous female paratype, cl 7.4 mm, cw 4.6 mm (USNM 135110).
Diagnosis. Carapace uniformly, densely covered with subequal tubercles. Rostrum bifurcated, straight. Ocular peduncle with sharp tubercles distally. Third, fourth antennal articles reaching the tip of rostrum; epistome without tubercles. Merus of the third maxillipeds with distinct crenulated margin medially ending in a spine. Sparse small tubercles irregularly distributed in thoracic sternite III; male thoracic sternites IV–VII with tubercles irregularly distributed. Male sterno-abdominal cavity longer than telson, leaving a gap between telson, anterior crenulated margin. Female abdominal somites 1–3 with tubercles; female telson without tubercles. Male gonopod 1 straight, slightly converging, with mesial lobe acute, upturned, forming a distinct groove, lateral margin with distinct velvet in distal third.
Description. Carapace piriform, 1.5 times longer than wide in males, females slender; surface densely covered with subequal tubercles uniformly distributed; hooked setae sparsely, with dense clusters between orbits, rostrum, hepatic, gastric, branchial regions; hepatic region with one long spine directed anterolaterally; metagastric, cardiac, mesobranchial, intestinal regions with 1 long, sometimes capitate, spine each; branchial region with 1 anteroventrolateral spine. Gastric region delimited by groove without tubercles, more evident in males; hepatic, branchial, cardiac, intestinal regions well defined. Rostrum bifurcated, straight, short, anteriorly directed; rostrum, orbital dorsal margins with tubercles. Supraorbital spines long, directed anteriorly; postorbital spines very short. Ocular peduncle constricted medially, armed with sharp tubercles distally. Antennular fossae longitudinally ovate, with smooth margins. Interantennular septum elongated, compressed laterally, forming distinct ventrally directed lobe. Antennal flagella short; third, fourth antennal articles long, slender, reaching the tip of rostrum. First, second antennal articles fused to epistome; second article with long spine in anterolateral angle, slightly directed anteriorly, with sub-equal tubercles near lateral margin. Epistome without tubercles, distinctly longer than wide. Epistomial spine, interantennular septum separated by small gap. Mouthfield subquadrate, protruded anteriorly, with crenulated anterolateral angles. Pterygostomian region subtriangular, with row of strong tubercles forming carinae, smaller tubercles present; separated from subhepatic region by shallow groove. Subhepatic region with long spine, crenulated tip in some specimens; small tubercles evenly distributed.
Third maxillipeds completely covering buccal frame. Exopod long, nearly reaching distal margin of merus; dorsal face with row of small tubercles parallel to lateral margin, otherwise irregularly distributed; mesial margin with strong spine in distal half. Ischium longer than broad; mesial margin almost straight; crista dentata with row of short setae, small acute teeth; dorsal face of ischium concave longitudinally, with distinct, well-spaced tubercles. Merus longer than half of ischium, with smaller tubercles; anterolateral margin strongly expanded, with distinct crenulated margin medially ending in a spine, few long setae present; mesial margin crenulated, otherwise smooth. Palp shorter than the merus; carpus compressed, longer, ornamented with small tubercles dorsally, few long setae on lateral margin; propodus, dactylus cylindrical, similar in size, without tubercles, with long setae along mesial, lateral margins; propodus slender.
Male thoracic sternite III broadly triangular, with 3 acute tubercles in the anterior tip, sparse tubercles irregularly distributed. In males, sternite IV strongly sloping down in ventral view, sparsely covered with tubercles, sterno-abdominal cavity longer than telson, leaving gap between telson, anterior crenulated margin. Male sternites V–VII with strong tubercles, surface in females smooth. Episternites IV–VII with crenulated margins.
Chelipeds equal, distinctly long, robust in males, females with shorter, more slender chelipeds. Palm, fingers compressed laterally. Row of tubercles in lateral margin forming carina, smaller tubercles sparsely distributed; mesial margin forming distinct carina. Dactylus, fixed finger distinctly shorter than palm, cutting edges with subequal teeth; in males, fingers leaving strong gap in proximal half when closed, dactylus with small, blunt, distinct basal tooth, absent in females. Movable, fixed fingers smooth on mesial, lateral faces, inconspicuous carina on lateral face of dactylus. Carpus, merus, ischium densely covered with tubercles. Merus with row of stronger tubercles on mesial face, short hooked setae present.
Walking legs slender, cylindrical. First leg longest. Dactylus slightly curved, densely setose, with small granules on lower edge. Propodus, carpus, merus, ischium with subequal tubercles evenly distributed.
Male abdominal somites 1–6, telson free, slightly raised medially forming low longitudinal ridge. Female abdominal somites 1–3, telson free, 4–6 fused. In males, surface of abdominal segments 1–6, in females, 1–3 covered with distinct tubercles, female fused somites with tubercles concentrated in the proximal half. Female abdomen markedly arched, with row of setae on margin. Telson subtriangular, terminating in rounded apex in males, with few tubercles; female telson transversally oval, without tubercles. Gonopod 1 (= male pleopod 1) stout, straight, slightly converging, with acute apex on lateral margin; mesial lobe long, acute, upturned, with aperture forming distinct groove. Distinct velvet on lateral margin in distal third. Gonopod 2 (= male pleopod 2) slender, straight, very short (one fifth of G1 length).
