Download PDF as one large file - AToL Decapoda

Genus Typton Costa, 1844
Key to species
[Adapted from Chace, 1972]
Family Palaemonidae 161
1. Telson with posterior pair of dorsal spines arising anterior to midpoint of segment;
exopod of uropod with outer margin serrate in distal portion ......... T. prionurus
Telson with posterior pair of dorsal spines arising at, or posterior to, midpoint of
segment; exopod of uropod with outer margin entire, not serrate distally 2
2. (1) Antennal spine broad, toothlike in lateral view, not spiniform; both second
pereopods with movable fingers highly arched, nearly semicircular; major second
pereopod with carpus crenulate on proximal portion of angulate margin T. tortugae
Antennal spine strong, spiniform; second pereopods with movable fingers only
moderately convex, not nearly semicircular; major second pereopod with carpus not
crenulate on angulate margin 3
3. (2) Anterior margin of carapace produced anteriorly to level of tip of antennal spine;
exopod of uropod with outer margin rather regularly convex throughout 4
Anterior margin of carapace less produced, not nearly reaching level of tip of
antennal spine; exopod of uropod with outer margin nearly straight in distal half.. 5
4. (3) Rostrum deepest near midlength, ventral margin forming obtuse angle in lateral
view; mandible with well-developed incisor process; third pereopod with dactylus
bearing small accessory tooth on inferior margin, not clearly symmetrically bifid ....
T. carneus
Rostrum not deepening near midlength, ventral margin straight or convex; mandible
without incisor process; third pereopod with datylus bearing large accessory tooth
on inferior margin, nearly symmetrically bifid T. gnathophylloides
5. (3) Mandible with incisor process well developed and distally crenulate, molar process
tapering distally; major second pereopod with movable finger bluntly hammershaped,
not noticeably twisted T. vulcan us
Mandible with incisor process reduced to low angulate unarmed lobe, molar
process not tapering distally; major second pereopod with movable finger forming
pointed hook twisted into plane nearly perpendicular to that of palm
T. distin ctus