Gonodactylellus kume, Ahyong Kumejima, 2012

Ahyong Kumejima, Shane T., 2012, Stomatopod Crustacea of the KUMEJIMA 2009 Expedition, Japan *, Zootaxa 3367, pp. 232-251 : 235-239

Gonodactylellus kume sp. nov. *#

( Fig. 2B–F, 3)

Gonodactylus incipiens . — Moosa, 1991: 158 [part, not G. incipiens ( Lanchester, 1903) ].

Gonodactylellus micronesicus . — Ahyong 2001: 57, fig. 27A–I [part, Indian Ocean and Lizard Island specimens only]; 2007: 334. [Not G. micronesicus ( Manning, 1971) ]

Type material. HOLOTYPE: RUMF-ZC-01262, male (TL 22 mm), 26° 19.449 –19.478´N, 126° 45.748 –45.800´E, 8.9–9.3 m, dead coral branches, rubble, dredge 51, 16 Nov 2009. PARATYPES: RUMF-ZC-01272, 1 male (TL 17 mm), 26° 19.449 –19.478´N, 126° 45.748 –45.800´E, 8.9–9.3 m, dead coral branches, rubble, dredge 51, 16 Nov 2009; RUMF-ZC-01258, 1 female (TL 19 mm), Umagai, 26°20.769´N, 126°51.506´E, 5–50 m, Dive 1, 9 Nov 2009; RUMF-ZC-01259, 1 male (TL 17 mm), Nanguchi, 26°18.536´N, 126°50.402´E, <25 m, dead coral rubble, reef-end, dive 8, 11 Nov 2009; RUMF-ZC-01260, 1 male (TL 19 mm), 1 female (TL 20 mm), 26° 18.330 –18.351´N, 126° 49.730 –49.734´E, 27–28 m, 27–28 m, trawl 15, 11 Nov 2009; RUMF-ZC-01261, 1 female (TL 19 mm), Umagai, 26°20.769’N, 126°51.506’E, 55 m, dive 1b, 9 Nov 2009; RUMF-ZC-01267, 1 male (TL 16 mm), Tengokuto-Zigoku, 26°19.421´N, 126°45.733´E, 6–8 m, dive 37, 19 Nov 2009; AM P87563, 2 males (TL 15–21 mm), 26° 19.714 –19.579´N, 126° 45.649 –45.707´E, 17.9–42.5 m, rubble, dredge 44, 14 Nov 2009 ; RUMF-ZC-01263, 1 female (TL 16 mm), 26° 19.502 –19.494´N, 126° 45.570 –45.796´E, 50– 11.4 m, dead coral branches, rubble, dredge 49, 16 Nov 2009; ZRC 2011.0824 , 1 male (TL 17 mm), 1 female (TL 14 mm), 26° 19.517 –19.513´N, 126° 45.797 –45.782´E, 9.6–13.2 m, dead coral branches, rubble, dredge 50, 16 Nov 2009 ; AM P87564, 1 female (TL 21 mm; with gastropod Caledoniella and rhizocephalan parasites), Imazuni, 53 m, SCUBA, 10 Nov 2009 .

Other material. AUSTRALIA: AM P84085, 1 male (TL 16 mm), Wall of Fish, Yonge Reef, outer Great Barrier Reef, Queensland, 14°34.8’S, 145°37.2’E, 27 m, coral rubble, coll. M. Porter et al., 2 Jun 2010; WAM C45805, 1 female (TL 22 mm), Cassini, 13°57.094’S, 125°37.447’E, 2 m, st. 37/K10- T 4, coll. Skipton, 18 Oct 2010. PAPUA NEW GUINEA: AM P64464, 1 female (TL 18 mm, with gastropod Caledoniella ), Horseshoe Reef, Bootless Inlet, 9°30.5’S 147°15.5’E, base of reef slope, outer face, coral rubble with some Padina , 30 m, PNG-21, coll. S. Arnam & J. Lowry, 28 Oct 1980; AM P64468, 1 female (TL 15 mm), north end of Kiriwinna Island, Papua New Guinea, poison station, coll. Collette, Goldman & Palmer, 7 Jun 1970. SOLOMON ISLANDS: AM P64465, 1 male (TL 10 mm), between Tandai & Koilo Points, Guadalcanal, Solomon Islands, 09°22.5'S 159°52.2'E, airlift over small encrusted coral heads on grey sand, 15 m, SI-2, coll. R. Springthorpe 24 Sep 1991.

