Caecopilumnus crassipes ( Tesch, 1918 )

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2014, Revision of the family Acidopsidae Števčić, 2005, and the systematic position of Typhlocarcinodes Alcock, 1900, Caecopilumnus Borradaile, 1902, and Raoulia Ng, 1987, with descriptions of two new genera and five new species (Crustacea: Brachyura: Goneplacoidea), Zootaxa 3773 (1), pp. 1-63 : 42-47

publication ID	https://doi.org/ 10.11646/zootaxa.3773.1.1
publication LSID	lsid:zoobank.org:pub:19F28753-B2D0-4D1F-9D47-88886F7333FD
DOI	https://doi.org/10.5281/zenodo.5047768
persistent identifier	https://treatment.plazi.org/id/03E287AE-546C-E215-8A9D-448EFAAC0A1C
treatment provided by	Felipe
scientific name	Caecopilumnus crassipes ( Tesch, 1918 )
status

Treatment

Caecopilumnus crassipes ( Tesch, 1918)

( Figs. 1E, F View FIGURE 1 , 4C, D View FIGURE 4 , 5I View FIGURE 5 , 6D View FIGURE 6 , 28–31 View FIGURE 28 View FIGURE 29 View FIGURE 30 View FIGURE 31 , 41C View FIGURE 41 )

Typhlocarcinoides crassipes Tesch, 1918: 230 , pl. 15 fig. 1.— Balss 1938: 73.— Sakai 1955: 109, text-fig. 5.— Serène 1968: 92.— Sakai 1976: 550, text-fig. 297.

Caecopilumnus crassipes — Ng 1987: 91.— Ng et al. 2008: 143.

Material examined. Holotype: male (7.9 × 6.3 mm) ( ZMA 103.006 ), station 225c, reef, Lucipara I., Banda Sea, Indonesia, coll. SIBOGA Expedition, July 1899.

Others — Indonesia: 1 male (11.8 × 10.1 mm) ( ZRC 2013.1710 View Materials ), Kecinan, western Lombok , Lesser Sunda Island , 0824.368'S 11603.561'E, sand with seagrass, 0–1 m, coll. D.L. Rahayu et al., 15 May 2007 ; 2 males (12.9 × 11.4 mm, 5.5 × 4.2 mm) ( ZRC 2013.1711 View Materials ), 1 male (11.1 × 9.5 mm), 1 female (13.0 × 11.0 mm) ( MZB Cru 3915), intertidal areas, Sira, northern Lombok , Lesser Sunda Island , 0821.641'S 11606.272'E, coll. D.L. Rahayu et al., 13 June 2007 ; Japan: 1 male (9.0 × 7.8 mm) ( ZRC 2013.0410 View Materials ), Okinawa, Runigami, Yona , coll. T. Maenosono, 17 April 2010 ; 1 ovigerous female (12.3 × 10.7 mm) ( ZRC 2013.0411 View Materials ), Sesoko , Okinawa, coll. T. Maenosono, 7 Jun 2009 ; 1 female (5.3 × 4.5 mm) ( SMF 37785), March 1979 .

Diagnosis. Carapace subovate; dorsal surface finely granular; regions separated by relatively shallow grooves ( Figs. 28A View FIGURE 28 , 29A View FIGURE 29 , 30 View FIGURE 30 ). Anterolateral margin arcuate, granular, with low granuliform lobes, sometimes not discernible ( Figs. 28A View FIGURE 28 , 29A View FIGURE 29 , 30 View FIGURE 30 ). Merus of third maxilliped prominently rounded ( Figs. 5I View FIGURE 5 , 28B View FIGURE 28 , 31B View FIGURE 31 ). Merus of last ambulatory leg 1.5 times as long as broad; propodus ovate, as long as broad ( Figs. 28C View FIGURE 28 ). Male abdomen relatively narrower; a1 with lateral margins gently convex or subtruncate; a3–6 proportionately narrower ( Fig. 31A View FIGURE 31 ). Gl stout, gently sinuous, proximally dilated, tip narrow, lateral, mesial margin with row of spinules, outer, inner surface with scattered spinules ( Fig. 31D–F View FIGURE 31 ). G2 as long as G1; distal segment half length of basal segment ( Fig. 31G View FIGURE 31 ).

