Hedgpethia Turpaeva, 1973

Sabroux, Romain, 2025, The genus Hedgpethia Turpaeva, 1973 (Pycnogonida: Colossendeidae): a review and a new species, European Journal of Taxonomy 1026, pp. 147-170 : 163-165

Identification key to worldwide species of Hedgpethia Turpaeva, 1973

Below is an identification key for all Hedgpethia , the backbone of which is modified from the key of Stock (1970) for the species of the “ articulatum -group” Rhopalorhynchus [ = articulatum section in Stock 1958], that were later assigned to Hedgpethia .

1. Ocular tubercle rudimentary. Eyes absent ........................................................................................ 2

– Ocular tubercle and eyes well developed .......................................................................................... 3

2. Tibia 1 longer than tibia 2 or femur. Abdomen a small ventral knob ... H. articulata ( Loman, 1908)

– Tibia 1 shorter than tibia 2 or femur. Abdomen about twice as long as wide .. H. nasica Child, 1994

3. Ventral margin of tarsus and propodus without spines ..................................................................... 4

– Ventral margin of tarsus and propodus with a closely set row of spines .......................................... 7

4. Ocular tubercle a tall cone, at least thrice as high as base width. Oviger’s article 10 with a large spine opposing the terminal claw, forming a subchelate structure ........... H. californica ( Hedgpeth, 1939)

– Ocular tubercle not higher than twice as base width. No enlarged oviger spine, an no subchelate structure on the distal oviger articles ................................................................................................ 5

5. Tarsus slightly longer than propodus ........................................................ H. dofleini ( Loman, 1911)

– Tarsus shorter than propodus ............................................................................................................ 6

6. Ocular tubercle conical. Legs articles smooth. Proboscis without narrowing of its inflated part around proximalmost third .......................................................................................... H. calva Arango, 2009

– Ocular tubercle rounded with tapering tip, legs spinous. Proboscis inflated section narrowed at proximalmost third .................................................................................... H. dampieri ( Child, 1975)

7. Tarsus distinctly shorter than propodus ............................................................................................ 8

– Tarsus as long as to distinctly longer than propodus ...................................................................... 14

8. Main claw about as long as propodus ...................................................... H. eleommata Child, 1998

– Main claw less than half as long as the propodus ............................................................................. 9

9. Proboscis cylindrical or tubular in shape, abdomen horizontal……………. H. caudata Turpaeva, 1993

– Proboscis inflating medially, constricted at base, tapering distally ................................................ 10

10. Proximal constriction of the proboscis developed as a long stalk. Ocular tubercle about 4 × as high as base width ............................................................................................. H. atlantica ( Stock, 1970)

– Proximal constriction of the proboscis not developed as a stalk. Ocular tubercle no more than thrice as tall as base width .........................................................................................................................11

11. Posterior margin of trunk segments 1–3 carrying one rounded dorsomedian tubercle each ............... ............................................................................................... H. brevitarsis ( Losina-Losinsky, 1958)

– Posterior margin of trunk segments 1–3 flaring, without dorsomedian tubercle ............................ 12

12. Proboscis flask-shaped, almost pipette-like distally; ocular tubercle a low cone, about as long as base width ............................................................................................................... H. tibialis Stock, 1991

– Proboscis pyriform, gently tapering from its widest point to the tip; ocular tubercle a cone, about twice as tall as base width ............................................................................................................... 13

13. Space separating lateral processes 2–4 wider than their own diameter, proximal constriction of the proboscis forming a short stalk with parallel sides ................................ H. filamentus Staples, 2019

– Space separating lateral processes 2–4 smaller than their own diameter, proximal constriction not forming a stalk ............................................................................................... H. shalei Staples, 2019

14. Anterior margin of cephalic segment with two tubercles ............................................................... 15

– Anterior margin of cephalic segment smooth ................................................................................. 17

15. Main claw half as long as propodus ................... H. spinosa Takahashi, Kajihara & Mawatari, 2012

– Main claw nearly as long as propodus ............................................................................................ 16

16. Posterior margin of trunk segments 1–3 carrying one pointy dorsomedian tubercle each ................. .............................................................................................................. H. bicornis (Turpaeva, 1958)

– Posterior margin of trunk segments 1–3 flaring, without dorsomedian tubercle ................................ .............................................................................................. H. magnirostris Arnaud & Child, 1988

17. Proximal constriction of the proboscis as a long stalk, about as long as 2 nd trunk segment ............... ................................................................................. H. elongata Takahashi, Dick & Mawatari, 2007

– Proximal constriction of the proboscis as a very short stalk or no stalk at all ................................ 18

18. Femur dorsal surface smooth except for short setae, tibia 1 about 1.2 × as long as femur ................ ................................................................................................................. H. chitinosa ( Hilton, 1943)

– Femur dorsal surface ornamented with conical tubercles, height of the tallest about half of femur diameter; tibia 1 about 1.6 × as long as femur .................................................. H. nosferatu sp. nov.