Parabetaeus hummelincki ( Schmitt, 1936 )

Anker, Arthur, Tavares, Marcos & Mendonça, Joel B., 2016, Alpheid shrimps (Decapoda: Caridea) of the Trindade & Martin Vaz Archipelago, off Brazil, with new records, description of a new species of Synalpheus and remarks on zoogeographical patterns in the oceanic islands of the tropical southern Atlantic, Zootaxa 4138 (1), pp. 1-58 : 32-33

Parabetaeus hummelincki ( Schmitt, 1936)

Alpheopsis hummelincki Schmitt 1936: 364 , pl. 11, fig. 1.

Neoalpheopsis hummelincki— Chace 1972: 78.

Parabetaeus hummelincki — Nomura & Anker 2001: 52; Anker 2007: 34, fig. 7, 8b, c; Anker 2011: 1, figs. 1–3. Neoalpheopsis euryone— Manning & Chace 1990: 17 [not P. euryone (de Man, 1910) ].

Material examined. Brazil: 1 ovig. female (missing both chelipeds), USNM 310832, Espírito Santo, off Vitória, Trindade Island, between Baixios do Sueste and Parcel das Tartarugas, 20°30’S – 29°20’W, in tide pool, rotenone, depth: 1–2 m, coll. unknown, 16.i.1976 [material reported in Anker (2007)]. Size of female: cl 5.5 mm.

Description. See Schmitt (1936) for original description and figures, and Anker (2007, 2011) for additional illustrations.

Distribution. Amphi-Atlantic (but see below): São Tomé & Príncipe; Ascension Island; throughout Caribbean Sea; Bermuda; Brazil: Atol das Rocas , Trindade Island (Anker 2007, 2011).

Ecology. Coral and rocky reefs and adjacent habitats with abundance of coral rubble, rocks with coralline algae etc.; usually dwelling in spaces under coral rocks; intertidal to at least 12 m.

Remarks. The alpheid material collected during the ProTrindade and TAAF MD55 campaigns does not contains a single individual of Parabetaeus hummelincki , suggesting that this species may be very rare in Trindade Island. Thus, Anker’s (2007) record of P. hummelincki based on a single incomplete ovigerous female (see material examined) presently remains the only record of this species from the Trindade & Martin Vaz Archipelago.

The taxonomic status of P. hummelincki was briefly discussed by Nomura & Anker (2001), who decided to tentatively keep this taxon as an Atlantic species distinct from the Indo-Pacific P. e u r y on e (de Man, 1910). The few morphological differences between the two nominal species appear to be minimal, affecting mainly the armature of the cheliped fingers. However, if these differences are shown to be inconsistent by examination of more material, it would result in a single pantropical species, P. euryone , as it was treated by Manning & Chace (1990). Therefore, a genetic comparison between the Atlantic and Indo-Pacific populations of Parabetaeus is highly desirable to definitively conclude about the status of P. hummelincki and of the two other Indo-West Pacific species of the genus ( Anker 2015).