Neoleptastacus panamensis, Sak & Karaytuğ & Huys, 2024

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 : 36-37

Neoleptastacus panamensis sp. nov.

https://zoobank.org/ F27ED4EA-EC4C-4238-AB97-8414660E0190

Arenopontia trisetosa Mielke, 1982a sensu Mielke (1982b)

Original description. Mielke (1982b —as Arenopontia trisetosa ): 200–201; Fig. 2A–C, E .

Type locality. Panamá, Pacific seaboard, Panamá Province. Mielke (1982b) collected his specimens from two sandy beaches west of Panamá City, i.e. Playa Nueva Gorgona and Playa Río Mar , but did not specify which site the illustrated female specimen (here designated as the holotype) originated from .

Body length. 280–290 μm (♀), 260–280 μm (♂) [ Mielke 1982b].

Etymology. The specific epithet refers to the geographical place of collection (in this case the country of origin) of the name-bearing type.

Remarks. Mielke (1982b) noted several differences between the type population of N. trisetosus from the Galápagos ( Mielke 1982a) and morphologically similar but not identical specimens from the Pacific seaboard of Panamá. Although he viewed these differences as a reflection of intraspecific variability, we consider them as sufficient evidence to attribute separate specific rank to the Panamanian material. The marked and consistent difference in female genital field structure may indicate that the Panamanian population is reproductively isolated from the Galápagos one. In the former the copulatory duct [misinterpreted as the seminal receptacle by Mielke (1982b)] is markedly longer than in the Galápagos specimens. Additional morphological differences include (1) proportional lengths and slenderness of P1 segments with enp-1 being comparatively longer in the Galápagos population (enp-1/exp-1 length ratio 1.8 vs 1.25; enp-1:enp-2 length ratio 1.4 vs 1.15; endopod/exopod length ratio 1.3 vs 1.1), (2) the length of the outer spine on P2 exp-2 which is as long as the entire exopod and reaches well beyond the tip of the outer spine of exp- 3 in the Panamanian population [vs distinctly shorter than the exopod and not reaching beyond the outer spine of exp-3 although some specimens from Puerto Nuñez on Santa Cruz display a longer spine but not to the same degree according to Mielke (1982b)]), (3) the segment representing the P2 endopod is as long as exp-1 and subrectangular in shape and tapers only slightly distal to the insertion of the inner seta (vs shorter than exp-1 and distinctly flask-shaped), and (4) all exopodal segments of P4 are comparatively longer in the Panamanian population (exopod/endopod length ratio 2.6 vs 2.25) and the inner seta on exp-3 inserts more distally (at> 80% of the inner margin length vs 55%).

The female specimen illustrated by Mielke (1982b: Fig. 2B, C, E ) and deposited in the Zoologisches Institut und Museum der Universität Göttingen is here designated as the holotype of N. panamensis sp. nov. in accordance with ICZN Arts 16.4, 72.5.6 and 73.1.4. The species can be differentiated by the characters listed above (ICZN Art. 13.1). Although Mielke (1982b) did not illustrate the caudal ramus of N. panamensis sp. nov., it is likely that it resembles the condition shown by him (his Fig. 2D ) for N. trisetosus , i.e. with coarse spinules around the base of seta VII (as in N. supersetosus sp. nov. (see below).

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]