Type locality. Cape Guardafui, Somali Republic, 11°24’N- 51°35’E, 75–150 m of depth.
Distribution. Known so far only from the type locality.
Etymology. The specific epithet is derived from the Greek adjective kallistos for “the most beautiful.”
Remarks. Sunipea callistus n. sp. is easily distinguishable from S. indicus by (i) a carapace that is uniformly and densely covered with subequal tubercles (Figs. 1A, 2A, 3A) (carapace with subequal tubercles irregularly distributed and concentrated in some regions in S. indicus; Figs. 1B, 2B, 3B); (ii) rostrum straight (Figs. 1A, 2A, 3A) (rostrum curved, divergent in S. indicus; Figs. 1B, 2B, 3B); (iii) ocular peduncle with sharp tubercles distally (Figs. 1A, 3A) (ocular peduncle with a distinct anterior lamella in distal half in S. indicus; Figs. 1B, 3B); (iv) third and fourth antennal articles that reach the rostrum length (Fig. 3A) (third and fourth antennal articles do not reach the tip of the rostrum in S. indicus; Fig. 3B); (v) epistome without tubercles (Figs. 1C, 2C) (with a few distinct tubercles in S. indicus; Figs. 1D, 2D); (vi) the merus of the third maxillipeds with a distinct crenulated anterior margin that ends in a spine medially and a mesial crenulated margin (Fig. 4 C) (the merus of the third maxillipeds are without an anterior crenulated margin and a medial spine, with a crenulated anterolateral angle and mesial margin that contains a few small sharp tubercles in S. indicus; Fig. 4 D); (vii) sparse small tubercles that are irregularly distributed in thoracic sternite III (Figs. 1C, 2C, 3 C) (verrucose tubercles in S. indicus; Figs. 1D, 2D, 3 D); (viii) male thoracic sternites IV–VII with tubercles irregularly distributed (Figs. 1C, 3 C) (the strong verrucose tubercles form carinas in S. indicus; Figs. 1D, 3 D); (ix) the male sterno-abdominal cavity is longer than the telson, thus leaving a gap between the telson and the anterior crenulated margin (Figs. 1C, 3 C) (the sterno-abdominal cavity encircles the telson, forming a keen carina with two distinct tubercles on each side of the telson in S. indicus; Figs. 1D, 3 D); (x) the chelipeds of the males with a distinct gap between the fingers in the proximal half (Fig. 4 E) (chelipeds without gap in S. indicus; Fig. 4 F); (xi) the female abdominal somites 1–3 only have tubercles (Figs. 2C, 4A) (female abdominal somites 2–6 are covered with tubercles in S. indicus; Figs. 2D, 4B); (xii) the female telson is without tubercles (Figs. 2C, 4A) (the female telson is covered with tubercles in S. indicus; Figs. 2D, 4B); and (xiii) the male gonopod 1 is straight and slightly converging, with mesial lobe acute, upturned, forming a distinct groove, and the lateral margin has a distinct velvet in the distal third (Figs 5 A, B) (gonopd 1 slightly curved, divergent, with mesial lobe leaf-like, directed anteromesially, with a large aperture and the distinct velvet on lateral margin absent in S. indicus; Figs 5 C, D).
Although several characters can be diagnostic between the two species, these differences are much more noticeable in males than females. For example, the difference in the width of the carapace, which is noticeably wider in males of S. callistus n. sp. than in S. indicus, is much less evident in females (Fig. 2). Also, differences in the rostrum, chelipeds and abdomen of the females of both species are not as noticeable as in males (Figs 2, 4A, B). This may be why Griffin (1974: 7) identified the present material as S. indicus. Griffin (1974: 7) treated the differences he observed in the rostrum as only morphological variation, commenting that “the rostral spines are sometimes straight and sometimes outwardly curved” (see also Griffin & Tranter 1974: 165). There is no mention about the other differences that are listed, although he observed that some specimens did not possess intact gastric and cardiac spines (Griffin & Tranter 1974). The similarities of the females and the fact that carapace spines, including the rostrum, are frequently broken and sometimes resemble blunt tubercles could also be misleading. Griffin & Tranter (1984: 59) also described the interantennular partition as without a spine for the genus. In the material studied, however, all specimens of both species had an interantennular septum that had a distinct ventrally directed lobe. Other than that, the description presented here agrees with the description of the genus presented by Griffin & Tranter (1984).
Alcock (1895: 189) described Apocremnus indicus on the basis of two specimens, a male of 9 mm cl and a female 6 mm cl, without indicating which was the holotype. Davie (2002: 298) mentioned that the syntypes are deposited in the Indian Museum, the present Zoological Survey of India (ZSI). This material was not available for me to study, thus, although needed, no inference about lectotypes can be made.
description: Published as part of Santana, William, 2015, A new species of Sunipea Griffin & Tranter, 1986 (Crustacea: Brachyura: Inachidae) and a redescription of Sunipea indicus (Alcock, 1895), pp. 383-393 in Zootaxa 4052 (3) on pages 390-392, DOI: 10.11646/zootaxa.4052.3.8, http://zenodo.org/record/244868