Ancylomenes okunoi, Bruce, 2010

Bruce, A. J., 2010, Ancylomenes kuboi and A. okunoi spp. nov. (Decapoda: Pontoniinae), from the Australian Northwest Shelf, Vietnam and the Philippines *, Zootaxa 2372 (1), pp. 169-176 : 172-174

publication ID	https://doi.org/ 10.11646/zootaxa.2372.1.17
DOI	https://doi.org/10.5281/zenodo.5312952
persistent identifier	https://treatment.plazi.org/id/C37F879E-8455-5670-FF64-FAB553F493F5
treatment provided by	Felipe
scientific name	Ancylomenes okunoi
status	sp. nov.

Treatment

Ancylomenes okunoi View in CoL sp. nov.

( Fig. 3 View FIGURE 3 )

Periclimenes tosaensis View in CoL . — Bruce, 1981: 196, fig. 5. — Li & Bruce, 2006: 721 View Cited Treatment .

Material examined. (i) 1 female holotype; 1 male allotype, CLs 5.9, 4.6 mm. FRV Soela, stn. B5, 19°05.0”S 118°50.5’E, Northwest Shelf , Western Australia, 83 m, 29 June 1983, leg. T. Ward, beam trawl, NTM Cr015051 .

Additional, non-type material examined: (ii) 1 male, CL 4.8 mm, FRV Soela , stn. NWS–20, 19°03.5’S, 119°03.6’E, Northwest Shelf , Western Australia, 80 m, beam trawl, 28 April 1983, NTM Cr015045; (iii) 1 female, CL 2.2 mm, FRV Soela, stn NWS–19, 19°04.3’S, 117°47.8’E, Northwest Shelf, Western Australia, 80 m, 27 April 1983, NTM Cr 015046; (iv) 2 ov. females, CL 5.1–5.3 mm, MUSORSTOM 1, NO Vauban, stn 56, 13°53.1’N, 120°08.9’E, Philippines, 129-134 m, 26 March 1976, MNHN Na 3834; (v) 2 ov. females, CL 4.6– 4.8 mm, MUSORSTOM 1, NO Vauban, stn 72, 14°11.0’N, 120°28.7’E, Philippines, 122–127 m, 28 March 1976, MNHN Na 3562 GoogleMaps .

Diagnosis. A medium sized Ancylomenes species , R. 1+7–9/2, rostral elevation 15°, third abdominal tergite posteriorly produced, rounded in profile, non-carinate, second pereiopod fingers dentate, ambulatory dactyli simple, propodi with long slender paired subterminal spines.

Description. Rostrum ( Fig. 3A View FIGURE 3 ) reaching to distal end of middle segment of antennular peduncle, dentition 1+7–9/2, terminal ventral tooth minute, preterminal tooth slightly larger, with articulated epigastric tooth at about 0.23 of CL, well separated from first rostral tooth situated over posterior margin of orbit. Inferior orbital angle ( Fig. 3B View FIGURE 3 ) acutely produced with well developed ventral flange. Third abdominal somite ( Fig. 3C View FIGURE 3 ) acutely produced posteriorly, non-carinate. Female major second pereiopod chela ( Fig. 3D View FIGURE 3 ) with fingers ( Fig. 3E View FIGURE 3 ) about 0.83 of palm length, strongly dentate, 4/5 slightly acute recurved teeth, tips strongly hooked, male chela ( Fig. 3F View FIGURE 3 ) with fingers ( Fig. 1G View FIGURE 1 ) feebly dentate, 1/2 respectively. In holotype, with 4 small slightly recurved teeth on fixed finger and single small tooth opposes gap between two distal teeth of fixed finger.

Third pereiopod ambulatory dactylus ( Fig. 3 View FIGURE 3 IK) with unguis feebly demarcated from corpus, with suggestion of obsolete accessory tooth closely adpressed to base of unguis ( Fig. 3J View FIGURE 3 ); propodus ( Fig. 3H View FIGURE 3 ) with 2-1-1-1 spines from distal end, longer distoventral spine slender, straight, about 0.33 of dactylus length.

Measurements (mm). Holotype female, postorbital carapace length, 4.6; carapace and rostrum, 8.5; total body length,(approx.) 30.0; major second pereiopod chela, 5.0; length of ovum, 0.7.

Systematic position. Closely related to A. tosaensis (Kubo) and A. kuboi sp. nov.. Distinguished by the posteriorly produced third abdominal tergite, well armed fingers of the female second pereiopod and shorter paired distoventral spines on the third ambulatory propodus, with the presence of a vestigial accessory tooth on the dactylus.

Colouration. No data.

Etymology. Named in honour of Dr Junji Okuno, of the Coastal Branch of the Natural History Museum and Institute, Chiba, Japan, in recognition of his contributions to knowledge of the Japanese decapod fauna, particularly of pontoniine shrimps.

Remarks. Specimens (i) each have only a single second pereiopod. Specimen (ii) lacks the rostrum and both second pereiopods; an epigastric spine is present and the third abdominal segment and ambulatory dactyli are as in the type specimens. Specimen (iii) lacks the distal half of the rostrum, has no second pereiopods and only two ambulatory pereiopods. It differs slightly from the type specimens in that the third abdominal tergite is less produced, dorsally angular in transverse section and the fourth ambulatory pereiopod has the longer distoventral spine distinctly more than half the dactylus length. The adpressed vestigial accessory tooth is distinct.

The specimens (iii) and (iv) from the Philippines have been previously reported upon as Periclimenes tosaensis by Bruce (1981).