Diagnosis. Ocular scales separate, subtriangular, apices rounded. Rostral plate basal portion anterolateral angles rounded; lateral margins divergent anteriorly. Raptorial claw dactylus without proximal notch in adults. Thoracic somite 6 lateral processes truncate ventrally, wider than that of thoracic somite 7. Pleopod 1 endopod with indistinct lateral lobe on posterior endite; lateral lobe narrow, small, margin continuous with or hardly breaking from general outline of distal ‘endite’. Telson surface without dorsal spinules; intermediate teeth apices extending posteriorly well beyond apices of intermediate denticles; intermediate carina extending anteriorly beyond midlength of accessory median carina; emargination between submedian and intermediate teeth acute; lateral teeth indicated by a shallow notch; median carina with small posterior tubercle or spinule, otherwise unarmed dorsally; accessory median carinae unarmed, extending anteriorly to about midlength of median carina or to posterior onethird in males with inflated median carina; anterior submedian carinae extending anteriorly as far as base of median carina; knob present.

Description. Eyes elongate; cornea subconical. Ocular scales separate, subtriangular, apices rounded. Antennular peduncle length 0.63–0.73 CL. Antennal scale length 0.38–0.42 CL.

Rostral plate as long as wide or longer than wide; basal portion with transverse or slightly sloping posteriorly; anterolateral angles rounded; lateral margins divergent anteriorly; median spine longer than base, without ventral keel.

Raptorial claw dactylus without proximal notch on outer margin in adults; propodus with proximal movable spine, opposable margin sparsely pectinate proximally.

Mandibular palp 3-segmented.

Thoracic somite 6 lateral processes truncate ventrally, wider than that of thoracic somite 7. Thoracic somite 8 anterolateral margin rounded; sternal keel obsolete.

Pleopod 1 endopod with indistinct lateral lobe on posterior ‘endite’; lateral lobe narrow, small, usually evenly rounded (obtusely angular in holotype), margin continuous with or hardly breaking from general outline of distal ‘endite’, demarcated at most by small notch.

Abdominal somite 1–5 posterolateral angles unarmed. AWCLI 688–752. Abdominal somite 6 with posteriorly armed submedian, intermediate and lateral bosses.

Telson as wide as or wider than long, surface without dorsal spinules; with 10–14 spiniform submedian denticles. Submedian teeth unarmed dorsally, dorsal carina relatively slender. Intermediate teeth distinct, apices sharp, extending posteriorly well beyond apices of intermediate denticles; intermediate carina slender, extending anteriorly beyond midlength of accessory median carina; emargination between submedian and intermediate teeth acute. Lateral teeth indicated by a shallow notch, apex angular to blunt, not projecting well off margin of telson. Median carina more strongly inflated in males than in females; with small posterior tubercle or spinule, otherwise unarmed dorsally. Accessory median carinae unarmed, extending anteriorly to about midlength of median carina or to posterior one-third in males with inflated median carina. Anterior submedian carinae smooth, unarmed, straight or slightly arcuate, extending anteriorly as far as base of median carina. Knob present. Telson ventral surface without carinae on submedian or intermediate teeth.

