Latopilumnus Turkay & Schuhmacher 1985
Creators: name: Ng, Peter K. L.
name: Prema, Mani
name: Ravichandran, Samuthirapandian
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Pilumnidae
Latopilumnus

description: Genus Latopilumnus Türkay & Schuhmacher, 1985
Type species. Latopilumnus tubicolus Türkay & Schuhmacher, 1985, by original designation.
Remarks. The low lateral lobule of the front is a character that would have placed Latopilumnus ajmali n. sp. in Parapilumnus Kossmann, 1877, following the traditional classification (cf. Takeda & Miyake, 1969). Ng (2002) showed that Parapilumnus is not a pilumnid as the type species, Parapilumnus cristimanus (A. Milne-Edwards, 1873) is an acidopsid (see also Ng & Rahayu 2014). Ng (2002) nevertheless argued that the strength of the lateral lobule varies too much to be a useful generic character in any case and opted to just transfer the species then recognised in Parapilumnus to Pilumnus Leach, 1816, s. lato. Ng & Clark (2008) subsequently redefined and revised Latopilumnus and included some species previously assigned to Parapilumnus.
The following characters of L. ajmali n. sp. are typical for species of Latopilumnus: lateral lobule of the front is relatively poorly demarcated, with the frontal margins almost confluent with the supraorbital margin (Figs. 5B, 7A), granulated margins on the anterolateral teeth giving it a serrate appearance (Figs. 5B, 7A), and presence of low serrations on the extensor margin of the P2–P5 merus, with the carpus and propodus distinctly lined with two rows of low, sharp granules (relatively lower in the P5) (Fig. 6F, G).
Six species of Latopilumnus are currently recognised: L. conicus Ng & Clark, 2008, L. guinotae (Deb, 1987), L. malardi (De Man, 1914), L. truncatospinosus (De Man, 1914), L. tuberculosus (Garth & Kim, 1983), and L. tubicolus Türkay & Schuhmacher, 1985 (cf. Ng & Clark 2008). Of these, three are known from the Indian Ocean: L. guinotae (Andaman Islands), L. malardi (Madagascar) and L. truncatospinosus (Madagascar). The generic position of L. guinotae (Deb, 1987) is unclear as it seems to lack most of the generic characters except for the low lateral lobule of the front, and it also appears to more pilose than congeners. Unfortunately, it was only described from one female (cw 7.0 mm, cl 5.0 mm) and the only figure provided is not very informative (cf. Deb 1987: 311, pl. 13 fig. 3). It will need to be re-examined to ascertain its precise generic position.
Some Latopilumnus species are known to be associated with barnacle clumps, dead corals and living hard corals (Türkay & Schuhmacher, 1985). The only known specimen of the present new species, Latopilumnus ajmali n. sp. was found in sponges (Fig. 1B), but it is not clear if it is an obligate symbiont.
description: Published as part of Ng, Peter K. L., Prema, Mani & Ravichandran, Samuthirapandian, 2024, Descriptions of new and rare crabs associated with coral rubble and sponges from Kanyakumari, southeastern Arabian Sea, southern India (Decapoda: Brachyura: Epialtidae and Pilumnidae), pp. 325-341 in Zootaxa 5476 (1) on pages 329-331, DOI: 10.11646/zootaxa.5476.1.26, http://zenodo.org/record/12681830