Parathelphusa, H. Milne Edwards, 1853

Ng, Oliver K. S. Chia Peter K. L., 2006, The Freshwater Crabs Of Sulawesi, With Descriptions Of Two New Genera And Four New Species (Crustacea: Decapoda: Brachyura: Parathelphusidae), Raffles Bulletin of Zoology 54 (2), pp. 381-428 : 382-384

Key to the species of Parathelphusa and allied genera of Sulawesi

1a. Anterolateral margin of carapace with two or more visible teeth, teeth occasionally very low but always discernible at least as low lobes .............................. 2

1b. Anterolateral margin of carapace with only one visible tooth (occasionally almost undiscernible) .................. ................................. 18 ( Sundathelphusa ) (pg. 418)

2a. Carapace squarish. Frontal margin with well developed deeply recessed median triangle. Chela and fingers slender, outer surfaces not prominently convex. Propodus of last pair of ambulatory legs broad. Third pair of ambulatory meri longest .................................. ................................. 3 ( Nautilothelphusa ) (pg. 412)

2b. Carapace narrowly to broadly transverse. Frontal margin with well developed median triangle which is relatively level with rest of frontal margin. Chela and fingers stout, outer surfaces convex. Propodus of last pair of ambulatory legs narrow. Second pair of ambulatory meri longest .......................................... 4

3a. Epigastric cristae weak. Frontal margin sinuous. External orbital angle acutely triangular, extends beyond frontal margin. First and second epibranchial teeth sharp, distinct, acutely triangular. Ambulatory meri armed with sharp subterminal spine. G1 stout, truncate ............. Nautilothelphusa zimmeri (pg. 413)

3b. Epigastric cristae strong, sharp. Frontal margin relatively straight. External orbital angle triangular, does not extend beyond frontal margin. First and second epibranchial teeth blunt, low, acutely triangular. Ambulatory meri unarmed. G1 slender, relatively long ..................................................................................... Migmathelphusa olivacea , new genus, new species (pg. 416)

4a. Carapace dorsal surface rugose. Epigastric and postorbital cristae distinct, rugose but not sharp. Posterior margin of epistome continuous, without distinct clefts or fissures. Third maxilliped merus with notch or deep depression on the anterior margin. Cheliped fingers with pair of large opposable molarifrom teeth, even in small specimens. Dorsal subterminal spine on ambulatory merus strong, sharp ........................... 5 ( Syntripsa , new genus) (pg. 408)

4b. Carapace dorsal surface smooth. Epigastric and postorbital cristae strong and sharp. Posterior margin of epistome not continuous, antero-lateral margin of epistome recessed. Third maxilliped merus with anterior margin flushed. Cheliped fingers with small teeth, not molariform. Dorsal subterminal spine on ambulatory merus small and sharp or absent ................................. ...................................... 6 ( Parathelphusa ) (pg. 384)

5a. Carapace with red spots on olive-green background when alive or freshly preserved. Chela cream coloured, fingers pigmented black. Eye-stalk cream-coloured. Joints of ambulatory legs not pigmented. Distinct cervical groove. Distinct H-shaped depression. Postorbital cristae do not reach anterolateral margin, stopping just before base of first epibranchial tooth. Male abdomen stops at median point between anterior and posterior edges of the cheliped bases. G1 stout, straight with straight outer margin without a cleft on proximal part ............................................................... Syntripsa flavichela , new genus, new species (pg. 410)

5b. Carapace a uniform deep reddish purple when alive or freshly preserved. Chela reddish-purple, fingers pigmented black. Eye-stalk white coloured. Joints of ambulatory legs pigmented white. Shallow cervical groove. Shallow H-shaped depression. Postorbital cristae reach anterolateral margin, touching base of first epibranchial tooth. Male abdomen reaches imaginary line joining anterior edges of chelipeds bases. G1 relatively slender, gently curving outwards, with a slightly sinuous outer margin, proximal part slightly clefted ................... Syntripsa matannensis (pg. 409)

6a. Anterolateral teeth well demarcated, usually prominent, triangular .................................................................. 7

6b. Anterolateral teeth not well demarcated, very low to almost confluent with each other ........................... 10

7a. External orbital angle triangular. First and second epibranchial teeth triangular to acutely triangular ... 8

7b. External orbital angle triangular to broadly triangular. First epibranchial tooth blunt and low or almost confluent with external orbital angle. Second epibranchial teeth blunt and low but distinct .......... 9

8a. Carapace rusty-red in life or freshly preserved. Dorsal surface of carapace prominently rugose and finely granulose. Postorbital cristae does not reach anterolateral margin, stopping before beginning of cervical groove ............................................................ ... Parathelphusa ferruginea , new species (pg. 406)

