Gonodactylellus celosinus, Ahyong, 2024

Ahyong, Shane T., 2024, A new coral reef mantis shrimp from the northwestern Indian Ocean, Gonodactylellus celosinus sp. nov. (Crustacea: Stomatopoda: Gonodactylidae), Zootaxa 5481 (4), pp. 453-462 : 454-460

Gonodactylellus celosinus sp. nov.

( Fig. 1 , 2 )

Gonodactylus demani. — Kemp 1913: 164, figs. 108, 110 [part, Red Sea and Persian Gulf specimens].— Tattersall 1921: 359– 360.— Kemp & Chopra 1921: 297, 309–310 [part, Red Sea and Persian Gulf specimens].— Ramadan 1936: 8.— Makarov 1971: 154.— Basson et al. 1977: 47, 73, 227, 234, 237.— Hughes 1977: 90.

Gonodactylus Demani. — Nobili 1905: 11.— Parisi 1940: 4, 6.

Gonodactylus De Mani. — Nobili 1906a: 330.— Maccagno 1936: 179.— Dollfus 1938: 213 [part, Red Sea and Persian Gulf only].

Gonodactylus de Mani. — Nobili 1906b: 158.

Gonodactylus demanii .—Holthuis 1941: 282, fig. 8a [part, Red Sea specimens only].— Stella 1955: 69.— Dollfus 1959: 242 [part; discussion].— Holthuis 1967: 32–34, 41.— Manning 1967: 8–10, fig. 3 [part, except Gulf of Mannar specimen].— Shanbhogue 1969: 35 [part, Gulf of Kutch record only].— Fishelson 1971: 119, 128.— Manning & Lewinsohn 1986: 6, 7, 15, 16.— Shanbhogue 1986: 519, 521 [part, Gulf of Kutch record only].— Manning 1989: tab. 1.— Manning 1990: 98, 104.— Tirmizi et al. 1994: 161, fig. 35.— Joydas & Borja 2019: 234, 239.

Gonodactylus demani demani .— Ingle 1963: 27 [part, Red Sea records only].

Gonodactylus hendersoni Manning, 1967: 4 [part, holotype only; paratypes represent other species].

Gonodactylus demani var. spinosus ?— Kemp & Chopra 1921: 311 [Pearl Banks, Persian Gulf; not G. spinosus Bigelow, 1893 ].

Gonodactylellus demanii .— Trivedi et al. 2020: 224 [part, Gujarat and Maharashtra records only].— Vadher et al. 2022: 21034 – 21036, image 1, tab. 1, 2.

Type material. Holotype: SMF 62255 , male (TL 27 mm), Alkhuraybah , Red Sea, 28°00’50.40”N, 35°09’47.10”E, 0.5 m, sandy-bottom & coral rocks, RSS1-2013 - 35 , coll. A. Brösing, A. Alhaj & B. Werding, 26 June 2013 . Paratypes: SMF 62256 , 1 male (TL 36 mm), 2 females (TL 20–24 mm), Alkhuraybah , Red Sea, 28°00’50.40”N, 35°09’47.10”E, 0.5 m, sandy-bottom & coral rocks , RSS1-2013 - 35 , coll. A. Brösing, A. Alhaj & B. Werding, 26 June 2013 ; KAUMM 1059 , 1 male (TL 27 mm), 3 females (23–50 mm), same ( RSS1-2013 - 35 ) .

