Sepiolinae, Leach, 1817

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 : 43-44

Dichotomous identification key to the genera of Sepiolinae

In the following key, characters valid for both sexes were used whenever possible (Atl. = Atlantic; Med. = Mediterranean).

1. Four or more longitudinal rows of suckers on regular arms ............................................................... ......................................................................................... Euprymna Steenstrup, 1887 (Indo-Pacific)

– Two longitudinal rows of suckers on regular arms (in a few species the ventral arm tips may bear more than two rows) ......................................................................................................................... 2

2. No light organ in mantle cavity. ....................................................................................................... 3 – Visceral light organs embedded in ink sac ........................................................................................ 4

3. Twelve or more longitudinal rows of suckers on tentacle clubs. Copulatory apparatus of hectocotylus a transverse crest formed by four modified sucker pedicels, with ventral hook. Female bursa copulatrix ear-like (open type) ............................................... Sepietta Naef, 1912 (NE Atl. to Med.)

– Eight to ten longitudinal rows of suckers on tentacle clubs. Copulatory apparatus of hectocotylus wide, ear-shaped, formed by many more than four modified sucker pedicels, dorsal and three proximo-ventral ones joined by web. Female bursa copulatrix pouch-like (closed type) ...................................................................................... Inioteuthis Verrill, 1818 (Indo-Pacific)

4. Paired visceral light organs, kidney-shaped ..................................................................................... 5 – Visceral light organ roundish ............................................................................................................ 8

5. Fins much longer than 50% mantle length, anteriorly almost reaching mantle margin. Distal part of hectocotylus with sucker pedicels leaf-like, latero-laterally wide ...................................................... ....................................................................................................... Lusepiola gen. nov. (Indo-Pacific)

– Fins about 50% mantle length. Sucker pedicels in distal part of hectocotylus different from above, either regular or columnar ................................................................................................................ 6

6. Hectocotylus with only one modified ventral sucker pedicel, papilla-like, in copulatory apparatus, distalmost part palisaded; female bursa copulatrix pouch-like (closed type) ..................................... ..................................................................................................... Eumandya gen. nov. (Indo-Pacific)

– Hectocotylus with four or more modified sucker pedicels, both dorsal and ventral, in copulatory apparatus and distal part with regular pedicels, a few suckers may be enlarged; female bursa copulatrix ear-like (open type) .......................................................................................................... 7

7. Ventral mantle margin slightly sinuate; copulatory apparatus of the hectocotylus a high transverse crest formed by two dorsal and two modified sucker pedicels, elongated to about the same length and fused with each other throughout their length (additional poorly developed mesial pedicels may occur in a few species) .......................................................... Sepiola Leach, 1817 (NE Atl. to Med.)

– Ventral mantle margin markedly sinuate with deep funnel indentation, protruding anteriorly on each side of funnel; copulatory apparatus of the hectocotylus with two modified ventral pedicels separate from dorsal ones, the dorsal-most ones mesially protruding towards the right arm I ........................ .............................................................................................. Adinaefiola gen. nov. (NE Atl. to Med.)

8. Visceral light organ shape approximatively round; 16 longitudinal rows of suckers on tentacle clubs; copulatory apparatus of the hectocotylus formed by two dorsal and two ventral modified sucker pedicels fused into transverse low crest, ventral-most pedicel a strong hook ................................................. Rondeletiola Naef, 1921 (Med., NE Atl. to SW Indian Ocean)

– Visceral light organ cordiform with two anterior lobes; 8 longitudinal rows of suckers on tentacle clubs; copulatory apparatus of the hectocotylus formed by three ventral modified sucker pedicels, horn-like:..................................................................................... Boletzkyola gen. nov. (West Africa)