Athanas parvus De Man, 1910

Anker, Arthur, 2023, Alpheid shrimps of the genera Athanas Leach, 1814, Athanopsis Coutière, 1897 and Pseudathanas Bruce, 1983 of the coasts of the Arabian Peninsula (Malacostraca: Decapoda: Caridea), Zootaxa 5383 (2), pp. 179-215 : 193-194

Athanas parvus De Man, 1910

( Fig. 7 )

Athanas parvus De Man, 1910: 315 ; De Man 1911: 148, (1915) pl. 1, fig. 4; Tattersall, 1921: 372; Ledoyer, 1970: 126, fig. 11; Al-Kandari et al. 2020: 257, fig. 4.

Athanas Sibogae De Man 1910: 314 ; De Man 1911: 151, (1915) pl. 2, fig. 6.

Athanas sibogae — Banner & Banner 1973: 321, fig. 9; Banner & Banner 1981: 43; Titgen 1982: 80; Banner & Banner 1983: 81.

(Note: selective synonymy, with focus on important morphological accounts and records from the western Indian Ocean)

Material examined. 1 male (cl 2.9 mm), FLMNH UF 71418 , Oman, Masirah Island , 2 km north of Ghab, 20°15’51.6”N / 58°37’26.3”E, coral reef flat, under coral rubble on sand, hand collecting, depth 1.5–2 m, leg. A. Anker, 20.11.2022 [fcn BOMAN-14839] .

Description. For description and illustrations of A. parvus see, for instance, De Man (1910, 1911), Miya & Miyake (1968) and Banner & Banner (1973); see also Fig. 7 .

Colour in life. Body evenly speckled with bright red chromatophores, carapace and pleon with broad, somewhat nerve cord-shaped band composed of bright white and pinkish white chromatophores, extending along mid-dorsal surface from tip of the rostrum to posterior margin of sixth pleonite; antennular peduncles with large white patches; antenna mostly translucent with red spots; chelipeds hyaline with red spotting; remaining pereiopods mostly translucent with occasional red spotting; tail fan bright red ( Fig. 7 ). See also Al-Kandari et al. (2020: fig. 4).

Distribution. Indo-West Pacific from the Red Sea and Madagascar to Japan, Australia and Samoa ( De Man 1911; Miya & Miyake 1968; Banner & Banner 1973, 1985; Chace 1988; Anker 2001; Anker & De Grave 2016; Al-Kandari et al. 2020); apparently first record from Oman (present study).

Ecology. Commonly encountered under rocks, living and dead corals, or in coral crevices, from the lower intertidal to at least 70 m ( Miya & Miyake 1968).

Remarks. Athanas parvus is one of the most common species of the genus, found throughout the Indo-West Pacific. The species can be identified using the combination of the colour pattern ( Fig. 7 ) with the enlarged, ventrally folding chelipeds, and the presence of biunguiculate dactylus on the third to fifth pereiopods. However, no phylogeographic studies on A. parvus , including comparison of the populations from the western Indian Ocean with those from the western Pacific have been performed so far.

Figures

FIGURE 7. Athanas parvus De Man, 1910, male (cl 2.9 mm) from Masirah Island, Oman (FLMNH UF 71418); a, shrimp in life, lateral (left side); b, dorsal. Photographs by the author.