Uropodal protopod terminal spines with outer spine longer. Uropodal exopod proximal segment outer margin with 9–11 movable spines, distalmost spine exceeding apex of distal segment; inner margin setose; distal margin with ventral spine; exopod distal segment rounded, entire margin setose. Uropodal endopod narrow, length 3.29–3.71 breadth; with low dorsolateral carina; entire margin setose.

Colour in life. ( Fig. 2B–F) Overall body colour variable, ranging from mottled pale green to red. Raptorial claw dactylus pink-orange; meral spot red.

Measurements. Males (n = 10) TL 10–22 mm, females (n = 9) TL 14–22 mm. Other measurements of holotype: CL 4.6 mm, antennular peduncle 3.1 mm, antennal scale 1.8 mm, abdominal somite 5 width 3.2 mm.

Etymology. Named after the expedition and type locality, Kume; used as a noun in apposition.

Remarks. Prior to this study, Gonodactylellus Manning, 1995 , contained 21 species from the Indo-West Pacific ( Ahyong 2001, 2008, 2012; Ahyong & Erdmann 2007). Gonodactylellus kume sp. nov. most closely resembles G. micronesicus ( Manning, 1971) and G. rubriguttatus Erdmann & Manning, 1998 , sharing unarmed accessory median carinae on the telson, which extend anteriorly to near the midlength of the median carina. The separate instead of fused ocular scales distinguish G. kume and G. micronesicus from G. rubriguttatus . The red instead of white meral spot of the raptorial claw distinguishes G. kume and G. rubriguttatus from G. micronesicus . Male G. kume differ from both G. micronesicus and G. rubriguttatus in having an indistinct lobe on the outer margin of the distal ‘endite’ of the pleopod 1 endopod. The lateral lobe in G. kume is narrow, with its margin continuous with or hardly breaking from the general outline of the distal ‘endite’ (demarcated at most by small notch; Fig. 3J, M)), rather than projecting laterally as a prominent flap (strongly demarcated by a deep notch) as in G. rubriguttatus and G. micronesicus (see Ahyong 2001: 29 J; 2002a: fig. 3F). Whilst both sexes of G.kume differ from G. rubriguttatus by the separate instead of fused ocular scales, specimens of female G. kume in which the colour is faded will be difficult to distinguish from G. micronesicus .

As in other species of Gonodactylellus , the telson carinae of adults are sexually dimorphic. Telson carinae in females and early adult males are relatively slender, whereas those of large males are more inflated, with the median carina tumid, largely obscuring the accessory median carinae. In these large males, the anterior ends of the accessory median carinae are subsumed by the median carina and thus reach anteriorly only as far as the posterior one-third instead of the midlength of the median carina. Males in the present series range from TL 10–21 mm; all have fully developed penes and modified pleopod 1 endopods. The proximal notch on the outer margin of the dactylus of the raptorial claw is distinct in juveniles, faint or indistinct by TL 15 mm, and absent above TL 15 mm. Two females (TL 18 mm, AM P64464; TL 21 mm, AM P87564) are parasitized by the gastropod mollusc, Caledoniella montrouzieri Souverbie, 1869 .

Records of G. micronesicus from Western Australia, the Cocos-Keeling Islands and New Caledonia ( Ahyong 2001, 2007) are referrable to G. kume sp. nov. Queensland specimens reported by Ahyong (2001) as G. micronesicus are referrable to two species: G. kume (Lizard Island specimens) and an undescribed species of Gonodactylellus currently under study (non-Lizard Island specimens). This revised distribution of G. micronesicus suggests that the species favours oceanic island habitats in the central-western to central Pacific, from Micronesia, Guam and French Polynesia. In contrast, G. kume occurs along the western margins of the western Pacific (between Japan and Australia) to the eastern Indian Ocean (between northwestern Australia and the Cocos-Keeling Islands).

Habitat. Coral reef amongst rubble; 8.9–55 m.

Distribution. Western Pacific to eastern Indian Ocean, from southern Japan to Papua New Guinea, the Solomon Islands, New Caledonia and northern Australia.