Neocallichirus Sakai, 1988

Poore, Gary C. B., 2023, New records and one new species of Callichiridae (Crustacea, Axiidea) from the Indo-West Pacific, with keys to species of Corallianassa, Lepidophthalmus and Neocallichirus, Memoirs of Museum Victoria (Mem. Mus. Vic.) 82, pp. 71-95 : 81-82

Neocallichirus Sakai, 1988

Remarks. Neocallichirus is the largest of the 17 genera of Callichiridae ( Poore et al., 2019) . It comprises 33 nominal accepted species (DecaNet eds, 2023) of which about half occur in the Indo-West Pacific and 14 in the Caribbean and Atlantic. Sakai’s (2011) key to species is now incomplete and includes species now in other genera; Hernáez et al. (2020) provided a key to seven Western Atlantic species. Species of Neocallichirus are recognised by the uropodal endopod with a straight or slightly convex anterior margin ending in a rounded angle, the posterior margin being more or less continuous with the posterior margin, a telson that tapers regularly to about half its width, and the antennal peduncle being longer than the antennular peduncle. Some of the nominal Indo-West Pacific species are incompletely described and problematic for one reason or another. Most were described from one or few specimens, or incomplete specimens, some possibly from juveniles. The types of some species have been illustrated more than once, e.g. Neocallichirus moluccensis (De Man, 1905) (De Man, 1928a; Kazmi and Kazmi, 1992; Sakai, 1999) but inconsistencies between figures such as these suggest that subtle differences between species are masked. Variation is appreciable for three species that have been collected in sufficient numbers ( Dworschak, 2011a, 2011b, 2018) which, if accepted, would appear to allow other nominal species to be synonymised.

The diagnoses and key to 15 Indo-West Pacific species below rely on direct observations of seven species and published illustrations of the others. Some are difficult to distinguish in isolation. Five nominal species deserve comment and are not included in the key:

Neocallichirus auchenorhynchus Sakai, 2005 is based on a single very small female (cl. 4.4 mm) from an unknown locality. Sakai’s (2005) description of the “frontal margin of carapace showing a neck-like form, with triangular rostrum and a pair of anterolateral projections” ( Sakai, 2005: fig. 37A) is hard to credit because the figure of the lateral view ( Sakai, 2005: fig. 37B) does not show this and is typical of all callichirids. Lack of a type locality, small size, absence of the major cheliped and suspect illustrations argue for treating this name as species inquirenda.

Neocallichirus kenyaensis Sakai, 2015 , is an unavailable name, without an explicit holotype, thereby failing ICZN Articles 16.4 and 72.3. The name was suggested for the female from Kenya identified by Dworschak (2011b) as N. natalensis ( Barnard, 1947) . The blade on the lower margin of the major cheliped is more developed on this 117-mm-long individual ( Dworschak, 2011b, fig. 5E, F) than in the 100-mm-long holotype ( Barnard, 1950: fig. 95g; Sakai, 2015: fig. 23c) but the dactylus is identical. A new name is not needed. Callianassa natalensis Barnard, 1947 was synonymised with N. indicus but Dworschak (2011b) showed it to be valid. Neocallichirus indicus is a synonym of jousseaumei Dworschak (2011b , 2018).

Neocallichirus pola Sakai and Türkay, 2014 , type locality, Red Sea, seems indistinguishable from N. mauritianus ( Miers, 1882) known only from Mauritius. If synonymous, the distribution of N. mauritianus would be extended (see below).

Poore et al. (2019) synonymised Callichiropsis Sakai, 2010 with Neocallichirus . Its only species C. spiridonovi Sakai, 2010 was included by these authors in Neocallichirus , but was based on two small damaged females with major chelipeds too difficult to characterise.

Dworschak (2011b) found no morphological difference between Callianassa (Cheramus) variabilis Edmondson, 1944 from Hawaii and N. jousseaumei , despite unpublished molecular studies that he cited showing a sufficient specific difference. The most recent molecular data, possibly using different genes, found almost no genetic difference between individuals of “ N. jousseaumei ” from Hawaii and Cocos (Keeling) Is relative to differences between individuals from Philippines, Papua New Guinea and Iran ( Robles et al., 2020). While this uncertainty remains, Neocallichirus variabilis ( Edmondson, 1944) is not included in the key to species below.