Axianassa Schmitt, 1924

Anker, Arthur & Pachelle, Paulo P. G., 2016, Mud-shrimps of the genus Axianassa Schmitt, 1924 from Panama, with description of two new species (Decapoda: Gebiidea: Laomediidae), Zootaxa 4111 (2), pp. 101-125 : 122-123

Key to the presently known species of Axianassa Schmitt, 1924

1A. Uropodal exopod with dentate diaeresis (transverse suture); rostrum with teeth on lateral margin....................... 2

1B. Uropodal exopod without diaeresis (transverse suture); rostrum without teeth on lateral margin........................ 3

2A. Carapace with two pairs of short longitudinal carinae anterodorsally; first pleuron terminating in blunt process ventrally........................................................................... A. japonica [W Pacific: Japan, 15 m]

2B. Carapace without longitudinal carinae anterodorsally; first pleuron produced into strong spiniform process ventrally........................................................ A. heardi [W Pacific: Australia and French Polynesia, 0.5–1 m]

3A. Antennal acicle not overreaching third article of antennal peduncle, bifid (with two strong teeth distally); dactylus of third and fourth pereiopods with multiple rows of stout spiniform setae extending along entire length of dactylus; third maxilliped carpus with strong ventral tooth............................ A. mineri [E Pacific: Panama, Costa Rica, Mexico, intertidal]

3B. Antennal acicle overreaching third article of antennal peduncle, ending in single acute point; dactylus of third and fourth pereiopods with only one row of stout spiniform setae extending along full length of dactylus; third maxilliped carpus unarmed.................................................................................................... 4

4A. Major cheliped ischium unarmed, at most finely denticulate, on ventral margin; third maxilliped merus with rows of thick fusiform (villiform) setae on ventral surface.................................................................... 5

4B. Major cheliped ischium armed with at least two strong sharp teeth on ventral margin; third maxilliped merus without fusiform (villiform) setae on ventral surface........................................................................ 6

5A. Cheliped merus strongly serrated distally; major cheliped finger less than 0.5 length of palm; crista dentata of third maxilliped with all teeth relatively small......................... A. intermedia [W Atlantic: Puerto Rico and Curação, intertidal]

5B. Cheliped merus unarmed, at most finely denticulate (with minute widely spaced denticles); major cheliped fingers 0.6–0.7 length of palm; crista dentata of third maxilliped with several conspicuously larger teeth among smaller teeth........................................................................... A. linda sp. nov. [E Pacific: Panama, intertidal]

6A. Antennal acicle with mesial tooth......................................................................... 7

6B. Antennal acicle without mesial tooth..................................................................... 10

7A. First pleuron with strong spiniform process ventrally, in both sexes.............................................. 8

7B. First pleuron rounded ventrally, in both sexes.... A. jamaicensis [W Atlantic: Jamaica and Panama, intertidal to about 2 m]

8A. Third maxilliped ischium with rows of thick villiform (fusiform) setae on ventral surface; cheliped merus with strong tooth on ventral margin............................................. A. canalis [E Pacific: Panama, intertidal to about 2 m]

8B. Third maxilliped ischium without thick setae ventrally; cheliped merus without strong tooth on ventral margin, at most finely denticulate........................................................................................... 9

9A. Antennal acicle reaching 0.35 length of fourth article of antennal peduncle; third to fifth pleura with moderate pubescence, not obscuring pleural margins; third maxilliped coxa usually with two small teeth on dorsomesial surface, occasionally with one tooth........................................ A. darrylfelderi [E Pacific: Colombia and Panama, intertidal to 0.5 m]

9B. Antennal acicle barely reaching 0.25 length of fourth article of antennal peduncle; third to fifth pleura with strong pubescence, usually obscuring pleural margins; third maxilliped coxa with one large tooth on dorsomesial surface........................................................... A. australis [W Atlantic: Gulf of Mexico, Florida, Brazil, intertidal to 0.5 m]

10A. Second to fifth pleura each armed with acute tooth ventrally........... A. arenaria [W Atlantic: Gulf of Mexico, 34–38 m]

10B. Second to fifth pleura unarmed ventrally.................................................................. 11

11A. Rostrum broadly rounded; cheliped merus finely denticulate, without enlarged teeth............................................................................................ A. ngochoae [W Pacific: French Polynesia, 0.5–1 m]

11B. Rostrum pointed distally; cheliped merus finely denticulate with one noticeably larger tooth, or smooth with one very stout tooth............................................................................................... 12

12A. Rostrum reaching far beyond eyestalks; pleuron of first pleuron produced into spiniform process ventrally; third article of antennular peduncle with small mesial tooth; cheliped merus with conspicuous subdistal tooth............................................................................................... A. sinica [W Pacific: China, 33–42 m]

12B. Rostrum not overreaching eyestalks; pleuron of first pleuron unarmed ventrally; third article of antennular peduncle without mesial tooth; cheliped merus with relatively small tooth at about mid-length............................................................................................. A. christyi sp. nov. [E Pacific: Panama, intertidal to 0.5 m]