A new species in the genus Heteromysoides (Crustacea, Mysida, Mysidae) from Songkhla Lagoon, southern Thailand

Abstract

A new mysid, Heteromysoides songkhlaensis, is reported from shallow water in the Songkhla Lagoon, southern Thailand. The new species is closely similar to H. nana in having a triangular rostrum and the eyestalk without a process at the anteromesial corner. However, the new species can be readily distinguished from H. nana by three setae on the inner margin and five setae on distal margin of the second segment of the mandibular palp; the carpopropodus of the fifth and sixth thoracic endopod of the new species is composed of four articles, and the telson of the new species is distally rounded, shorter than the sixth abdominal somite, and 1.3 times longer than its basal width; the spines on the telson form elongated spines from the distal to posterior margin. The new species also resembles H. dennisi, H. simplex, and H. stenoura; however, it differs by (1) the presence of a rounded distal margin of telson, and (2) absence of a sharp process on the distolateral corner of the eyestalk.

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

“…They noted its close relation to Heteromysoides nana, which is, as I mentioned above, in fact, a species of Deltamysis. By the structure of the mandibular palps, pereopods, uropods, telson and other organs, Heteromysoides songkhlaensis is clearly a member of Deltamysis to which it is herein transferred as Deltamysis songkhlaensis (Yolanda, Sawamoto et Lheknim, 2019) comb. nov.…”

“…Heteromysoides included 11 species (Yolanda et al, 2019). The first described species, Heteromysoides cotti, was originally included in Heteromysis (Calman, 1932;Fage & Monod, 1936;Băcescu, 1941;Clarke, 1955;O.…”

“…An updated diagnosis for Platyops is given in the Additional taxonomic observations section below. Yolanda et al (2019) described the most recent species of Heteromysoides, Heteromysoides songkhlaensis Yolanda, Sawamoto et Lheknim, 2019, again based on the reduction of the ocular cornea. They noted its close relation to Heteromysoides nana, which is, as I mentioned above, in fact, a species of Deltamysis.…”

On the mysid crustacean genus Deltamysis (Mysidae: Heteromysinae), with a new species and a new record from Australia

“…Heteromysoides songkhlaensis Yolanda et al, 2019: 536-542, figs 2-4. Deltamysis songkhlaensis.-Daneliya, 2021 Type material.…”

“…Deltamysis songkhlaensis.-Daneliya, 2021 Type material. Holotype, allotype, and numerous paratypes, Songkhla Lagoon, Thailand, Songkhla Province, Singha-Nakhon District, Tambon Bang Khiat, Ban Bang Khiat, Thale Sap, 7°20'58.68"N 100°25'31.56"E (see Yolanda et al, 2019).…”