Homologenus brevipes, Ng & Forges, 2017

Ng, Peter K. L. & Forges, Bertrand Richer de, 2017, On a collection of Homolidae from the South China Sea, with descriptions of two new species of Homologenus A. Milne-Edwards, in Henderson, 1888, and the identities of Homologenus malayensis Ihle, 1912, and Lamoha superciliosa (Wood-Mason, in Wood-Mason & Alcock, 1891), Raffles Bulletin of Zoology 65, pp. 243-268 : 261-266

publication ID	https://doi.org/ 10.5281/zenodo.5356049
publication LSID	lsid:zoobank.org:pub:CC246EF9-E704-4DDC-BD25-61B6102A382F
persistent identifier	https://treatment.plazi.org/id/DBF032F7-7DCC-4972-8AAF-FED4E0ACA58E
taxon LSID	lsid:zoobank.org:act:DBF032F7-7DCC-4972-8AAF-FED4E0ACA58E
treatment provided by	Valdenar
scientific name	Homologenus brevipes
status	sp. nov.

Treatment

Homologenus brevipes View in CoL n. sp.

( Figs. 16 View Fig , 17 View Fig , 18G–I View Fig , 19I–P View Fig , 20F–H View Fig , 21G–I View Fig , 22D–F View Fig )

Homologenus malayensis View in CoL – Ho et al., 2004: 642, fig. 1A. – Ahyong et al., 2009: 86, fig. 54, 55. (not Homologenus malayensis Ihle, 1912 View in CoL )

Material examined. Holotype: ovigerous female (15.0 × 10.7 mm) ( NTOU), station PCP 344, 22°15.95′N 120°0.11′E, 995–1073 m, southern Taiwan, trawl, coll. TAIWAN 2006 Cruise , 8 March 2006 GoogleMaps . Paratypes: 1 ovigerous female (14.8 mm, rostrum broken) ( ZRC 2013.0298 View Materials ), station PCP 344, 22°15.95′N 120°0.110′E, 995–1073 m, coll. TAIWAN 2006 Cruise , 8 March 2006 GoogleMaps . – 1 ovigerous female (16.8 × 15.0 mm) ( ZRC 2009.1161 View Materials ), station CP 141, 22°12.04′N 119°59.96′E, 985–1110 m, eastern Taiwan, trawl, TAIWAN 2001 Cruise , 24 November 2001 GoogleMaps . – 1 male (12.7 × 10.0 mm) ( ZRC 2009.1162 View Materials ), station CD 136, 22°7.75′N 120°0.87′E, 998–1211 m, eastern Taiwan, trawl, coll. TAIWAN 2001 Cruise , 22 November 2001 GoogleMaps . – 3 ovigerous females (17.0 × 15.0 mm, 17.4 × 14.3 mm, 16.8 × 13.9 mm) ( ZRC 2009.1160 View Materials ), station CP 134, 22°16.56′N 120°6.11′E, 736–1040 m, eastern Taiwan, trawl, coll. TAIWAN 2001 Cruise , 22 November 2001 GoogleMaps . – 1 ovigerous female (15.4 × 13.5 mm) ( ZRC 2016.0572 View Materials ), station CD 192, 22°17.19′N 120°1.01′E, 960–1302 m, southern Taiwan, trawl, coll. TAIWAN 2002 Cruise , 28 August 2002 GoogleMaps . – 1 ovigerous female (13.8 × 10.2 mm) ( ZRC 2016.0573 View Materials ), station PCP 445 ( NTOU B00069), 22°17.10′N 120°0.17′E, 982–999 m, southern Taiwan, trawl, coll. TAIWAN 2006 Cruise , 14 July 2008 GoogleMaps . – 1 ovigerous female (12.4 × 9.9 mm, broken rostrum), 1 male (7.6 × 5.9 mm) ( ZRC 2016.0574 View Materials ), southern Taiwan, 22°17.17′N 120°00.18′E – 22°13.24′N 120°00.32′E, coll. trawl, 5 July 2013 GoogleMaps . – 1 ovigerous female (16.1 × 10.9 mm) ( ZRC 2016.0575 View Materials ), station OCP 280, 24°23.71′N 122°14.22′E, 1213–1261 m, eastern Taiwan, trawl, coll. TAIWAN 2005 Cruise , 14 June 2005 GoogleMaps .

