This tree diagram shows the relationships between several groups of organisms.
The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.
You can click on the root to travel down the Tree of Life all the way to the root of all Life, and you can click on the names of descendent subgroups to travel up the Tree of Life all the way to individual species.close box
Members of the Rossinae are among the larger sepiolids reaching up to 10 cm ML (Reid, 1991). They are benthic and mostly occupy the outer portions of the continental shelves and upper regions of the slope. The subfamily nearly has a world wide distribution (see below) along parts of major land masses but is not know from Antarctic waters.
A sepiolid ...
- with dorsal mantle free from head.
- without ventral mantle shield.
- Interbrachial web weakly developed between arms I-III.
- Non-hectocotylized arm suckers in 2 series in most species but 4 series in at least two species.
- One or both dorsal arms of male hectocotylized; often with suckers in two or four series among other modifications.
- Tentacular clubs usually expanded.
- Keel along full length of club. image info
Figure. Oral view of the tentacular club of Rossia pacifica, preserved. Photograph by R. Young.
- Mantle free from head in nuchal region; nuchal cartilage present. image info
Figure. Dorsal view of the mantle and head of Rossia macrosoma with anterior portion of mantle folded back to reveal the nuchal cartilage (blue) and anterior end of the gladius (red). Drawing modified from Naef (1921-23).
- Gladius fully-developed but thin posteriorly.
- Bursa copulatrix absent.
- Photohores, when present, with with small, separate oval lenses.
The following table compares the four genera.
|Arms II, III with greatly enlarged suckers||Clubs expanded||Club sucker series||Photophores present on ink sac||Functional Ink sac||Anal flaps|
Austrorossia is often considered a subgenus of Rossia (Voss, 1956; Reid, 1991). We follow the classification of Nesis (1982/87).
Figure. Distribution map of the Rossiinae (white lines). Distributions are approximate. Modified from Young, et al. (1998).
Reid, A. 1991. Taxonomic Review of the Australian Rossiinae (Cephalopoda: Sepiolidae), with a Description of a New Species, Neorossia leptodons, and Redescription of N. caroli (Joubin, 1902) . Bulletin of Marine Science, 49(3)(1991):748-831.
Young, R. E., M. Vecchione and D. Donovan. 1998. The evolution of coleoid cephalopods and their present biodiversity and ecology. South African Jour. Mar. Sci., 20: 393-420.
Voss, G.L. 1956. A Review of the Cephalopods of the Gulf of Mexico. Bulletin of Marine Science of the Gulf and Caribbean, 6(2):85-178.