Re-description. Carapace subovate; dorsal surface convex, finely, evenly granular, setose; regions separated by distinct shallow grooves ( Figs. 28A View FIGURE 28 , 29A View FIGURE 29 , 30 View FIGURE 30 ). Front relatively wide, entire, prominently deflexed, margin gently convex ( Figs. 28A View FIGURE 28 , 29A, C View FIGURE 29 , 30 View FIGURE 30 ). Anterolateral margin arcuate, granular, hirsute, with 2 or 3 low, sometimes indistinct lobes which are lined with granules of varying size; barely separated from posterolateral margin ( Figs. 28A View FIGURE 28 , 29A View FIGURE 29 , 30 View FIGURE 30 ). Posterolateral margin almost straight or gently convex, distinctly converging towards posterior carapace margin ( Figs. 28A View FIGURE 28 , 29A View FIGURE 29 , 30 View FIGURE 30 ). Posterior carapace margin gently concave ( Figs. 28A View FIGURE 28 , 29A View FIGURE 29 , 30 View FIGURE 30 ). Epistome narrow, prominently sunken ( Fig. 29C View FIGURE 29 ). Basal antennal article transversely rectangular, distinctly wider than long; article 3 longer than wide; article 4 distinctly dorsoventrally flattened, twice as long as broad, margins with numerous long plumose setae ( Figs. 6D View FIGURE 6 , 31C View FIGURE 31 ). Eye immobile, completely filling ovate orbit; short, pear-shaped, tapering to small cornea that has a tiny dot of pigmentation; peduncle stout ( Figs. 29C View FIGURE 29 , 31C View FIGURE 31 ).

Third maxillipeds relatively short, stout, leaving narrow gap when closed; ischium rectangular, 1.6 times length of merus, with shallow sublateral sulcus; merus rounded, anterolateral angle strongly convex; exopod relatively narrow, reaching to midlength of merus, with long flagellum ( Figs. 5I View FIGURE 5 , 28B View FIGURE 28 , 31B View FIGURE 31 ).

Chelipeds subequal, long setae on upper, lower margins of chela, carpus, merus; almost entire surface of outer surface of chela covered by large tubercles, short setae; fingers shorter than palm; dactylus curved, cutting edges with distinct teeth, denticles ( Figs. 28A, D, E View FIGURE 28 , 29A, E, F View FIGURE 29 , 30 View FIGURE 30 ).

Ambulatory legs relatively short, third leg longest; dorsal, ventral margins of ambulatory legs fringed with long setae; merus of last leg 1.5 times as long as broad; propodus of fourth leg subovate, narrow distally, becoming wider proximally, as long as broad; dactylus of fourth leg longer than propodus ( Figs. 28A, C View FIGURE 28 , 29A View FIGURE 29 , 30 View FIGURE 30 ).

Male thoracic sternum narrow; st1, 2 completely fused to form triangular plate, st3 separated from st2 by narrow, shallow, suture; st3, 4 fused with only lateral sutures discernible, medially depressed; sutures 4–7 complete, st8 short, separated from st7 by short, shallow suture; penis coxo-sternal, emerging from cx5, under overlapping parts of st7, 8, then entering exposed short groove between st7, 8 towards sterno-abdominal cavity ( Figs. 1E, F View FIGURE 1 , 29B View FIGURE 29 ). Sterno-abdominal cavity deep; press-button mechanism for holding male abdomen present as small rounded tubercle on posterior third of st5 ( Fig. 1F View FIGURE 1 ).