Other material examined. RED SEA: SMF 62257 , 1 female (TL 17 mm), Al Wajh , Red Sea, 26°03’29.80”N, 36°35’41.00”E, intertidal reef flat, dead corals, RSS1-2013 - 1 , coll. A.A.J. Kumar, 11 June 2013 ; KAUMM 1060 , 1 male (TL 31 mm), 4 juvenile males (TL 12–15 mm), 4 females (TL 23–31 mm), 1 juvenile female (TL 11 mm), Alkhuraybah , Red Sea, 28°06’27.60”N, 34°59’27.20”E, 0.5 m, sandy bottom with coral rocks, digging, RSS1-2013 - 37 , coll. A. Alhaj, 23 June 2013 ; KAUMM 1061 , juvenile male (TL 13 mm), Al Lith , 20°12.012’N, 40°07.104’E, RSS1-2012 - 58 , reeftop, coral rubble, 6 March 2012 ; SMF 62258 , 3 males (TL 19–27 mm), 5 females (TL 16–36 mm), Zufaf Island, Farasan Islands , 16°44.092’N, 41°44.679’E, 0.5–1.0 m, under stones, RSS1-2012 - 36 , coll. A. Brösing, 26 February 2012 ; SMF 62259 , 2 females (TL 22–24 mm), north of Jeddah , RSS1-2011 , coll. A. Brösing, 26 April 2011 ; KAUMM 1062 , 1 male (TL 29 mm), Farasan Islands , 16°45.315’N, 42°03.694’E, low tide in front of mangroves, hand dredge, RSS1-2012 - 27 , coll. A. Brösing, 24 February 2012 ; KAUMM 1063 , 1 female (TL 20 mm), Sasu Island, Farasan Islands , 16°52.211’N, 41°35.545’E, 0.5–2.0 m, bench with coral heads, RSS1-2012 - 18 , coll. A. Brösing, 21 February 2012 ; SMF 62260 , 1 male (TL 23 mm), Farasan Islands , 16°43.130’N, 42°03.902’E, 0.5–1.0 m, beach with dead corals, RSS1-2012 - 10 (2), coll. A. Brösing, 23 February 2012 ; SMF 62261 , 1 juvenile male (TL 12 mm), Al Lith , 20°16.003’N, 39°59.443’E, beach, RSS1-2011 - 01 , coll. A. Brösing, 29 March 2011 ; KAUMM 1064 , 1 male (TL 20 mm), Khotib Harbour, Farasan Islands , 16°54.912’N, 41°50.578’E, RSS 1-2012- 14, 21 February 2012 ; SMF 62262 , 3 females (TL 19–30 mm), Aboshok Island, Farasan Islands , 16°59.160’N, 41°47.456’E, 0.8–0.9 m, limestone bench with brown algae, RSS1-2012 - 38 , coll. A. Brösing & V. Spiridonov, 27 February 2012 ; SMF 62263 , 1 male ( TL 19 mm), Al Lith , 20°15.922’, 39°59.496’E, 0.5 m, beach, hand dredge, RSS1-2012 - 49 , coll. A. Brösing, 4 March 2012 ; KAUMM 1065 , 1 female (TL 20 mm), Al Lith , 20°15.231’N, 39°59.352’E, 0.2–0.4 m, hand dredge and hand net in debris of seagrass and algae, reef flat, RSS1-2012 - 53 , coll. A. Grishchenko, 6 March 2012 ; KAUMM 1066 , 1 female (TL 24 mm), Jeddah , RSS1-2011 , coll. A. Brösing, 17 April 2011 ; SMF 62264 , 1 female (TL 11 mm), Al Lith , 20°14.192’N, 40°03.741’E, mangroves, algae & seagrass, RSS1-2012 - 57 , coll. A. Brösing, S. Tränkner, V. Spiridonov & A. Mal, 6 March 2012 .

GULF OF ADEN: FLMNH UF32746 , 1 female (TL 26 mm), Djibouti, in front of Sheraton Hotel , 11.6012°N, 43.159°E, 0–2 m, fringing sand flat with some scuzz, BDJRS-0018, DJRS-001, coll. G. Paulay, 26 September 2012 .

PAKISTAN: USNM 120473 , 1 female (TL 22 mm), western end Astola Island , ca. 177 miles west of Karachi, 0–2.4 m, rocks, sand, scattered coral, International Indian Ocean Expedition Sta. LW-l, coll. L.P. Woods et al., 27 November 1963 .

