Neoleptastacus trisetosus ( Mielke, 1982a ), 2008

Sak, Serdar, Karaytuğ, Süphan & Huys, Rony, 2024, Review of Neoleptastacus Nicholls, 1945 (Harpacticoida, Arenopontiidae), including an updated key to species and proposal of Phreatipontia gen. nov., Zootaxa 5525 (1), pp. 1-66 : 26

Neoleptastacus trisetosus ( Mielke, 1982a)

Arenopontia trisetosa Mielke, 1982a

Pararenopontia trisetosa ( Mielke, 1982a) Bodiou & Colomines (1986: 61)

Arenopontia (Arenopontia) trisetosa Mielke, 1982a : Bodin (1988: 166)

Arenopontia (Pararenopontia) trisetosa Mielke, 1982a : Bodin (1997: 165)

Neoleptastacus trisetosus ( Mielke, 1982a) Sak et al. (2008: 412)

Original description. Mielke (1982a): 42–48; Abb. 25–27, 28 (distribution map).

Additional description. Mielke (1982b): 200–201; Fig. 2D .

Type locality. Ecuador, Galápagos, Barrington ; strongly exposed sandy beach, north side of island .

Body length. 230–270 μm (♀), 250–260 μm (♂) [ Mielke 1982a]; 280–290 μm (♀), 260–280 μm (♂) [ Mielke 1982b].

Remarks. Mielke (1982a) reported N. trisetosus from a second beach on Barrington and from Puerto Nuñez on Santa Cruz (Galápagos archipelago). The specimens from the latter site differed slightly in the length of the outer spine on P2 exp-2 ( Mielke 1982b). Members of the genus Neoleptastacus typically display well developed hyaline frills on the abdominal somites which are characteristically incised, forming rectangular or apically rounded lappets. Mielke (1982a) failed to observe such frills in N. trisetosus but reported a plain frill on the penultimate somite (his Abb. 27A). The long pectinate seta on P4 enp-2 was described as an articulating element which is possibly based on an observational error since it is typically fused at the base in other members of the genus. The only ovigerous female found by Mielke (1982a) had one egg in the egg-sac but this is most likely due to damage. Mielke (1982b: Fig. 2D ) provided a more accurate drawing of the caudal ramus which confirms the presence of coarse spinules near the base of dorsal seta VII (as in N. supersetosus sp. nov. and possibly N. panamensis sp. nov. —see below).

Mielke (1982b) reported specimens from two localities along the Pacific side of Panamá which he identified as N. trisetosus despite some morphological differences. The Panamanian population is here treated as a discrete species, N. panamensis sp. nov., which can be differentiated from N. trisetosus by differences in the female genital field, P1, P2, P4 and caudal ramus ornamentation (see below). Both species differ from other members in the genus by the discrete inner spine of the P 5 in both sexes (which forms a spinous process in other congeners).

Figures

FIGURE 2. Neoleptastacus acanthus (Chappuis, 1954): (A) habitus (♂), dorsal; (B) anal somite and caudal rami (♀), dorsal; (C) anal somite and left caudal ramus (♀), lateral; (D) antenna (♀), medial; (E) antennary endopod (♀), outer. [Lateral spines of antennary endopod indicated by arrows in D–E]