Neoleptastacus chaufriassei ( Bodiou & Colomines, 1986 ), 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 : 28-29

Neoleptastacus chaufriassei ( Bodiou & Colomines, 1986)

Arenopontia (Neoleptastacus) chaufriassei Bodiou & Colomines, 1986

Neoleptastacus chaufriassei ( Bodiou & Colomines, 1986) Sak et al. (2008: 412)

Original description. Bodiou & Colomines (1986): 55–59; Figs 1–2 .

Type locality. French Southern and Antarctic Lands (Terres Australes et Antarctiques Françaises), Crozet Islands; Bodiou & Colomines (1986) collected the type material (syntypes in the absence of an explicit designation of a holotype) from two sandy beaches but did not designate the exact type locality: (1) north of Cap Verdoyant on the west coast of Île aux Cochons, and (2) Baie de l’Aventure on the north coast of Île de l’Est. According to ICZN Art. 73.2.3 the type locality encompasses both places where the syntypes were collected.

Body length. 520 μm (♀), 460 μm (♂).

Remarks. Neoleptastacus chaufriassei is one of three species in the acanthus -group that has retained the plesiomorphic armature pattern on P2–P4, the others being N. acanthus and N. huysi ( Table 2 ). Although Bodiou & Colomines (1986) did not explicitly provide the justification for its proposal, the species can readily be distinguished by the unusual armature of the P 5 in both sexes. The presence of a single minute dentiform spine (♀) or process (♂) (instead of the usual two spines) located at the distal margin of the P5, between the inner bipinnate spinous process and the outer marginal seta, is unique in the genus. This condition is vaguely reminiscent of that in N. angolensis comb. nov. ( Kunz 1971: Abb. 38) but the relative position of the two marginal elements (one short spine and one seta) in the latter rules out homology (a similar but more derived condition is shown by N. africanus ; Chappuis & Rouch 1961: Figs 6–7 ). Convergent evolution in reduced P5 armature has also been postulated for N. reductaspina ( Mielke 1987: 344, Abb. 18B, C). An additional character that differentiates N. chaufriassei from its congeners is the length and ornamentation of the inner subdistal seta of P4 exp-3 which is remarkable short and pinnate, a condition shared only with the unrelated N. africanus ( Chappuis & Rouch 1961: Fig. 4 ). In all species for which the P4 exopod was figured (not known for N. longiremis ) it is much longer and distally serrate which, by comparison with other genera that have retained this seta ( Mesopontia , Phreatipontia gen. nov.), appears to be the plesiomorphic condition in the family.

Bodiou & Colomines (1986) do not provide information on the form of the abdominal hyaline frills and their illustration of the caudal ramus is confusing since all seven setae appear to originate from the ventral surface, incuding seta VII which has a conspicuous swollen section halfway (this “renflement” is more likely a misrepresentation of the foliaceous nature of this seta).

The species is only known from two of the Crozet Islands with no variability recorded between sampling sites. Block (1992) cited an unnamed species of Arenopontia in his annotated bibliography of terrestrial and freshwater Antarctic invertebrates but this in reality refers to Bodiou & Colomines’s (1986) description of A. chaufriassei from sandy beaches in the Crozet Islands (see also Pugh et al. 2002).

Figures

FIGURE 1. Neoleptastacus acanthus (Chappuis, 1954) (♀): (A) habitus, dorsal; (B) habitus, lateral; (C) rostrum, dorsal.

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]

FIGURE 4. Neoleptastacus acanthus (Chappuis, 1954) (♀): (A) P1, anterior; (B) P2, anterior; (C) P3, anterior; (D) P4, anterior.

FIGURE 6. Neoleptastacus emendatus sp. nov. (♀): (A) habitus, dorsal; (B) habitus, lateral; (C) anal somite and caudal rami, dorsal; (D) anal somite and right caudal ramus, lateral.

FIGURE 7. Neoleptastacus emendatus sp. nov. (♀): (A) urosome, ventral; (B) antennule, dorsal; (C) antenna, outer; (D) antennary endopod, medial; (E) rostrum, dorsal; (F) midventral hook-like processes [indicated by arrows] on pedigerous somites; (G) hook-like process, lateral. [lateral endopodal spines indicated by arrows in C–D]