Diagnosis. Ocular scales rounded, separate. Rostral plate basal portion with straight anterior margins, transverse to sloping posteriorly; anterolateral angles rounded. Raptorial claw dactylus with shallow notch on outer proximal margin. Mandibular palp 3-segmented. Telson intermediate teeth distinct, apices sharp, extending posteriorly well beyond apices of intermediate denticles; lateral teeth projecting well off margin of telson by wide notch (in specimens> TL 19–20 mm). Telson median and accessory median carinae together with group of usually 5 or 6 posterior spines; anterior submedian carina with 1–3 (usually 2) spines; submedian tooth with proximal cluster of 1–3 (usually 2 or 3) spines proximally; intermediate tooth with 1 dorsal spine preceded by 1–3 (usually 2) spines on anterior intermediate carina; ventral surface of submedian and intermediate teeth flat, without longitudinal carina along midline. Uropodal protopod with low obtuse swelling behind dorsal carina. Uropodal exopod proximal article inner margin smooth, glabrous; distal margin with ventral spine; exopod distal article with outer margin setose, inner margin smooth, glabrous. Uropodal endopod about 3 times as long as wide; distal half of outer margin setose, inner margin smooth, glabrous except for 3–11 (usually 4 or 5) proximal setae.

Description. Eyes elongate; cornea subconical. Ocular scales rounded, separate, bases transverse. Antennular peduncle length 0.61–0.83CL. Antennal scale length 0.45–0.50CL.

Rostral plate longer than wide; basal portion with straight anterior margins, transverse to sloping posteriorly; anterolateral angles rounded; lateral margins divergent anteriorly; median spine longer than base, laterally compressed, with obtusely angular ventral keel.

Raptorial claw dactylus with shallow notch on outer proximal margin. Propodus proximal movable spine slender; opposable margin sparsely pectinate proximally. Carpus dorsal margin unarmed.

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

Thoracic somite 6 lateral process subequal to that of thoracic somite 7; lower margins subtruncate. TS8 anterolateral margin rounded; sternal keel obsolete.

Pereopods 1–3 endopod slender, linear, 2-segmented; proximal article unarmed.

Male pleopod 1 endopod with well-developed lateral lobe on posterior endite.

Abdominal somites 1–5 posterolateral angles unarmed. AWCLI 792–875. Abdominal somite 6 with posterior spine of submedian, intermediate and lateral carinae distinct in juveniles and females, often obscure or obsolete in adult males.

Telson wider than long; with 7–12 (usually 8 or 9) spiniform submedian denticles; intermediate teeth distinct, apices sharp, extending posteriorly well beyond apices of intermediate denticles; lateral teeth demarcated by wide notch in specimens> TL 19–20 mm), apex angular, projecting well off margin of telson. Telson median carina ovate, usually obscuring accessory median carina, together with a group of usually 5 or 6 posterior spines (1–3 [usually 1 or 2] spines on median, 0–3 [usually 2] spines on each accessory median); anterior submedian carina with 1–3 (usually 2) spines in longitudinal row; submedian tooth with proximal cluster of 1–3 (usually 2 or 3) spines proximally; intermediate tooth with 1 dorsal spine preceded by 1–3 (usually 2) spines on anterior intermediate carina; knob absent; ventral surface flat, without longitudinal carina along midline of submedian and intermediate teeth.

Uropodal protopod terminal spines with outer slightly longer than inner; upper proximal surface with low obtuse swelling behind dorsal carina. Uropodal exopod proximal segment outer margin with 9–15 (usually 11) movable spines, distalmost slightly exceeding apex of distal segment; inner margin smooth, glabrous; distal margin with ventral spine; exopod distal segment with outer margin setose, inner margin smooth, glabrous. Uropodal endopod length 2.81–3.16 times width; distal half of outer margin setose, inner margin smooth, glabrous except for 3–11 (usually 4 or 5) proximal setae.

Etymology. The specific epithet is derived from the Latin, celo (hide, conceal), and sinus (bay, gulf), in recognition that the new species has been “hiding in plain sight” in the bays and gulfs of the Arabian Sea for more than a century; used as a noun in apposition.

Measurements. Male (n = 17) TL 12–36 mm, female (n= 27) TL 11–36 mm. Other measurements of the holotype: CL 5.44 mm, antennular peduncle length 3.59 mm, antennal scale length 2.69 mm, abdominal somite 5 width 4.50 mm. Holthuis (1967) recorded specimens from the Red Sea to TL 40 mm (as G. demanii ).

