Chalarostylis brenkei Muhlenhardt-Siegel 2005

Chalarostylis brenkei (Mühlenhardt-Siegel, 2005)

Syn.: Hemilamprops brenkei Mühlenhardt-Siegel, 2005.

Material examined. Type material. ANGOLA BASIN: DIVA I. Sta. 350, 16º14.3'S, 05º26.8'E, 5389 m, 29 Jul 2000, 1 A ♂ (Holotype, ZMH K- 40418). Sta. 318, 22º20.0'S, 03º18.3'E, 5125 m, 0 7 Jul 2000, 1 A ♀ (Paratype, ZMH K- 40419).

Additional material examined. ANTARCTICA: ANDEEP II (ANT-XIX/4). Sta. 132-E, 65°18.25'S, 53°22.79'W, 2082 m, 0 6 Mar 2002, 1 A ♂ (ZMH K- 43180). ANDEEP III (ANT-XXII/3). Sta. 59-E, 67°30.75'S, 00°00.23'W, 4651 m, 14 Feb 2005, 1 SA ♂ (ZMH K- 43186). Sta. 88-E, 68°03.84'S, 20°31.39'W, 4928 m, 27 Feb 2005, 2 SA ♂♂, 1 Juv., 1 Manca (ZMH K- 43182). Sta. 88-S (same data that Sta. 88-E), 2 SA ♂♂ (ZMH K- 43183). Sta. 94-E, 66°39.08'S, 27°09.26'W, 4889 m, 0 2 Mar 2005, 1 SA ♂, 1 Juv. (ZMH K- 43184). Sta. 94-S (same data that Sta. 94-E), 1A ♂ (ZMH K- 43185). Sta. 102-E, 65°18.25'S, 53°22.79'W, 2082 m, 0 6 Mar 2005, 1 A ♂ (ZMH K- 43292). Sta. 110-S, 64°59.20'S, 43°02.05'W, 4698 m, 10 Mar 2005, 1 SA ♂ (ZMH K- 43181). GUINEA BASIN: DIVA II. Sta. 89-6-S, 00°42.95'N, 05°31.29'W, 5142 m, 20 Mar 2005, 1 A ♂ (ZMH K- 43961). ARGENTINE BASIN: DIVA III. Sta. 533-E, 36°00.20'S, 49°01.96'W, 4602 m, 15 Jul 2009, 1 A ♀, 1 SA ♀ (ZMH K- 43179). Sta. 534-S, 36°00.61'S, 49°01.54'W, 4608 m, 16 Jul 2009, 1 SA ♂ (ZMH K- 43189). BRAZILIAN BASIN: DIVA III. Sta. 561-S, 26°34.78'S, 35°13.90'W, 4484 m, 23 Jul 2009, 2 SA ♂♂, 1 Juv. (ZMH K- 43187). Sta. 580-S, 14°58.91'S, 29°56.49'W, 5131 m, 30 Jul 2009, 2 SA ♀♀, 2 SA ♂♂ (ZMH K- 43188).

Redescription adult female (ZMH K-43179)

Total length: 9.4 mm (specimen drawn).

Carapace (Fig. 1 B) rather thin and transparent, with setae on frontal and pseudorostral lobes. Width approximately 0.74 its length. Anterior half with sharp middorsal carina, which has no teeth and in lateral view is slightly convex. Branchial chamber inflated leaving a narrow middorsal depression in between. Pseudorostrum almost 3 times length of ocular lobe, with a few teeth anteriorly. Ocular lobe slender, without lenses. Antero-lateral notch absent, antero-lateral angle rounded.

Pereon shorter than carapace, five segments visible.

Abdomen approximately as long as cephalothorax.

Telson (Figs. 1 B, 2B). Almost twice as long as last abdominal segment, 0.64 as long as uropod peduncle and approximately 1.22 times the length of first article of uropod endopod. With 8–9 cuspidate setae on each side and 3 cuspidate setae distally.

First antenna (Fig. 1 C). Peduncle, first article approximately as long as second and third together, with many simple setae, inner distal corner produced as a lobe with 3 (4?) plumose setae. Second article with many simple setae and 2 plumose setae distally. Third article approximately 0.6 as long as second, with 1 plumose seta on inner distal corner. Main flagellum of 5 articles, last two articles with 1 aesthetasc each. Accessory flagellum of 3 articles (distal one minute), almost reaching distal end of second article of main flagellum.

First maxilliped (Fig. 1 D). Basis short, slightly longer than carpus (including the endite), with a stout setulate seta on inner margin. Merus / carpus articulation at an angle greater than 45˚. Merus slightly longer than basis (excluding the endite), with a stout setulate seta on inner distal corner and 1 large setulate seta on outer distal corner. Carpus with a row of 6 setulo-serrulate setae on inner margin (see detail), several setulate setae on ventral surface and 1 large setulate seta on outer distal corner. Propodus approximately 0.43 as long as carpus, with 4 simple setae on inner distal corner, 2 subterminal setulate setae (on ventral and dorsal surface, respectively), and 2 large setulate setae distally. Dactylus 0.60 as long as propodus, with 2 unequal serrulate setae distally.

First pereopod (Fig. 2 A). Basis 0.44 as long as remaining articles together, with setulate setae on both margins and distally. Ischium spoon shaped, providing a concave surface of articulation on which the proximal inner surface of merus fits, ischium / merus articulation distinctly on ventral surface but hardly visible on dorsal surface; with 5 setulate setae. Merus huge, about as long as basis, with setulate setae on outer margin and distally. Carpus approximately 0.8 as long as propodus. Propodus with a strong simple seta on inner distal corner (this seta is missing in appendage drawn; it is represented in dash lines in Fig. 2 A). Dactylus slightly more than ½ as long as propodus, with 8 strong simple setae, 5 on inner margin (only 3 drawn) and 3 distally. Exopod, flagellum of 8 articles.

Uropod (Fig. 2 B). Peduncle with 19–20 cuspidate setae on inner margin. Endopod approximately 0.80 as long as peduncle, consisting of 3 articles. First article approximately 1.5 times as long as the other two together, with 9– 11 cuspidate setae on inner margin; second article with 2 cuspidate setae on inner margin; third article the smallest, with 2 broom setae and a few tiny setae distally. Exopod slightly shorter than endopod (it reaches approximately half length of third endopod article), of 2 articles; first article slightly longer than second, with 3 elongate cuspidate setae on inner margin; second article with 3 elongate cuspidate setae on inner margin, 4 sockets (setae missing) on outer margin (2 small cuspidate setae and 2 sockets lacking setae on the counterpart), distal end with 3 sockets (setae missing). Counterpart second article with 3 unequal elongate (cuspidate?) setae distally, the longest seta as long as article. These missing setae are represented in dash lines in Fig. 2 B.