Characters | O. similis Claus, 1866 | O. nana Giesbrecht, 1892 | O. plumifera Baird, 1843 | O. atlantica Farran, 1908 | O. davisae Ferrari and Orsi, 1984 |
---|---|---|---|---|---|
Total length (mm) | 0.68–0.96 | 0.5–0.65 | 1.18–1.28 | 1.14–1.43 | 0.54–0.62 |
P:U | 1.1–1.4 | 1.0–1.2 | 1.0–1.2 | 1.1–1.3 | 1.2 |
Rostrum | Curved, short, and pointed | No | Not curved, pointed, dorsally visible | Not curved, pointed, dorsally visible | Curved, strong, and ventrally pointed |
Caudal rami L:W | 1.9–2.4 | 2.1–2.7 | 3.0–3.7 | 3.1–3.8 | 3.0 |
Mx1 Li1 distal most spine | Short | Short | Short | Short | Longer than other setae |
Mx1 End no. of setae | 1 min seta | 1 seta | 1 min seta or lacking | 1 long seta | 1 setaa |
Md B2 distal spines | 2 pointed spines | 1 long and 1 min pointed spine | 1 longer and 1 shorter pointed spine | 1 longer and 1 shorter pointed spine | 2 thick blunt curved spines |
Outer marginal spines (Exp1, Exp2, Exp3) | |||||
P1 | 1, 1, 2 | 1, 1, 3 | 1, 1, 2 | 1, 1, 2 | 1, 1, 3 |
P2 | 1, 0, 1 | 1, 1, 3 | 1, 0, 2 | 1, 0, 2 | 1, 1, 3 |
P3 | 1, 0, 1 | 1, 1, 3 | 1, 0, 1 | 1, 0, 1 | 1, 1, 3 |
P4 | 0, 0, 1 | 1, 1, 2 | 0, 0, 1 | 0, 0, 1 | 1, 1, 2 |
References | Nishida (1985) | Nishida (1985) | Nishida (1985) | Nishida (1985) | Ferrari and Orsi (1984) |