Parastenheliidae (Willen, 2000)

Huys, Rony & Mu, Fanghong, 2021, Johnwellsia, a new intertidal genus of Parastenheliidae (Copepoda, Harpacticoida) from the Taiwan Strait, China, including a review of the family and key to genera, Zootaxa 5051 (1), pp. 236-318 : 304-305

Key to genera of Parastenheliidae

1. P3–P4 exp-3 with 4–5 elements; P3–P4 enp- 2 ♀ without inner seta..............................................2.

– P3–P4 exp-3 with 6–8 elements; P3–P4 enp- 2 ♀ with inner seta................................................4.

2. Antennule ♀ 8-segmented; proximal endopodal segment of antenna without abexopodal seta; P1 exopod 2-segmented; P1 endopod without area of thin cuticle near insertion of inner seta........................ Paraleptomesochra Wells, 1967 .

– Antennule ♀ 9-segmented; proximal endopodal segment of antenna with abexopodal seta; P1 exopod 3-segmented; P1 endopod with area of thin cuticle near insertion of inner seta............................ Psammoleptomesochra Mielke, 1994a .

3. P1 inner basal spine sexually dimorphic; P2 enp-3 with two inner setae............................ Foweya Gee, 2006 .

– P1 inner basal spine not sexually dimorphic; P2 enp-3 with 0–1 inner seta(e)......................................4.

4. P1 exopodal segments subequal..........................................................................5. P1 exp-2 much longer than exp-1 and -3...................................................................8.

5. Antennule ♀ with segments distal to aesthetasc-bearing (4th) segment significantly compressed; antennule ♂ with characteristic backwardly directed spiniform element on second segment, either displaying a serrate or flagellate tip; antenna sexually dimorphic, in ♂ with abexopodal seta of allobasis and lateral setae of exopodal segments enlarged and highly plumose; distal segment of antennary exopod with three elements; maxillipedal syncoxa with only one seta; P2 exp-3 with two inner setae; outer spine on P3 enp- 3 ♂ reduced in size............................................ Thalestrella Monard, 1935a .

– Antennulary segments ♀ distal to aesthetasc-bearing (4th) segment not displaying compressed appearance; antennule ♂ without such modified element on second segment; antenna without sexual dimorphism; distal segment of antennary exopod with at least four elements; maxillipedal syncoxa with 2–3 setae; P2 exp-3 with one inner seta; outer spine of P3 enp- 3 ♂ not sexually dimorphic...........................................................................................6.

6. Rostrum very large, reaching at least to halfway 4th segment of antennule; distal element on mandibular basis enlarged and spiniform; P5 baseoendopod ♀ with transverse striae along inner margin of endopodal lobe, outermost seta minute; P3 endopod ♂ with three inner setae................................................................. Porirualia gen. nov.

– Rostrum much smaller, reaching at most to distal margin of 2nd segment of antennule; distal element on mandibular basis setiform; P5 baseoendopod ♀ without transverse striae along inner margin of endopodal lobe, outermost seta well developed; P3 endopod ♂ with 1–2 inner seta(e).....................................................................7.

7. Antennary allobasis without abexopodal seta; antenna with one lateral element on exp-2; maxillipedal basis with two setae; P3 endopod ♂ without spinous apophysis on enp-3; P5 exopod ♂ with four elements.................. Johnwellsia gen. nov.

– Antennary allobasis with abexopodal seta; antenna with two lateral elements on exp-2; maxillipedal basis with one seta; P3 endopod ♂ with spinous apophysis on enp-3; P5 exopod ♂ with 6–7 elements...... Parastenhelia Thompson & Scott, 1903

8. Lateral spines of distal segment of antennary endopod penicillate; P1 exp-3 and enp-2 with penicillate elements............................................................................................ Penicillicaris gen. nov. Lateral spines of distal segment of antennary endopod pinnate; elements of P1 exp-3 and enp-2 non-penicillate...........9.

9. Endopodal claw of maxilliped spatulate, fringed with series of densely arranged serrations around inner margin and rounded apex; P5 exopod ♂ 2-segmented, with five elements........................................ Karaytugia gen. nov.. Endopodal claw of maxilliped tapering gradually and ending in pointed tip, without serrations around inner margin; P5 exopod ♂ 1- or 3-segmented, with 6–7 elements.............................................. Microthalestris Sars, 1905 .