Rayllianassa sp.

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 : 235

Rayllianassa sp.

Figures 37b , 46

Rayllianassa cf. amboinensis .— Robles et al., 2020: fig. 3 (part).

Material examined by P.C. Dworschak. Philippines, Luzon , 14° 53' N, 121° 45'E, 269–277 m ( MNHN AURORA 2007 stn CP2671), NHMW 25915 * (tissue sample ULLZ 10127 ), (ovigerous female, 4.3 mm) .

Diagnosis. Antennular peduncle about as long as antennal peduncle. Major cheliped merus with simple proximal tooth and carinate along most of lower margin; carpus and merus upper margins carinate; palm upper margin with narrow rounded keel, without tubercles and ridges on distal mesial and lateral margins at the base of fingers; dactylus with blade along cutting edge, apex simple. Pereopod 3 propodus oval, widest proximally. Uropodal exopod widest near midpoint, 1.2 times as long as wide; endopod elongate-oval, twice as long as wide.

Remarks. Peter C. Dworschak (pers. comm., 26 September 2022) provided sketches of this individual that is included in the molecular phylogram of Robles et al. (2020: fig. 3). It is similar to R. huonensis . The major cheliped of the two species are similar (merus with a basal spine, distomesial margin of the palm with a tubercle) but the uropods differ – R. huonensis has a relatively narrower exopod and wider endopod with a long spiniform seta on the dorsal face. Sequences of the two species diverge significantly (12S: 0.031; 16S: 0.050; Table 2). The dorsal carapace and pleon is reddish; the chelipeds have a pale orange distal transverse band on the carpus and palm (fig. 37b).

Figures

Figure 37. Rayllianassa spp. a, R. aurora sp. nov., Philippines, MNHN IU-2016-8126, ovigerous female, 4.4 mm; b, Rayllianassa sp. Philippines, NHMW 25915, ovigerous female, 4.3 mm. (colour photographs by T.-Y. Chan).

Figure 46. Rayllianassa sp. Philippines. NHMW 25915 (ovigerous female, 4.3 mm: a, major cheliped (left, mesial); b, major cheliped distal palm, fingers (lateral); c, minor cheliped (right, mesial); d, minor cheliped distal palm, fingers (lateral); e, right uropod (from drawings by P.C. Dworschak).