Neoleptastacus, Nicholls, 1945, Nicholls, 1945

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 : 46-47

Key to species

Redefinition of the generic boundaries in the Arenopontiidae ( Sak et al. 2008) and addition of new species have outdated the keys by Lang (1965), Bodiou & Colomines (1986), Karanovic (2000) and Wells (2007). Neoleptastacus accraensis and N. secundus (both species inquirendae) are included in Table 2 but not in the updated key below. Identifications made with this key must be confirmed by reference to the original descriptions in the literature.

1. Anal somite with paired dorsolateral spinous spurs or processes................................................2.

Anal somite without paired dorsolateral spurs or processes...................................................13.

2. Abdominal somites with integumental pattern of rectangular plates dorsally and ventrally; P2 enp-2 without inner seta.....3.

Abdominal somites without conspicuous surface sculpturing; P2 enp-2 with inner seta..............................4.

3. P3 enp-2 with two distal elements; P5 of both sexes with four articulating setae/spines................... N. ornamentus .

P3 enp-2 with one distal element; P5 of both sexes with three articulating setae/spines................... N. reductaspina .

4. P3 enp-2 with two distal elements........................................................................5.

P3 enp-2 with one distal element.........................................................................7.

5. P1 exp-3 with three setae/spines.................................................................... N. huysi .

P1 exp-3 with four setae/spines..........................................................................6.

6. P1 endopod clearly longer than exopod; P3 enp-2 about half the length of enp-1; P5 of both sexes with one seta and two short spines between inner spinous process and outer basal seta............................................ N. acanthus .

P1 endopod as long as exopod; P3 enp-2 only slightly shorter than enp-1; P5 of both sexes with one seta and one spur between inner spinous process and outer basal seta...................................................... N. chaufriassei .

7. Sternal plates of somites bearing P1–P4 with midventral hook-like processes..................... N. emendatus sp. nov.

Sternal plates of somites bearing P1–P4 without such posteriorly directed processes................................8.

8. Paired spinous processes on anal somite straight and backwardly directed.........................................9.

Paired spinous processes on anal somite dorsally recurved....................................................10.

9. P1 endopod 1.15 times as long as exopod; P5 elongate in both sexes, length/maximum width ratio 3.0 (♀) and 3.5 (♂), respectively................................................................................ N. longiremis .

P1 endopod 1.30 times as long as exopod; P5 much shorter in both sexes, length/maximum width ratio 1.7 (♀) and 2.25 (♂), respectively............................................................................. N. rectus sp. nov.

10. P1 endopod shorter than exopod........................................................ N. abbreviatus sp. nov.

P1 endopod at least as long as exopod....................................................................11.

11. P1 endopod as long as exopod; spinous process on caudal ramus relatively short, about 35% of ramus length.................................................................................................. N. chilensis sp. nov.

P1 endopod 1.25–1.30 times as long as exopod; spinous process on caudal ramus longer, about 45–55% of ramus length..12.

12. P1 enp-1 1.25 times as long as enp-2; P 5 ♀ twice as long as maximum width; terminal process of caudal ramus dorsally recurved.................................................................................... N. gussoae .

P1 enp-1 1.65 times as long as enp-2; P 5 ♀ 2.7 times as long as maximum width; terminal process of caudal ramus not dorsally recurved.................................................................................... N. indicus .

13. P1 exopod 2-segmented...............................................................................14.

P1 exopod 3-segmented...............................................................................16.

14. P5 inner spine at least partly delimited at base; P 6 ♂ with one seta.............................................15.

P5 inner spine fused at base, forming spinous process; P 6 ♂ with two elements.................. N. supersetosus sp. nov.

15. P2 exp-2 outer spine shorter than exopod; P2 endopod shorter than exp-1, flask-shaped; P4 exp-3 four times as long as maximum width, with inner seta arising from distal fifth of inner margin......................................... N. trisetosus .

P2 exp-2 outer spine distinctly longer than exopod; P2 endopod as long as exp-1, subrectangular and slightly tapering in distal third; P4 exp-3 2.75 times as long as maximum width, with inner seta arising from middle third of inner margin............................................................................................ N. panamensis sp. nov.

16. P3 endopod 1-segmented, with one distal element..........................................................17.

P3 endopod 2-segmented, enp-2 with two elements (outer one fused at base).....................................19.

17. P1 exp-3 with four elements; P2 endopod 2-segmented; P4 exp-3 without inner seta....................... N. australis .

P1 exp-3 with three elements; P2 endopod 1-segmented; P4 exp-3 with inner seta.................................18.

18. Inner spinous process of P 5 ♀ distinctly curved outwardly (unknown in ♂); terminal process of caudal ramus dorsally recurved........................................................................ N. angolensis comb. nov.

Inner spinous process of P 5 ♀ / ♂ and terminal process of caudal ramus straight........................... N. africanus .

19. P4 exp-3 without inner seta.................................................................... N. pacificus .

P4 exp-3 with inner seta...............................................................................20.

21. Urosome (except anal somite) with distinct surface ornamentation consisting of elongate rectangular plates............................................................................. N. clasingi .

Urosome without conspicuous surface ornamentation........................................................22.

22. Caudal ramus with dorsolateral spur near base of seta VII....................................................23.

Caudal ramus without dorsolateral spur near base of seta VII..................................................24.

23. Lappets of abdominal hyaline frills semi-incised obtusidigitate; inner seta of P2–P3 enp-2 longer than endopod; P5 three times as long as wide, with naked spinous process........................................................ N. spicatus .

Lappets of abdominal hyaline frills denticulate; inner seta of P2–P3 enp-2 shorter than endopod; P5 about 2.5 times as long as wide, with pinnate spinous process.......................................................... N. spinicaudatus .

24. P1 endopod distinctly longer than exopod...................................................... N. ishikarianus .

P1 rami equally long............................................................ N. pseudishikarianus sp. nov.