Remarks. Gonodactylellus celosinus sp. nov. has long been mistaken for G. demanii , probably because the latter species has never been adequately characterized or figured. To facilitate recognition of G. demanii sensu stricto, figures are provided of material from the Gulf of Mannar ( Fig. 3 ). Within the molyneux group, G. celosinus sp. nov. most closely resembles G. demanii (type locality: Rameswaram, Gulf of Mannar, India) and G. oshea Ahyong, 2012 (type locality: New Zealand) in sharing the combination of a slender uropodal endopod (length about 3× width) with several proximal setae on an otherwise glabrous inner margin, and with the ventral surface of the submedian primary teeth of the telson either non-carinate ( G. celosinus sp. nov., G. oshea ) or unicarinate ( G. demanii ), rather than bicarinate ( G. bicarinatus ). Gonodactylellus celosinus sp. nov. differs from G. demanii sensu stricto in features of the rostral plate with the anterior margin sloping posteriorly to almost transverse with rounded anterolateral corners ( Figs. 1A , 2 ) (versus anterior margin concave and inclined anteriorly with acute anterolateral corners; Fig. 3A ), ocular scales distinctly separate rather than medially fused and separated only by shallow concavity ( Figs. 1A, C , 2 , 3A, C, M ), presence of a notch on the outer proximal margin of the dactylus of the raptorial claw ( Fig. 1E ) (absent in G. demanii ; Fig. 3E ), and absence of a carina along the ventral midline of each submedian telson tooth (present in G. demanii ; Fig. 3L ). Whereas the ventral surface of each submedian telson tooth carries a prominent longitudinal carina along the midline in G. demanii , the ventral surface of the submedian teeth in G. celosinus sp. nov. is essentially smooth and flat, with the mesial margin forming a blunt, narrow step adjacent to the submedian denticles ( Fig. 1K ). Note that Manning (1967) diagnosed G. demanii as lacking the prominent ventral carina of the submedian telson teeth (at most a low mesial ridge), but re-examination of the type material and other Indian material showed the carinae to be present. Although G. celosinus sp. nov. has long been mistaken for G. demanii , the new species is morphologically nearest to G. oshea from the southwestern Pacific ( New Zealand) in sharing similar rostral plate form and ventral telson ornamentation. Gonodactylellus celosinus sp. nov. differs from G. oshea in having rounded ocular scales (versus truncate in G. oshea ), and, in specimens exceeding TL 19–20 mm, the orientation of the lateral primary teeth of the telson. In G. oshea , the lateral primary teeth are sharply acute and set-off from the margin of the intermediate tooth by a narrow notch ( Ahyong 2012: fig. 9B). In G. celosinus sp. nov., however, the apex of the lateral tooth is angular but not spiniform and set-off from the margin of the intermediate tooth by a wide notch ( Figs. 1H, K , 2A, B ). Note that the prominence of the lateral primary tooth varies allometrically in G. celosinus sp. nov. ( Fig. 2C, D ). In specimens of G. celosinus sp. nov. below about TL 19–20 mm, the lateral primary tooth may approach that of G. oshea , so in smaller specimens, the shape of the ocular scales should be used to distinguish the species.

Sexual dimorphism in G. celosinus sp. nov. is evident in the more inflated dorsal telson carinae in males, as is typical of other gonodactylids.As in other members of the molyneux group ( Ahyong & Erdmann 2007; Ahyong 2008), the degree of dorsal spination of the telson (but also bluntness of the spines), progressively increases with increasing body size ( Figs. 1H, I , 2 ). In females and smaller males, the apices of the dorsal telson spines are typically pointed, but in males above about TL 25–27 mm, the pointed apices may become obsolete and blunt as figured by Kemp (1913: pl. 9 fig. 109; as G. demanii ). Similarly, the apices of the submedian and intermediate carina of abdominal somite 6 become smaller or even obsolete with increasing body size. As in other stomatopods, the relative length of the antennular peduncle decreases with increasing size, being about 0.8CL in the smallest specimens to about 0.6–0.7CL in adults. The mandibular palp is present in all specimens examined, but is unsegmented in the smallest specimen (juvenile female, TL 11 mm). At TL 12–13 mm, the second article of the mandibular palp is differentiated, and by TL 14 mm, the third palp article is differentiated. The dorsal swelling on the uropodal protopod is low but evident by TL 15 mm. In males, the modified pleopod 1 endopod is fully developed by TL 19 mm.