Diagnosis. Small species, covered with numerous long and short setae ( Fig. 16 View Fig ). Carapace longer than wide; male carapace longitudinally ovate; anterior half of female carapace distinctly less wide than posterior half; surface of carapace granular; gastro-cardiac and branchio-cardiac grooves well marked; with short, sharp median gastric spine and 2 short epigastric spines; short spine at angle of buccal cavity; line of prominent granules marking border of pterygostomian region ( Figs. 16 View Fig , 17A View Fig , 18G–I View Fig ). Rostrum very long, curved, sharp, with 2 short accessory pseudorostral spines pointing anteriorly ( Figs. 16 View Fig , 17A, B View Fig , 18G–I View Fig ). Well-developed pseudorostral spines in supra-ocular position almost straight, directed obliquely anteriorly; supraorbital margin with short spine ( Figs. 16 View Fig , 17A, B View Fig , 18G–I View Fig ). Basal antennal spine strong ( Fig. 17A View Fig ). Subhepatic spine slender ( Fig. 17A View Fig ). Anterolateral spine long, sharp, pointing obliquely outwards, relatively more anteriorly in angle ( Figs. 16 View Fig , 17A View Fig , 18G–I View Fig ). Anteroexternal angle of merus of third maxilliped with 1 sharp curved spine ( Fig. 17C View Fig ). Female cheliped short; chela slightly inflated: chela with 5 small spines on ventral margin and 4 spines on dorsal margin; fingers long, slender, curved inwards; carpus with 3 long spines on external face; merus with 8 strong spines on outer margin and 6 spines on inner margin ( Fig. 17D, E View Fig ). Male cheliped short; chela inflated, triangular in cross-section, fingers closely appressed when closed; margins of merus spinose; carpus with 4 prominent spines; dorsal margin of chela with 4 spines, ventral margin with 4 spines ( Fig. 21I View Fig ). Ambulatory legs (P2–P4) long, slender; P5 reduced, in dorsal position, merus unarmed, not reaching base of anterolateral spine when folded on carapace; dactylus long, relatively wider, curved, sharp, reaching proximal spine of propodus, forming pseudochela ( Figs. 16 View Fig , 19L, P View Fig , 20F–H View Fig ); female: P2 merus with 3 spines on dorsal margin, outer surface with 2 or 3 spinules, ventral margin with 3 or 4 spinules; P3 merus with 2 or 3 spines on dorsal margin, outer surface with 1 spinule, ventral margin with 4 spines; P4 merus with 3 spines on dorsal margin, outer surface with 2 spinules, ventral margin with 2 spines ( Figs. 16A, B View Fig , 19I–K View Fig ); male: P2 merus with 4 or 5 spines on dorsal margin, outer surface with 2 spinules, ventral margin with 4 or 5 spinules; P3 merus with 4 spines on dorsal margin, outer surface with 2 spinules, ventral margin with 5 or 6 spinules; P4 merus with 4 spines on dorsal margin, outer surface with 2 spinules, ventral margin with 4 spines ( Figs. 16C View Fig , 19M–O View Fig ); P2–P4 propodus long, dactylus long, falciform ( Fig. 16 View Fig ). Armature of pleonites as follows: female somite 2 with 1 median spine, somite 3 with 4 low spines, somite 4 with 4 very low spines, somite 5 with 4 very low spines, telson, somites 1, 5 and 6 unarmed ( Fig. 17F View Fig ); male somite 2 with 1 median spine, somite 3 with 5 low spines, somite 4 with 4 low spines, somite 5 with 4 low spines, telson, somites 1 and 6 unarmed ( Fig. 21G, H View Fig ). G1 relatively stout, distal part tapering to cone-like structure ( Fig. 22D, E View Fig ).

Etymology. The name alludes to the relatively shorter ambulatory legs of this species when compared to those of the allied new species, H. exilis . Used as a noun in apposition.

Colour. The specimen illustrated in colour by Ahyong et al. (2009: 86, fig. 54) is the present holotype of H. brevipes . In life, the carapace is dirty white overall with the anterior part of the carapace pink.

Remarks. As discussed earlier, there are several differences between H. brevipes n. sp. and H. malayensis Ihle, 1912 . The most significant is in the ventral margin of the P4 merus in H. brevipes n. sp. possessing two spines ( Fig. 19K, O View Fig ) (margin unarmed in H. malayensis , Figs. 8B View Fig , 12G, K View Fig ). In addition, the rostrum of H. brevipes is relatively shorter ( Fig. 16 View Fig , 17B View Fig , 18G–I View Fig ) (rostrum distinctly longer in H. malayensis , Figs. 8A, F View Fig , 9 View Fig , 10, 11B View Fig , 18A, B View Fig ); and the pseudorostral spines are almost straight and directed anterolaterally ( Figs. 17B View Fig , 18G–I View Fig ) (gently curving laterally in H. malayensis , Figs. 8A, F View Fig , 9 View Fig , 10, 11B View Fig , 18A, B View Fig ).

In addition to the difference in carapace shape and armature of the P4 merus discussed above, male H. brevipes can be separated from H. donghaiensis (known only from one male) in having the spines on the dorsal margin of P2–P4 straight ( Fig. 19I–K, M–O View Fig ) (spines are curved backwards in H. donghaiensis , Fig. 13A–C View Fig ); the male has only five spines on the dorsal margin of the P2 merus ( Figs. 16A View Fig , 19I, M View Fig ) (with only 3 or 4 spines in male H. donghaiensis , Fig. 13A, B View Fig ); the spines on pleonal somites 2 and 3 are low but distinct ( Fig. 17F View Fig ) (very short or not visible in H. donghaiensis, Ng & Chen, 1999 : fig. 3g); and the dactylus of P5 reaches to the subproximal spine of the propodus ( Fig. 20F–H View Fig ) (P5 dactylus relatively shorter, not reaching the subproximal propodal spine in H. donghaiensis , Fig. 13A, B View Fig ; Ng & Chen, 1999: fig. 3e).

The female specimen reported and figured as “ H. malayensis ” in Ho et al. (2004: fig. 1A) from southern Taiwan could not be examined but the colour figure leaves no doubt it is conspecific with H. brevipes .