Gonodactylopsis drepanophora ( de Man, 1902 )

Ahyong, Shane T., 2022, Revision of the Indo-West Pacific Coral Reef Mantis Shrimp Genus, Gonodactylopsis Manning, 1969 (Crustacea: Stomatopoda: Gonodactylidae), Records of the Australian Museum 74 (2), pp. 41-57 : 45-48

Gonodactylopsis drepanophora ( de Man, 1902)

Figs 1, 3, 4

Gonodactylus drepanophorus de Man, 1902: 914–919 , pl. 27 fig. 68.— Borradaile, 1907: 210.— Kemp, 1913: 4, 11, 146, 148, 173, 174.— Hansen, 1926: 30–31, pl. 2 fig. 1a.

Mesacturus drepanophorus .— Manning, 1967: 2.— Manning & Serène, 1968: 114.— Shanbhogue, 1975: 524, 539.

Gonodactylopsis drepanophora .— Manning, 1969: 150.— Moosa, 1974: 73–76, fig. 1.— Chhapgar & Sane, 1977: 32.— Manning, 1995: 20.— Wang & Liu, 1998: 141, tab. 2.— Erdmann & Manning, 1998: 621.— Barber et al., 2012: tab. 1.— Huffard et al., 2012: tab. 1.— Padate et al., 2021: 558–561 , figs 1A, 2, 3.

Gonodactylopsis drepanophorus .— Schram & Müller, 2004: 44.

Type material. Holotype: SMF 5773 , female (TL 19 mm), Ternate, Indonesia, coll. W. Kükenthal, 1894.

Other material examined. Indonesia: USNM 155707 , 1 female (TL 18 mm), Ambon , 13–20 m, coll. Kurnaen, 24 February 1973 ; MZB LIPI S.562, 1 female (TL 14 mm), Ambon Bay , 80 m, mud and rubble , RV Samudera , 26 September 1970 . Japan: USNM 307225 , 1 female (TL 22 mm), Horseshoe Cliffs , 1 km WNW of Onna Village, Okinawa, 26°30'N 127°50.88'E, 58 m, on scuba, RFB 0872, coll . R.F. Bolland , 4 July 1981 . Australia: WAM C54190 ,

1 female (TL 20 mm), S end Ashmore Reef, 12°17.76'S 123°01.632'E, 12 m, Woodside Kimberley Survey 2013 stn 134/K13, coll. L. Avery, 30 September 2013; WAM C54164 , 1 female (TL 20 mm), SW Ashmore Reef, 12°16.488'S 122°58.878'E, 12 m, Woodside Kimberley Survey 2013 stn 133/K13- T1 , coll. A. Hosie, 30 September 2013; WAM C61240 , 1 female (TL 16 mm), E Ashmore Reef, 12°11.574'S 123°07.734'E, intertidal, Woodside Kimberley Survey 2013 stn 131/K13- T2 , coll. A. Hosie, 29 September 2013; WAM C54274 , 1 male (TL 12 mm), E Ashmore Reef, 12°12.468'S 123°08.736'E, 12 m, Woodside Kimberley Survey 2013 stn 140/K13- T1 , coll. A. Hosie, 3 October 2013.

Description. Eyes elongate; cornea subconical, reaching anteriorly almost to end of antennular article 3. Ocular scales low, rounded.

Antennular peduncle length 0.5–0.7CL. Antennal protopod with fixed, laterally flattened mesiodorsal spine, short anteroventral tooth; antennal scale length 0.3–0.4CL.

Rostral plate slightly wider than long; median spine about twice length of basal portion (medially), laterally compressed, with obtusely angular ventral keel; lateral spines divergent with arcuate margins.

Raptorial claw dactylus with proximal notch on outer margin; propodus with proximal movable spine, opposable margin sparsely pectinate proximally.

Mandibular palp 2- or 3-segmented. Maxillipeds 1–5 each with epipod.

Thoracic somites 6 and 7 lateral processes subequal, lower margins subtruncate. Thoracic somite 8 anterolateral margin rounded; sternal keel obsolete.

Pleopod 1 endopod with lateral lobe on posterior “endite”.

Abdominal somites 1–5 posterolateral angles unarmed. AWCLI 671–822. Abdominal somite 6 with submedian, intermediate and lateral bosses posteriorly armed.

Telson wider than long; 10–14 submedian denticles arising from inner margin of submedian teeth; 2 intermediate and 1 lateral denticles usually distinct; submedian and intermediate teeth slender, sharp; submedian teeth subparallel to slightly divergent; intermediate teeth length at least twice width, extending posteriorly to slightly beyond midlength of submedian teeth; lateral teeth stout, triangular, apex acute, directed posteriorly. Median carina inflated, more so in males than females, with posterior spine; accessory median with 2 (rarely 3) spines; anterior submedian carina composed of 2–4 spines in longitudinal row or cluster; submedian tooth with anterior cluster and irregular row of 1–7 dorsal spines (number increasing with body size), not extending beyond anterior half; anterior intermediate carina composed of 2–4 spines; intermediate tooth with 1–4 dorsal spines; knob absent; submedian and intermediate teeth with distinct ventral carina.

