Chalarostylis Norman, 1879

Alberico, Natalia A., Roccatagliata, Daniel & Mühlenhardt-Siegel, Ute, 2014, Remarks on the deep-sea genus Chalarostylis (Cumacea: Lampropidae), Zootaxa 3753 (4), pp. 323-334 : 324

Genus Chalarostylis Norman, 1879

Diagnosis (emended). First antenna, accessory flagellum shorter than main flagellum. Male second antenna not extending beyond second abdominal segment. First maxilliped, basis short, merus outer distal angle projected forwards providing an oblique edge of articulation with carpus greater than 45º. First pereopod with long and stout merus, and dactylus with a brush of strong simple setae (in some species the propodus also carried a strong simple seta distally). Telson distinctly shorter than uropod peduncles.

Type species. Chalarostylis elegans by monotypy.

Species. C. elegans Norman, 1879 ; C. guanchi ( Reyss, 1978b) ; C. canadensis ( Vassilenko, 1988) n. comb.; C. brenkei ( Mühlenhardt-Siegel, 2005) n. comb.; C. longisetae ( Corbera, 2006) n. comb.

Remarks. Chalarostylis is a deep-sea genus close to Hemilamprops , but easily distinguished from the latter by its stout first pereopod. However, this appendage is usually broken off at the level of the basis-ischium joint in the specimens examined. If the distal part of the first pereopod is lacking, the member of Chalarostylis can be distinguished from those of Hemilamprops by the following combination of characters: the accessory flagellum of the first antenna shorter than the main flagellum, the telson distinctly shorter than the uropod peduncles, and the male antenna not reaching beyond the second abdominal segment. In addition, the first maxilliped with its short basis and a merus / carpus articulation greater than 45º is proposed in this study as an additional diagnostic character to recognize the members of Chalarostylis . It is worth noticing that C. elegans (the type species of the genus), C. canadensis n. comb. and C. brenkei n. comb. show the first maxilliped characteristic of the genus (see Gerken & McCarthy 2009; Vassilenko 1988; and Fig. 1 D herein). In addition, we have corroborated that the POLYGAS specimens herein designated as Chalarostylis sp. A also have this particular first maxilliped, i.e., with a short basis and a merus / carpus articulation greater than 45º.

Figures

FIGURE 1. Chalarostylis brenkei (Mühlenhardt-Siegel, 2005). A, first maxilliped, sketch showing measurement of merus / carpus angle. Adult female (ZMH K- 43179): B, habitus. C, first antenna. D, first maxilliped and detail of a carpal setulo-serrulate seta. Scales: B, C, 1 mm. D, 0.5 mm.