Male abdomen with a1 wide, broad, subrectangular, lateral side almost straight, reaching to cx5; a3–5 fused, sutures visible medially, laterally, usually incomplete; a3 expanded laterally to form triangular plate, covering most of penis when closed; a6 rectangular, lateral sides slightly concave; telson triangular, broader than long, tip rounded ( Figs. 1E View FIGURE 1 , 29D View FIGURE 29 , 31A View FIGURE 31 ).

Gl stout, gently sinuous, proximally dilated, distal half slightly more slender than proximal, tip narrow, subtruncate, lateral, mesial margin with numerous spinules, outer, inner surface with scattered spinules ( Fig. 31D– F View FIGURE 31 ). G2 as long as G1; distal segment half length of basal segment ( Fig. 31G View FIGURE 31 ).

Chelipeds of female with relatively larger, denser tubercles on outer surface of chela ( Fig. 28D, E View FIGURE 28 ). Female abdomen relatively narrow, all somites, telson free ( Figs. 4C View FIGURE 4 , 31H View FIGURE 31 ); vulvae subovate, with operculum ( Fig. 4D View FIGURE 4 ).

Colour. In life, specimens from Lombok and Okinawa are dirty white to cream, sometimes with faint patches of light brown or grey on the dorsal surface of the carapace ( Fig. 41C View FIGURE 41 ).

Remarks. The figure in Tesch (1918: 230, pl. 15 fig. 1) and his description of the anterolateral margin is not accurate. The anterolateral margin was described and figured as almost entire without lobes or notches, but the holotype female actually possesses low but discernible granulated lobes ( Fig. 28A View FIGURE 28 ).

Tesch (1918: 227) doubted that C. crassipes “has a right of existence” because he only had a female specimen, and could be separated from C. hirsutus by the setae on the front being relatively longer than those laterally, the granules on the carapace being smaller and the grooves more shallow and less distinct, as well as the shorter and more rounded form of the last ambulatory propodus ( Tesch 1918: 228, 230–231). Compared to C. hirsutus , the setae on the front of C. crassipes are generally longer than that on the anterolateral margin, but with only two known specimens of C. hirsutus examined, this is a character of doubtful value. The dorsal carapace characters (relatively weaker granulation and less prominent grooves) are useful, being relatively constant in the series of specimens of C. crassipes examined. While it varies somewhat, from the condition seen in the type female and others (e.g., Figs. 28A View FIGURE 28 , 30 View FIGURE 30 ) to being more granular with somewhat deeper and more prominent grooves (e.g., Fig. 29A View FIGURE 29 ), they are invariably weaker than those in C. hirsutus ( Figs. 25A View FIGURE 25 , 26A View FIGURE 26 ). The form of the ambulatory propodus is reliable, being consistently more ovate and shorter, and easily distinguishes males and females of C. crassipes from congeners (including C. loculatus sp. nov.) ( Fig. 28C View FIGURE 28 versus Figs. 25C View FIGURE 25 , 26C View FIGURE 26 , 32A View FIGURE 32 ).

The strength of the lobes and degree of granulation on the anterolateral margin of carapace varies somewhat, mainly with size. A small specimen from Lombok (5.5 × 4.2 mm, ZRC 2013.1711) has the three anterolateral lobes relatively more prominent with strong spine-like granules. In the male specimen from Japan (9.0 × 7.8 mm, ZRC 2013.0410), the granules are larger but it does not form very distinct lobes ( Fig. 30C View FIGURE 30 ), while large specimens from Lombok (female, 13.0 × 11.0 mm, MZB; male, 12.9 × 11.4 mm, ZRC 2013.1711), the lateral margin is almost entire, lined with large and small tubercles, and the carapace appears somewhat longer ( Fig. 30B View FIGURE 30 ).

We do not have much doubt about the female specimen reported as “ T. crassipes ” by Sakai (1955, 1976) from the Bonin Is. (= Ogasawara Is.) (collection depth not stated). His description and figure agrees well with our material from the Ryukyus in Japan.

Distribution. Lombok and Maluku ( Indonesia), and Okinawa and Ogasawara Is. ( Japan); intertidal.