Gonodactylellus celosinus sp. nov. apparently occurs only in the northwestern Indian Ocean, from Somalia, the Red Sea, the Persian Gulf and the Arabian Sea. The previous record of G. demanii from Astola Island, Pakistan ( Manning 1967; Tirmizi & Manning 1968) is referable to G. celosinus sp. nov. ( Fig. 2B ) The only previous records of G. demanii from western India are from the far north: Mumbai (as Bombay) and the Gulf of Kachchh ( Kemp 1913; Shanbhogue, 1969; Trivedi et al., 2020; Vadher et al., 2022). The Gulf of Kachchh records are referable to G. celosinus sp. nov., as clearly depicted by Vadher et al. (2022: image 1a–f). The record from Mumbai ( Kemp, 1913) requires confirmation but is probably also referable to G. celosinus sp. nov. Gonodactylellus demanii sensu stricto is reliably now known only from the Bay of Bengal between southeastern India (Gulf of Mannar) and Burma.

Habitat. Intertidal and shallow subtidal reefs to 3 m depth ( Holthuis 1967); amongst rubble and in crevices in coral sponge and algae.

Colour in preservative. Largely faded, with scattered chromatophores on carapace, thorax, abdomen and raptorial claw; with rectangular median patch of chromatophores on thoracic somite 6 and abdominal somite 1, and small median cluster on abdominal somites 3–5; abdominal somite 6 and telson with diffuse olive green mottling.

Distribution. Northwestern Indian Ocean: Somalia, the Red Sea, Persian Gulf and Arabian Sea including Pakistan and northwestern India.

Figures

FIGURE 1. Gonodactylellus celosinus sp. nov., male holotype, TL 27 mm, Red Sea, SMF 62255; A, anterior cephalothorax; B, rostral plate, right lateral view; C, ocular scales, dorsal view; D, right antennal protopod, lateral view; E, right raptorial claw, lateral view; F, thoracic somites 6–8, right lateral view; G, abdominal somites 4–5 posterolateral angles, right lateral view; H, abdominal somites 5–6, telson and right uropod, dorsal view (setae omitted); I, abdominal somite 6 and telson, lateral view; J, right uropod, ventral view; K, telson, ventral surface; L, right pleopod 1 endopod, anterior view. Scale: A–K = 2.0 mm, L = 1.0 mm.

FIGURE 2. Gonodactylellus celosinus sp. nov., telson, ocular scales and rostral plate, dorsal view: A, female paratype, TL 24 mm, Red Sea, RSS1-2013-35, SMF 62256; B, female, TL 21 mm, Astola Island, Pakistan, USNM 120473; C, juvenile female, TL 11 mm, Red Sea, RSS1-2013-37, KAUMM 1060; D, juvenile male, TL 14 mm, Red Sea, RSS1-2013-37, KAUMM 1060. Scale: A, B = 2.0 mm; C, D = 1.0 mm.

FIGURE 3. Gonodactylellus demanii (Henderson, 1893), Kilakarai, Gulf of Mannar, India, AM P3967: A–L, female, TL 26 mm; M–N, female, TL 18 mm. A, anterior cephalothorax; B, rostral plate, right lateral view; C, M, ocular scales, dorsal view; D, right antennal protopod, lateral view; E, right raptorial claw, lateral view; F, thoracic somites 6–8, right lateral view; G, abdominal somites 4–5 posterolateral angles, right lateral view; H, abdominal somite 6, telson and right uropod, dorsal view (setae omitted); I, abdominal somite 6 and telson, lateral view; J, right uropod, ventral view; K, left uropodal endopod, dorsal view (setae omitted); L, telson, ventral surface; N, rostral plate, dorsal view. Scale = 2.0 mm.