Rayllianassa amboinensis (De Man, 1888 )

Poore, Gary C. B., 2023, New records, one new genus and 21 new species of Callianassidae (Crustacea, Axiidea) from the Indo-West Pacific, Memoirs of Museum Victoria 82, pp. 167-255 : 223-224

Rayllianassa amboinensis (De Man, 1888)

Figures 1f , 38 , 39

Callianassa amboinensis De Man, 1888: 480 , pl. 20 fig. 4.— Zehntner, 1894: 194.–– Poore and Griffin, 1979: 248, fig. 14.— Sakai, 1984: 96–99, figs 1, 2.— Sakai, 1988: 53, 57, fig. 1.— Ngoc-Ho, 1991: 283, fig. 1.— Sakai, 1999: 35, 38.— Tudge et al., 2000: 143.— Ngoc-Ho, 2005: 68, fig. 12.

Callianassa (Calliactites) amboinensis .—Borradaile, 1903: 545.

Callianassa (Trypaea) amboinensis .—De Man, 1928a: 27, 93, 107, 165, pl. 18 fig. 28.

Callianassa ngochoae Sakai, 1999: 36 , 49.—Komai et al., 2014: 553–554 (synonymy with C. amboinensis ). – Poore et al., 2019: 98, 139, 146 (genus incertae sedis). Callianassa sahul Poore, 2008: 172–174 , fig. 5. Syn. nov.

Callianassa sp. MoV 4964.— Poore et al., 2008: 92.

Notiax amboinensis .— Sakai, 2011: 382.

Notiax ngochoae .— Sakai, 2011: 384–385.

Rayllianassa amboinensis .—Komai and Tachikawa, 2008: 43–47, figs 13–15 (Ogasawara Is).—Komai et al., 2014a: 551–554, figs 1, 2.— Poore et al., 2019: 136, 143.

Rayllianassa cf. amboinensis .— Robles et al., 2020: figs 1, 3, 6 (part).

Trypaea sahul .— Sakai, 2011: 407–408.

Rayllianassa sahul .— Poore et al., 2019: 140, 143.

Material examined. Mariana Islands. Guam I., Hospital Point, 13.502084° N, 144.768206° W, 93–95 m, UF 13834 (female, 2.4 mm). Palmyra Atoll, N side, 5.8978° N, 162.0628° E, 0–13 m, UF 11709 (ovigerous female, 3.0 mm). Line Islands , Kingman Reef, NEE of Atoll, 6.4036° N, 162.3427° E, UF 11678 * (ovigerous female, 4.2 mm) . Philippines. 12° 31' N, 120° 39' E, 92–97 m, in sponge (stn MUSORSTOM 3 117), MNHN Th-1227 (female, 4 mm) . Papua New Guinea. Bismarck Archipelago, N side of Rara I., Seeadler Harbour, Off Lorengau Town, 2° S, 147.27° E, 3–17 m, associated with Porifera, UF 8700 * (ovigerous female, 4.3 mm). Salomon Sea. N of Normanby I., d’Entrecasteaux Archipelago , 09° 49' S, 151° 34' E, 150–180 m ( MADEEP stn DW4316 ), MNHN IU-2014-18537 (female, 3.3 mm). Madang Province, 05° 11' S, 145° 48.4' E, 8 m, in dead corals ( PAPUA NIUGINI stn PB11 ), MNHN IU-2013-7058 * (female, 4.0 mm); MNHN IU-2013-325 (ovigerous female, 6.5 mm); 05° 10.8' S, 145° 49.8' E, 22 m (PAPUANIUGINIstnPR10),MNHNIU-2013-7049*#(ovigerous female, 4.1 mm); 05° 15.9' S, 145° 47.1' E, 10 m ( PAPUA NIUGINI stn PB37 ), MNHN IU-2013-7079 *# (ovigerous female, 5.2 mm). Kavieng Province , 02° 32' S, 150° 47' E, 130–144 m (KAVIENG 2014 stn DW 4499 ), MNHN IU-2015-989 (female, 4.4 mm) . New Caledonia. MNHN Th-1071 (holotype of Callianassa ngochoae , male/immature, 2.8 mm) . Australia. Arafura Sea (Geosciences Australia stn 2012t 07/183), NMV J71761 (ovigerous female, 9.3 mm). Timor Sea , Sahul Banks , W of Mangol Shoal, 11° 40.26' S, 125° 04.84' E, 18 m, NMV J53340 (holotype of Callianassa sahul , ovigerous female, cl. 4.3 mm). WA, 5.4 km E of Tish Point, Rosemary I., Dampier Archipelago , 20.498° S, 116.64° E (stn DA2/84/1), NMV J53341 (2 females, 4.2, 7.8 mm). WA, off Point Cloates , 22° 50.55' S, 113° 30.40' E, 100 m, NMV J53457 (ovigerous female) .

