Inioteuthis Verrill, 1881

Bello, Giambattista, 2020, Evolution of the hectocotylus in Sepiolinae (Cephalopoda: Sepiolidae) and description of four new genera, European Journal of Taxonomy 655 (655), pp. 1-53 : 40

Inioteuthis Verrill, 1881

Fig. 12

Inioteuthis Verrill, 1881: 417 .

Type species

Inioteuthis japonica Verrill, 1881 , by subsequent designation.

Diagnosis

Sepiolinae with fins rounded; their length about half mantle length. Suckers biseriate on all arms. Tentacle club suckers in 8 to 10 longitudinal rows. Mantle-head occipital band narrow (not reaching over the ocular globes). Visceral photophores absent. Gladius absent. Ventral mantle margin slightly sinuate, without any deep funnel indentation. Hectocotylus (male left arm I) tripartite: basal part with three suckers, two ventral and one dorsal; copulatory apparatus broadly enlarged, ear-shaped, involving about six dorsal and seven ventral modified sucker pedicels; dorsal pedicels (may bear vestigial suckers) lengthened, rolled ventrally, joined by a broad web proximally crossing the arm oral face to reach ventral formation of three horn-like pedicels, connected with each other by narrow web, so that a webbed structure delimits meso-proximally a hollow; proximal horn-like pedicels of ventral row followed distally by a void hence by about four deeply modified pedicels combined into a trough-like formation; distal part with several enlarged suckers in ventral row, first one very large, laying on trough-like structure of copulatory apparatus. Female bursa copulatrix pouch-like.

Included species

Inioteuthis japonica Verrill, 1881 and I. maculosa Goodrich, 1896 .

Remarks

An Indo-Pacific genus that presently includes two species (see above). A third species usually listed in this genus, namely Inioteuthis capensis Voss, 1962 , in fact does not belong to it ( Young & Vecchione 2004), since according to its original description I. capensis bears a roundish light organ embedded in the ink sac, a trait that does not pertain to Inioteuthis . Hence, capensis is excluded from this genus and placed in Rondeletiola (see below).

Figures

Fig. 12. Hectocotylus of Inioteuthis japonica Verrill, 1881. A. Oral view. B. Lateral view. The brackets P and D comprise the proximal and distal structures of the copulatory apparatus ventral side, respectively; an X marks the longitudinal crest between the two structures. The curved line embraces the swollen dorsal margin of the copulatory apparatus, whose modified pedicels (indicated by arrows) look like trabeculae holding the joining web. Scale bars: 2 mm.