Periclimenaeus, Ramos-Tafur & Lemaitre, 2017

Ramos-Tafur, Gabriel E. & Lemaitre, Rafael, 2017, A new species of shrimp of the genus Periclimenaeus Borradaile, 1915 (Decapoda: Caridea: Palaemonidae) from the southeastern Gulf of Mexico, including a key to the western Atlantic species of the genus, Zootaxa 4303 (4), pp. 491-508 : 505

Key to the western Atlantic species of Periclimenaeus

1. Carapace with small postorbital spine or tubercle; rostrum armed with 1 subterminal ventral tooth; scaphocerite with distolateral tooth overreaching distal end of lamella.................................................................................................. P. caraibicus Holthuis, 1951 (Lesser Antilles, Barbados, Dominica, Belize to Brazil)

- Carapace without postorbital spine or tubercle; rostrum with or without subterminal ventral teeth; scaphocerite with distolateral tooth not overreaching distal end of lamella (absent in P. schmitti Holthuis, 1951 )...............................2

2. Male with rounded anterior median lobe on tergite of first abdominal somite, that lobe absent or weakly developed in mature females; third and fourth abdominal pleurae each with distinct anteroventral projection; minor chela fixed finger with series of long setae on either side of dactylus...................................................................... 3

- Male and female abdomen without anterior median lobe on tergite of first abdominal somite; third and fourth abdominal pleurae rounded ventrally; minor chela fixed finger without series of long setae on dactylus............................. 4

3. Rostrum armed with 2 small subdistal teeth on ventral margin; telson with both pairs of dorsal spines on anterior third................................................................. P. mcmichaeli sp. nov. (off of Dry Tortugas, Florida)

- Rostrum unarmed ventrally; telson with only first pair of dorsal spines on anterior third........................................................... P. wilsoni ( Hay, 1917) (North Carolina to Georgia; Gulf of Mexico: Louisiana and Florida)

4. Chelae of first pereopods with distal cutting edge of fingers with row of minute denticles (pectinate)............................................................................ P. pectinidactylus Ďuriš Horká & Sandford 2009 (Belize)

- First pereopods chelae with fingers furnished with setae but never with denticles...................................5

5. First pair of pereopods distinctly long and slender, with carpus nearly twice as long as chela............................................................ P. perlatus ( Boone, 1930) ( Tortugas, Haiti, Veracruz, Mexico to Panama and Brazil)

- First pair of pereopods not long and slender, carpus as long as or slightly longer than chela......................... .. 6

6. Rostrum short, tip not reaching or slightly overreaching distal margin of corneas...................................7

- Rostrum long, tip distinctly overreaching distal margin of the corneas...........................................10

7. Rostrum short, tip barely overreaching distal end of antennal spine, dorsal teeth contiguous, serrate in appearance............................................. P. pearsei ( Schmitt, 1932) (Dry Tortugas, Florida, Veracruz, Mexico, and Brazil)

- Rostrum overreaching distal margin of antennal spine, dorsal teeth evenly spaced.................................. 8

8. Scaphocerite without distolateral tooth............................. P. schmitti Holthuis, 1951 (Dry Tortugas, Florida)

- Scaphocerite with distolateral tooth.......................................................................9

9. Dactylus of third pereopod simple; rostrum with 2 dorsal teeth; first antennular segment anterolateral angle unarmed distally................................................. P. maxillulidens Schmitt, 1936 (Cape San Blas, Florida, Bonaire)

- Dactylus of third pereopod biunguiculate; rostrum with 3 dorsal teeth; first antennular segment with anterolateral angle armed with small spine.............. P. ascidiarum Holthuis, 1951 (Dry Tortugas, Florida to Cape La Vela , Colombia and Brazil)

10. Rostrum with 4 dorsal teeth; anterior pair of dorsal spines of telson on anterior half................................ 11

- Rostrum with 7 or 8 dorsal teeth; telson with anterior and posterior pair of dorsal spines on anterior third.............. 12

11. Telson with anterior pair of dorsal spines near anterior margin of segment............................................................................................... P. chacei Abele, 1971 (west off Hernando Beach, Florida)

- Telson with first pair of dorsal spines near midlength of segment............................................................................................. P. atlanticus ( Rathbun, 1901) ( Saint Thomas, Virgin Islands to Brazil)

12. Second pereopod with dactylus of major chela overreaching tip of fixed finger............................................................................................. P. crosnieri Cardoso & Young, 2007 (Rocas Atoll, Brazil)

- Second pereopod with dactylus of major chela not overreaching tip of fixed finger.................................13

13. Rostrum with 8 dorsal teeth; palm of major chela with rows of conspicuous tubercles......................................................................................... P. brucei Cardoso & Young, 2007 (Rocas Atoll, Brazil)

- Rostrum with 7–8 dorsal teeth; palm of major chela with few minute tubercles......................................................................................... P. bredini Chace, 1972 (Isla Mujeres, Quintana Roo, Mexico)