Diagnosis. Antennular peduncle longer than antennal peduncle. Major cheliped merus lower margin straight or convex, smooth or with small teeth; carpus oval in cross-section, upper and lower margins weakly carinate; palm upper margin weakly carinate, without tubercles and ridges on distal mesial and lateral margins at the base of fingers; dactylus straight or strongly curved, with blade along cutting edge or with basal tooth, apex simple. Pereopod 3 propodus suboval-angular, lower margin with distinct corner between straight proximal half and concave distal half. Uropodal exopod widest near midpoint, about as long as wide.

Distribution. Central and Eastern Indo-Pacific ( Japan, Philippines, New Caledonia, Marquesas Is., Easter I., Indonesia [type locality: Ambon], Papua New Guinea, northern Australia); 0–183 m, associated with sponges and alcyonaceans (Komai et al., 2014b).

Remarks. As Komai and Tachikawa (2008), who described the species in detail, and Komai et al. (2014a) noted, R. amboinensis has been reported from throughout the Indo-West Pacific and illustrated several times since its discovery in Ambon, Indonesia (De Man, 1928a; Poore and Griffin, 1979; Sakai, 1984, 1988; Ngoc-Ho, 2005; Komai and Tachikawa, 2008; Komai et al., 2014a). There are some discrepancies between the illustrations, indicating that more than one species may be involved, but the three new species described below and revealed by Robles et al.’s (2020) molecular analysis have not been illustrated previously.

Rayllianassa amboinensis is recognised by the almost circular maxilliped 3 ischium+merus, the antennal peduncle reaching near or just beyond the midpoint of article 3 of the antennular peduncle, the triangular anterodistal lobe of the eyestalk, the palm of the major cheliped lacking a carina on the upper margin and lacking teeth on its distal margins, and the asymmetry of the lower margin of the propodus of pereopod 3 (more convex proximally than distally). Komai et al. (2014b) noted that the cervical groove is incised and a dorsal oval (postrostral depression) is present (figs 39d, 40j). The genetic variability between the four individuals from Papua New Guinea and one from the Line Islands (those remaining in R. amboinensis after the three new species are removed) is reflected in some morphological variability (figs 39, 40). The rostrum is more prominent in some individuals than others, the telson ranges from as long as wide to longer than wide, the length:width ratio of the uropodal rami ranges widely, the merus of the major cheliped has no or few small teeth along its lower margin and is wider in some than others, the minor palm ranges from 0.6 to 0.75 times as wide as the major palm. Ovigerous females range from cl. 3.3 mm to cl. 9.3 mm, a considerable range that may explain some of the morphological variation. For the time being it is concluded that this material represents only one species consistent with the illustrations of De Man (1928a: Ambon), Poore and Griffin (1979: NW Australia), Sakai (1988: NT, Australia), Ngoc-Ho (1991: New Caledonia), Komai and Tachikawa (2008: S Japan) and Komai et al. (2014b: S Japan). In other illustrations, Sakai (1984: N Australia) and Ngoc-Ho (2005: Marquesas), the major cheliped palm is more barrel-shaped than typical, suggesting that R. amboinensis represents a species complex as yet unresolved.

