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) Author Anker, Arthur Universidade Federal de Pelotas (UFPEL), Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Campus Universitário Capão do Leão, RS, 96010 - 610, Brazil & Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia text Zootaxa 2023 2023-12-11 5383 2 179 215 https://www.mapress.com/zt/article/download/zootaxa.5383.2.5/52448 journal article 10.11646/zootaxa.5383.2.5 1175-5326 10350767 7E434B40-6346-4E6D-BC55-38EBAE24BD52 Athanas iranicus Anker, Naderloo & Marin, 2010 ( Fig. 5 ) Athanas iranicus Anker et al. 2010: 54 , figs. 1–4; Naderloo & Türkay 2012: 12; Ashrafi et al . 2020a: 520 ( Table 1 ). Material examined . 1 female (cl 3.6mm ), FLMNH UF68857 , Oman , east of Muscat, Bandar Khayran , 23°30’32.3”N / 58°43’58.0”E , mangrove, muddy sand and mud, depth 0–1 m , suction pump, in burrow, leg. A. Anker et al ., 01.02.2022 [fcn BOMAN-09986] ; 1 female (cl 2.8 mm ), FLMNH UF 68860 , same collection data as for previous specimen [fcn BOMAN-09985]; 1 ovig. female (cl 3.6 mm ), FLMNH UF 68858 , Oman , east of Muscat, Bandar Khayran , 23°30’32.5”N / 58°43’53.5”E , mangrove and adjacent mudflat, at night, depth at low tide 0–1 m , suction pump, in burrow, leg. A. Anker , 04.02.2022 [fcn BOMAN-11371] ; 1 female (cl 2.5 mm ), FLMNH UF 68861 , same collection data as for previous specimen [fcn BOMAN-11355] . Description . See Anker et al. (2010) for description and illustrations; some taxonomic remarks on the Omani material are provided below, whereas the species’ colour pattern is described and illustrated for the first time ( Fig. 5 ). Colour in life . Background semi-opaque whitish; carapace and pleon speckled with numerous blotches of red chromatophores, except for large part of branchial area of carapace; dorsal surface of carapace, including rostral and post-rostral area, with large patches of buff white chromatophores; pleon with broad mid-dorsal band of buff white colour stretching from anterior margin of first pleonite to posterior margin of sixth pleonite, and extending as transverse bands on first, third, fourth (slightly) and sixth (forming large transverse patch) pleonites; some red chromatophores visible within buff white mid-dorsal band or patches on carapace and pleon; telson with proximal two-thirds bright red and distal one-third conspicuously yellowish white; antennular peduncle with bright red chromatophores on stylocerite and some parts of first article, and bright yellow white chromatophores on most of remaining peduncle and proximal flagella; antennae largely translucent with bright red chromatophores on scaphocerite and carpocerite, distal area of scaphocerite yellow white, flagellum colourless; major cheliped hyaline white with patches of red chromatophores, especially on chela; minor cheliped and remaining pereiopods, as well as pleopods, mostly whitish; uropods with proximal half deep red and distal half conspicuously yellowish white (similar to telson); eggs red orange ( Fig. 5 ). Distribution . Iran : Qeshm Island (Anker et al . 2010); Oman : Bandar Khayran east of Muscat (present study). Ecology . The four Omani specimens of A. iranicus were collected in muddy mangrove channels from burrows of unknown hosts. The syntopic macrofauna included large burrowing snapping shrimps ( Alpheus spp. ) and their associates (e.g., Salmoneus rostratus Barnard, 1962 ), several species of fossorial crabs ( Macrophthalmus spp. ), and callianassid ghost-shrimps. The holotype from Iran was collected, according to the label accompanying the specimen, in “muddy sand with shell fragments” (Anker et al. 2010). FIGURE 5. Athanas iranicus Anker, Naderloo & Marin, 2010 , ovigerous female (cl 3.6 mm) from Bandar Khayran, Oman (FLMNH UF 68858); a, shrimp in life, right antennal flagellum broken, dorsal; b, same, lateral (left side). Photographs by the author. Remarks . Athanas iranicus is a distinctive member of the genus Athanas , due to its unique combination of morphological features. Especially diagnostic for A. iranicus are the very short rostrum; the greatly reduced orbital teeth; the robust, somewhat unequal and assymmetrical chelipeds, which are furnished with dense fields of fine setae, one extending from the carpus to the proximal portion of the propodus and one on the fingers; and the relatively robust walking legs (Anker et al. 2010). The species was hitherto known only from the type locality in Iran ( Qeshm Island north of Strait of Hormuz ) and based on a single male holotype . The material from Bandar Khayran represents the second only finding of A. iranicus and extends the previously known distribution range of the species from Iran to Oman . It is likely that A. iranicus is more widely distributed in the north-western Indian Ocean, although it has not been collected at other sampled localities along the eastern and southern coasts of Oman ( Dhofar and Masirah Island) (A. Anker, pers. obs.). All Omani specimens of A. iranicus are females, including one ovigerous female ( Fig. 5 ). They present no significant discrepancies from the description of the male holotype . In all but one specimen , the chelae possess two distinct areas of fine dense setae, as described above; these setae are only missing (or at least are very poorly developed) in the smallest female (cl 2.5 mm ) (FLMNH UF 68861). The previously unknown colour pattern of A. iranicus ( Fig. 5 ) is most similar to the colour patterns of A. shawnsmithi Anker, 2011 , A. daviei Anker, 2011 (cf. Anker 2011: fig. 8A–F; Anker et al. 2015: fig. 9) and the above-described A. claereboudti sp. nov. ( Fig. 3 ). On the other hand, the stomatopod-associated species A. ahyongi Anker & Komai, 2010 , A. manticolus Ďuriš & Anker, 2014 and A. philippei Anker & Ďuriš 2022 , as well as the Alpheus -associated A. alpheusophilus Marin, 2017 and the above-reported A. cf. dentirostris , have very different colour patterns (cf. Fig. 4 ; Anker & Komai 2010 : fig. 6; Ďuriš & Anker 2014 : fig. 6; Marin 2017 : fig. 6; Anker & Ďuriš 2022 : figs. 5, 6A, B).