Three new species of Heteromysis (Mysida, Mysidae, Heteromysini) from the Cape Peninsula, South Africa, with first documentation of a mysid-cephalopod association

Abstract

Faunistic studies in sublittoral and littoral marine habitats on the Cape Peninsula, South Africa, have yielded three new species belonging to the genus Heteromysis, subgenus Heteromysis: H. cancelli sp. n. associated with the diogenid hermit crab Cancellus macrothrix Stebbing, 1924, and H. fosteri sp. n. extracted from ‘empty’ urchin and gastropod shells. The first documented mysid-cephalopod association is reported for H. octopodis sp. n. which was found in dens occupied by Octopus vulgaris Cuvier, 1797, but was also captured from tide pools. The three new species differ from previously known E. Atlantic species, among other characters, by a single spine on the endopods of uropods in combination with large cornea and absence of median sternal processes on thoracic somites. They are also characterized by a white stripe along the dorso-lateral terminal margin of the eyestalks in living specimens. The new species appear quite similar to each other, but are distinguished by different depths of the telson cleft, different distributions of spines on the lateral margins of the telson, different numbers of segments on thoracic endopod 4, and by differently modified setae on the carpus of the third thoracic endopod, as well as on the carpopropodus of the fourth endopod. An updated key to the species of Heteromysis known from the E. Atlantic is given.

A new species of <i>Heteromysis</i> (Mysida: Mysidae) from public coral reef aquaria in Vienna, Austria

“…Small red chromatophore spots widely scattered over the body, with greatest density above the foregut and along the alimentary canal. While not proven here, we cannot exclude that expansion of the red chromatophore spots results in a red tinge of the entire body (Wittmann & Griffiths, 2017) as often observed in species of Heteromysis. The iridescence of bodies and appendages (Fig.…”

“…Each cercopod bears several small spines with apically increasing size. Size of cercopods measured without spines is 0.5-0.8% body length (n 6) thus much smaller than for example in Heteromysis (Heteromysis) cancelli Wittmann & Griffiths, 2017, whose cercopods are about 9% body length (Wittmann & Griffiths, 2017: Fig. 3N).…”

On the Mysid crustacean genus Heteromysis (Mysidae: Heteromysinae) of the Tasman Sea, with notes on the tribe Heteromysini

“…Ischiomysis had an acute process on the preischium of the pereopod 6 and the flagellated spiniform setae on its ischium, and the penes with large apical lobes, again absent in Heteromysis. The finding of three species of Heteromysis with the endopod 3 carpopropodus not stronger than the merus also excluded the stoutness of the carpopropodus from the diagnostics of the genus (Wittmann & Griffiths, 2017).…”

“…The diagnostics of Heteromysis changed again with description of two genera, Retromysis Wittmann, 2004 andIschiomysis Wittmann, 2013 (Wittmann, 2004(Wittmann, , 2013Wittmann & Wirtz, 2017;Wittmann & Griffiths, 2017). The former genus had special modifications of the male process, the setae of the antennular peduncle and the sternal process on the pereonite 8 of the female absent in Heteromysis.…”

“…The genus Heteromysis contains small, somewhat secretive, incidentally collected crustaceans (Clarke, 1955), associated with various benthic invertebrates: sponges, hydroids, corals, gorgonians, ophiuroids, hermit crabs, mollusc shells, cephalopods and ascidians (Brattegard, 1970;Wittmann et al, 2014;Wittmann & Griffiths, 2017). The name (from Greek "hetero-", meaning "different", and "mysid") denotes differentiation of pereopods, particularly the first and, to certain extent, the second pair.…”