All authors cited above have reported only females, but all individuals (except one) checked here are in fact hermaphrodites with both male and female gonopores. Sakai (1999) noted that in the individual from New Caledonia identified as C. amboinensis by Ngoc-Ho (1991), the antennal peduncle article 5, the merus of the major cheliped and the telson differed from those of C. amboinensis and erected a new species, C. ngochoae Sakai, 1999 . Later, Sakai (2005) returned C. ngochoae to synonymy with C. amboinensis . Later still, Sakai (2011) revived his 1999 species as what he then called “ Notiax ngochoae ”, including in its synonymy several citations of C. amboinensis , including De Man’s (1928a) description of its holotype. Komai et al. (2014b) summarised the complicated arguments for and against the synonymy of the two species. None of these arguments noted that the antennular peduncle scarcely exceeds the antennal peduncle (shorter than is typical) ( Ngoc-Ho, 1991: fig. 1a, b) but its length relative to the carapace is similar to that in other individuals. The holotype is very small (cl. 2.8 mm) with a minute pleopod 1 and two-articled pleopod 2 (confirmed by re-examination). Ngoc-Ho (1991) assumed it to be a male but it may be immature, which could explain the unusual relative size of the antennae. The maxilliped 3, eyestalks, rostrum and relative size of the chelipeds are consistent with the specimen belonging to R. amboinensis .

Re-examination of the holotype of C. sahul Poore, 2008 has shown that it does not differ substantially from R. amboinensis (fig. 38a–c), and it is here synonymised.

As Komai et al. (2014b) argued, and elaborated above under Remarks for Rayllianassa , R. amboinensis is not associated with deep-sea wood, but has been found burrowing in sponges or alcyonacean soft corals between 0.5 and 183 m.

Figures

Figure 1. Dactylus of maxilliped 3 of representatives of two callianassoid families. Eucalliacidae. a, Calliaxina kensleyi (Dworschak, 2005), MNHN IU-2016-8084. Callianassidae. b, Caviallianassa moorea sp. nov., UF 28875; c, Paratrypaea sp, MNHN IU-2013-7035; d, Praedatrypaea lobetobensis sp. nov., MNHN IU-2015-109; e, Praedatrypaea orientalis (Bate, 1888), AM P.74473; f, Rayllianassa amboinensis (De Man, 1888), UF 8700; g, Rayllianassa bifida sp. nov., MNHN IU-2013-7137; h, Rudisullianassa pandan sp. nov., MNHN IU-2013-7063; i, Rudisullianassa rudisulcus Komai, Fujita and Maenosono, 2014, MNHN IU-2013-7121; j, Scallasis amboinae Bate, 1888, MNHN IU-2013-12303; k, Spinicallianassa spinicauda (Komai, Maenosono and Fujita, 2014), MNHN IU-2014-2778; l, Spinicallianassa papetoai sp. nov., UF 29280.

Figure 38. Rayllianassa amboinensis (De Man, 1888). a–d, Timor Sea, NMV J53340, holotype of C. sahul, ovigerous female, cl. 4.3 mm. e–h, Papua New Guinea, UF 8700, ovigerous female, 4.3 mm. i, Papua New Guinea, MNHN IU-2013-7079, ovigerous female, 5.2 mm. j, k, Papua New Guinea, MNHN IU-2013-7058, female, 4.0 mm. l–o, Line Is, UF 11678, ovigerous female, 4.2 mm. a, e, i, j, l, telson, uropod; b, h, o, pereopod 3 (arrows show gaps in marginal setae); c, anterior carapace, eyestalks, antennular, antennal peduncles; d, carapace, eyestalk (lateral); f, k, m, major cheliped (mesial); g, n, minor cheliped (mesial). Scale bar = 1 mm.

Figure 39. Rayllianassa amboinensis (De Man, 1888). a–g, Papua New Guinea, MNHN IU-2013-7049, ovigerous female, 4.1 mm; h–m, Papua New Guinea, MNHN IU-2015-989, female, 4.4 mm; n–q, Arafura Sea, NMV J71761, ovigerous female, 9.3 mm (Note scale). a, h, n, telson, uropod; b, i, o, anterior carapace, eyestalks, antennular, antennal peduncles; c, k, p, major cheliped (mesial); d, major cheliped, carpus–dactylus) (upper); e, major cheliped carpus (cross-section, mesial face left); f, minor cheliped (mesial); g, l, q, pereopod 3 (arrows show gaps in marginal setae); j, carapace, eyestalk (lateral); m, maxilliped 3. Scale bars = 1 mm.