Uropodal protopod terminal spines with outer slightly longer than inner, each with ventral carina, inner with dorsal carina; upper proximal surface with obtuse swelling behind dorsal carina in specimens> TL 14 mm; slender spine above exopod articulation. Exopod proximal article dorsal surface with sharp, straight longitudinal carina and two short subequal carinae mesial to main carina; outer margin with 10–12 movable spines, distalmost reaching distal one-third of distal article; inner margin smooth, glabrous; distal margin with small ventral spine. Exopod distal article with outer distal margin setose, inner margin glabrous; dorsal and ventral surfaces with inner quarter to half membranous, soft, wrinkled, clearly demarcated from chitinized outer portion; outer chitinized portion with prominent, curved carina dorsally, ventrally smooth. Endopod length 2.1–3.1× width, crescentic, articulation with protopod posterior to anterior end; outer margin strongly convex, setose along distal half, inner margin strongly, irregularly concave, glabrous; dorsally with sharp, curved carina adjacent to outer margin; dorsal and ventral surfaces with inner half membranous, soft, wrinkled, clearly demarcated from chitinized outer half.

Colouration in preservative. Largely faded to pale yellowbrown. Carapace with scattered chromatophores, mottling and pair of small spots across cervical region. Thoracic somite 6 and abdominal somite 1 with rectangular field of small irregular chromatophores and larger median black spot. Abdominal somites 2–5 with transverse row of 2 or 3 small rounded spots.

Measurements. Male (n = 1) TL 12 mm; female (n = 7) TL 14–22 mm. Other measurements of holotype: CL 4.1 mm, antennular peduncle length 2.2 mm, antennal scale length 1.3 mm, abdominal somite 5 width 2.8 mm.

Remarks. Gonodactylopsis drepanophora is distinguished by the combination of a crescentic uropodal endopod and a telson having slender, pointed primary teeth and a multispinose dorsal surface. Of the known species of the genus, G. drepanophora most closely resembles G. maqqaba from the South China Sea, differing chiefly in the crescentic rather than linear uropodal endopod; other distinguishing features are discussed under the account of the latter. Gonodactylopsis drepanophora was described from Ternate, Indonesia, and subsequently recorded from Timor Leste ( Hansen, 1926), Ambon, Indonesia ( Moosa, 1974) and the Andaman Sea ( Padate et al., 2021). The present records of G. drepanophora from Japan and northwestern Australia are the first for these localities.

The specimens of G. drepanophora accord well, particularly those from Japan, Indonesia, and northwestern Australia. The holotype, however, exhibits an abnormality in the absence of the left lateral primary tooth of the telson ( Fig. 3E ), possibly the result of injury during moulting. The record from the Andaman Sea represents the largest known specimen of the species (TL 24 mm; Padate et al., 2021: figs 1A, 2, 3), and differs subtly from the smaller specimens in having a 2- rather than 3-articled mandibular palp, slightly more divergent submedian telson teeth, and a cluster of 3 or 4 spines, rather than a single spine, at the base of the intermediate telson teeth. These differences, for which the significance is not clear, are presently regarded as intraspecific variation.

Allometric variation in G. drepanophora follows a similar trajectory to that observed for G. lata in the increasing slenderness and elongation of the primary telson teeth, increasing density of dorsal telson spination, and more pronounced curvature of the uropodal endopod with increasing body size ( Hansen, 1926: pl. 2 fig. 1a; Figs 3E,H , 4F,K ). The dorsal tubercle on the uropodal protopod is present in all except the smallest specimen (juvenile male, TL 12 mm, WAM C54274; Fig. 3I ).As with G. lata , the lateral lobe on the posterior “endite” of pleopod 1 in the juvenile male is yet to be fully developed ( Fig. 3J ). Notably, the proportionally shorter primary telson teeth of the juvenile male of G. drepanophora ( Fig. 3I ) closely resemble those of adults of members of the G. molyneux group, such as G. barberi Ahyong & Erdmann, 2007 and G. snidvongsi (Naiyanetr, 1987) ( Ahyong & Erdmann, 2007: fig. 4; Ahyong, 2008: fig. 2), suggesting these and allied species could be paedomorphic.

Distribution. Western Pacific to eastern Indian Ocean, from Japan to Timor Leste, Indonesia, Ashmore Reef and the Andaman Islands; 13– 80 m.

Figures

Figure 3. Gonodactylopsis drepanophora (De Man, 1902): A–H, holotype female, TL 19 mm, Ternate, Indonesia, SMF 5773; I–J, male, TL 12 mm, E Ashmore Reef, WAM C54274. (A) anterior cephalothorax, dorsal view; (B) ocular scales; (C) right antenna, lateral view; (D) right raptorial claw, lateral view; (E, I) abdominal somite 6, telson and right uropod; (F) telson, lateral view; (G) telson submedian and intermediate teeth, ventral view; (H) right uropod, ventral view; (J) right pleopod 1 endopod, anterior view. Scale: A–H = 1.0 mm, I = 0.8 mm, J = 0.4 mm.

Figure 4. Gonodactylopsis drepanophora (De Man, 1902): A–J, female, TL 22 mm, Okinawa, Japan, USNM 307225; K, female, TL 18 mm, Ambon, Indonesia, USNM 155707. (A) anterior cephalothorax, dorsal view; (B) ocular scales; (C) right antenna, lateral view; (D) right raptorial claw, lateral view; (E) thoracic somites 6–8, lower right lateral view; (F) abdominal somite 6, telson and right uropod; (G) abdominal somites 4 and 5 posterolateral margin, lateral view; (H) right uropod, ventral view; (I) telson, right lateral view; (J) telson, ventral view; (K) telson, dorsal view. Scale = 1.0 mm.