SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 543 ...

NUMBER 543 67
Major 2nd chela with movable finger armed with subtriangular tooth on opposable
margin, not distinctly overreaching fixed finger, minor 2nd chela with fingers
densely tuberculate on opposable margins Orthopontonia
(Tanzania and Great Barrier Reef, Australia;
associated with sponge Jaspis)
35. Rostrum unarmed ventrally Pliopontonia
Rostrum with 1 or more ventral teeth, sometimes very small 36
36. Antennal scale with distolateral tooth not reaching level of distal margin of blade
Vir
Antennal scale with distolateral tooth reaching to or beyond level of distal margin
of blade 37
37. Third pereopod with dactyl armed with series of sharp teeth on flexor margin
Diapontonia
(Bahamas, western Atlantic; 244-309 meters,
associated with echinoid)
Third pereopod with dactyl simple, flexor margin unarmed 38
38. Mandible with small palp Eupontonia
(Seychelle Islands; reef flat)
Mandible without palp *PhUarius
39. Second pereopods similar though unequal, chelae strongly compressed, borne in
vertical plane with movable finger ventrad Isopontonia
(Chesterfield Islands; 15 m)
Second pereopods dissimilar and unequal, chelae subcylindrical, not strongly
compressed, borne in horizontal plane with movable finger laterad 40
40. Rostrum not T-shaped, lateral carina feebly developed; eyes small, slender, in
obsolescent orbits; 3rd pereopod with flexor margin of dactyl multidentate
Amphipontonia
(New Caledonia; 300 m, associated with
antipatharians and/or ascidians)
Rostrum T-shaped in section, with broad lateral carina; eyes large, in deep orbits;
3rd pereopod with dactyl simply biunguiculate Pontoniopsis
41. First pereopod with fingers narrowly spatulate, about as long as palm; 2nd pereopod
with fingers not spatulate, palm more than 1V2 times as long as deep; 3rd pereopod
with dactyl subconical and feebly armed Onycocaridella
First pereopod with fingers not spatulate, less than '/2 as long as palm; 2nd pereopod
with fingers subspatulate, palm less than 1 '/2 times as long as deep; 3rd pereopod
with dactyl strongly compressed and elaborately denticulate .... Onycocaris
42. Lateral branch of uropod with several movable spines at diaeresis 43
Lateral branch of uropod with single lateral movable spine 44
43. Second pereopods similar and subequal, without molar process or opposing socket
on fingers Apopontonia
(Madagascar, Australia, New Caledonia)
Second pereopods subequal but dissimilar, major chela with molar process on fixed
finger opposing socket on dactyl Paraclimenaeus
(Tanzania and Seychelle and Maldive islands;
36-91 m, associated with sponges)
44. Rostrum overreaching anteriorly extended eyes 45
Rostrum not overreaching anteriorly extended eyes 50
45. Antennal scale with distolateral tooth far overreaching distal margin of blade; 3rd
pereopod with large, compressed, angulate protuberance on flexor margin of
dactyl 46
Antennal scale with distolateral tooth not overreaching distal margin of blade; 3rd
pereopod with flexor margin of dactyl slightly convex, at most spinose, in
proximal x li of length 47