Streptocephalus

Rogers, D. Christopher & Padhye, Sameer, 2014, A new species of Streptocephalus (Crustacea: Anostraca: Streptocephalidae) from the Western Ghats, India, with a key to the Asian species, Zootaxa 3802 (1), pp. 75-84 : 82-83

Key to the Asian Streptocephalus

1 Females with tetrahedral eggs........................................................................... 2

1’ Females with spherical or subspherical eggs............................................................... 3

2(1) Males present; Southeast Asia............................. Streptocephalus siamensis Sanoamuang & Saengphan, 2006

2’ Males absent; Siaolanyu Island, Taiwan..................................................... Streptocephalus sp.

3(1) Male with frontal appendage branched, longer than second antenna proximal antennomere.......................... 4

3’ Male with frontal appendage lacking branches, shorter than second antennal proximal antennomere or apparently absent... 5

4(3) Antennal appendage with distal portions of both rami recurved and directed posteriorly; abdominal segments and cercopods lacking spines; Ethiopia, Arabia, Yemen.................................... Streptocephalus neumanni Thiele, 1904

4’ Antennal appendage with distal portions of both rami bent anteriorly; abdominal segments with long, paired spines; male cercopods with plumose setae on proximal half, large dorsal spines on distal half; India, Sri Lanka............................................................................................... Streptocephalus spinifer Gurney, 1906

5(3) Antennal appendage posterior ramus (“finger”) longer than anterior ramus (“thumb”) and bearing a sickle shaped lateral subramus (“lower finger”).................................................................................. 6

5’ Antennal appendage posterior ramus (“finger”) shorter than anterior ramus (“thumb”) and lacking a sickle shaped lateral subramus; Mediterranean Basin, Germany, Arabia, Yemen, through the Ponto-Caspian Region................................................................................. Streptocephalus torvicornis (Waga, 1842) Species complex

6(5) Antennal appendage posterior ramus (“finger”) with lateral sickle shaped lateral subramus inerm on proximal half, crenulate on distal half........................................................................................ 7

6’ Antennal appendage posterior ramus with lateral sickle shaped lateral subramus with a longitudinal row of spines, at least proximally with crenulations (immatures); India................................ Streptocephalus echinus Bond, 1934

7(6) Antennal appendage posterior ramus (“finger”) with longitudinal spine row distal most spine subequal in length to previous spines.............................................................................................. 8

7’ Antennal appendage posterior ramus (“finger”) with longitudinal spine row distal most spine two or more times longer than previous spines...................................................................................... 9

8(7) Antennal appendage anterior ramus (“thumb”) with an anterior, rounded projection, length, subequal to width, slightly distad of the posterior branch (“spur”); Arabia, India, Pakistan......................... Streptocephalus simplex Gurney, 1906

8’ Antennal appendage anterior ramus without an anterior projection, anterior surface of ramus smooth; India................................................................................... Streptocephalus longimanus Bond, 1934

9(7) Antennal appendage posterior ramus (“finger”) with major spines of the longitudinal spine row not tumid basally........ 10

9’ Antennal appendage posterior ramus (“finger”) with major spines of the longitudinal spine row tumid basally and aciculate distally; India........................................................... Streptocephalus sahyadriensis sp. nov.

10(9) Second antenna distal antennomere with a subtending fleshy protuberance (“wart”); Cambodia, Laos, Thailand.................................................................... Streptocephalus sirindhornae Sanoamuang et al. 2000

10’ Second antenna distal antennomere lacking a subtending fleshy protuberance; India, Myanmar, Pakistan..................................................................................... Streptocephalus dichotomus Baird, 1860