8b. Carapace, cheliped and ambulatory legs spotted with distinct rosette pattern when alive or freshly preserved. Dorsal surface of carapace slightly rugose, appearing mostly smooth. Postorbital cristae reaches the base of the first epibranchial tooth .......................................... ........................ Parathelphusa pantherina (pg. 385)

9a. Anterolateral regions smooth. Postorbital cristae end well before anterolateral margin. First and second epibranchial teeth well demarcated but blunt, with distinct notch between external orbital angle and first epibranchial tooth and between first and second epibranchial teeth. Ambulatory merus smooth throughout, no trace of dorsal subterminal angle or spine. Colour in life dark yellow to yellowish-green, in preservative deep olive-green ................................ ..................... Parathelphusa sarasinorum (pg. 387)

9b. Anterolateral regions with strong striae. Postorbital cristae end at base of second anterolateral tooth. First epibranchial tooth low, weakly demarcated from external orbital tooth, may be almost confluent with it, second epibranchial tooth low, blunt, relatively broad. Ambulatory merus with dorsal subterminal angle, not spiniform but may be relatively sharp. Colour in preservative yellowish brown ................................ ........................... Parathelphusa lokaensis (pg. 389)

10a. Cleft present on postorbital cristae where cervical groove begins. Upper margin of frontal median triangle separated from lateral margins by distinct gap. G1 proximal outer margin with distinct, broad, deep Vshaped cleft ....... Parathelphusa ceophallus (pg. 391)

10b. Postorbital cristae more or less continuous. Upper and lateral margins of frontal median triangle fused, confluent or upper margins not discernible, absent. G1 proximal outer margin with shallow cleft or appearing almost entire ........................................................... 11

11a. Epibranchial teeth low but discernible .................. 12

11b. Epibranchial teeth almost confluent with rest of anterolateral margin ............................................... 13

12a. Postorbital cristae ends at base of second epibranchial tooth, epibranchial teeth relatively distinct ................ .......................... Parathelphusa celebensis (pg. 393)

12b. Postorbital cristae ends between base of first and second epibranchial teeth, epibranchial teeth low, knob-like. ............................ Parathelphusa tenuipes (pg. 397)

13a. Branchial regions highly inflated, swollen. Anterolateral margin diverges sharply after external orbital angle. Cornea of eye reduced. G1 relatively long, slender ................................................................ .......... Parathelphusa sorella , new species (pg. 403)

13b. Branchial regions gently convex, not prominently inflated. Anterolateral margin diverges gently after external orbital angle. Cornea of eye not reduced. G1 relatively short, stout or slender ............................ 14

14a. Dactylus of ambulatory leg relatively long, slender. Fingers longer then palm of cheliped ........................ ..................... Parathelphusa pareparensis (pg. 399)

14b. Dactylus of ambulatory leg relatively short, broad. Fingers shorter than or subequal to palm of cheliped ................................................................................ 15

15a. Dorsal margin of frontal median triangle distinct. G1 relatively stout, stocky ................................................ ............................... Parathelphusa pallida (pg. 395)

15b. Dorsal margin of frontal median triangle weak or indistinct. G1 comparatively slender ..................... 16

16a. Post orbital cristae reach base of second epibranchial tooth. Suture between thoracic sternites 3 and 4 absent ............................... Parathelphusa crocea (pg. 402)

16b. Postorbital cristae reach base of first epibranchial tooth or stops short of anterolateral margin and ends at cervical groove. Suture between thoracic sternites 3 and 4 distinct .......................................................... 17

17a. Frontal median triangle broad, low. Postorbital cristae does not reach anterolateral margin, stopping on meeting cervical groove .............................................. ......................... Parathelphusa linduensis (pg. 403)

17b. Frontal median triangle relatively narrow, high. Postorbital cristae does not reach anterolateral margin, stopping at base of first epibranchial tooth ............... ......................... Parathelphusa possoensis (pg. 398)

18a. Anterolateral margins of adult specimens strongly convex, carapace appearing transversely ovate. G1 tip truncate ............. Sundathelphusa cassiope (pg. 418)

18b. Anterolateral margins of adult specimens gently convex, carapace appearing more squarish. G1 tip rounded to sharp ....................................................................... 19

19a. External orbital angle hardly separated from rest of anterolateral margin, margin appearing almost confluent. Branchial regions distinctly swollen, surface smooth. G1 almost straight with distal part slightly curved ................... Sundathelphusa rubra (pg. 419)

19b. External orbital angle distinctly separated from rest of anterolateral margin by a notch. Branchial regions not prominently swollen, surface lined with striae. G1 curving outwards ......................................................... .................... Sundathelphusa minahassae (pg. 419)