Acutiramus, , Harris & Robertson, 1994

Harris, Vernon A., 2014, Porcellidiidae of Australia (Harpacticoida, Copepoda). II. The Importance of the Male Antennule in Taxonomy, Records of the Australian Museum 66 (2), pp. 111-166 : 139-140

Key to the species of Acutiramus

1 No internal seta on segment 1 of P3 endopod. Animals live in association with hermit crabs .................................................................................................... 2

—— Internal seta present on segment 1 of P3 endopod. Animals live on seaweed ................................................................................................................................ 6

2 Female caudal ramus rhomboid, T2 and T3 close together, wide gap between T3 and T4 . Male shoulders rounded ............................................................ 3

—— Female caudal ramus not rhomboid, tapers posteriorly, posterior

edge rounded, no network of ridges (if present not prominent,

restricted to posterior). T2, T3 and T4 evenly spaced. Male

shoulders rounded ................................ Acutiramus tapui (Hicks & Webber, 1983) comb. nov.

—— Female caudal ramus rhomboid with conspicuous dorsal network of ridges, T2, T3 and T4 bunched together at apex. Male shoulders prominent ...................................................................... Acutiramus cumulus sp. nov.

3 1/4 or more of caudal ramus enclosed in arch of genital doublesomite ........................................................................................................................................ 4 —— Caudal ramus completely excluded from arch of genital doublesomite .................................................... Acutiramus brevicaudatus (Thompson & Scott, 1903)

4 Number of setae on internal edge of P3 endopod = 0:2:4, P4 endopod = 0:1:3 ........................................................ Acutiramus paguri (Ho, 1986) comb. nov.

—— Number of setae on internal edge of P3 endopod = 0:2:5, P4 endopod = 1:1:4 ......................................................................................................................... 5

5 Female rostrum appears concave with straight hyaline border. Male rostrum with conspicuous anterior point. γ seta on male caudal ramus equals width of ramus ............................................. Acutiramus iwasakii sp. nov.

—— Anterior border of female rostrum not concave. Male rostrum not pointed anteriorly. γ seta on male caudal ramus twice width of ramus ........................................................................ Acutiramus similis (Kim & Kim, 1996) 6 α and β setae on female caudal ramus not close (equal to or greater than 1/3 length of ramus apart). Male P5 trapezoid (sides not parallel) ............................................................................................................................... 7

—— α and β setae on female caudal ramus not close (equal to or greater than 1/3 length of ramus apart). Male P5 rhomboid (sides parallel). Male P2 endopod with two terminal setae ................................................................. Acutiramus geddesi ( Geddes, 1968) comb. nov.

—— α and β setae on female caudal ramus close together (1/8

length of ramus apart). Male P5 trapezoid. Male P2 endopod

with three terminal setae. (Plate 2A) ... Acutiramus sesquimaculatus (Harris, 1994) comb. nov.

7 Anterior bulge on female cephalosome partly obscures rostrum. Male antennule with ventral blade ............................................................................................ 8

—— No anterior bulge on cephalosome, rostrum prominent. No ventral blade on male antennule ................................................................................................ 9

8 Female P5 truncated posteriorly. Female genital doublesomite without lateral notch. Ventral blade on male antennule about 1/2 length of compound segment 3 + 4. (Plate 2B, p. 165) ..................................................................... Acutiramus rufolineatus Harris & Robertson, 1994

—— Female P5 not truncated (P5 laid flat), apex with small notch. Female genital double-somite with distinct lateral notch. Ventral blade on male antennule small (less than 1/4 length of segment 3 + 4. (Plate 2E, p. 165) ........................ Acutiramus quinquelineatus Harris & Robertson, 1994

9 Rostrum with clear spherical “lens”. Seta T1 on female caudal ramus very small, T3 very slender, space between T3 and T4 setae 2/3 length of oblique posterior edge of ramus. Coupling denticle on male antennule C-shaped, anterior lobe carrying δ seta short ............................................................................... Acutiramus bipunctatus sp. nov.

—— No spherical “lens” in rostrum. Seta T1 on female caudal ramus as large as T4, T3 same as T2, space between T3 and T4 setae 1/2 length of oblique posterior edge of ramus. Coupling denticle on male antennule not C-shaped, anterior lobe carrying δ seta long, finger-like .................................................................... Acutiramus edenensis sp. nov.