Histioteuthidae Verrill 1881

FAMILY HISTIOTEUTHIDAE VERRILL, 1881

(18 SPECIES IN TWO GENERA)

Diagnosis: Medium to large adult-sized, weakly muscled and ammoniacal Oegopsida with buccal connectives attached to the dorsal borders of ventral arms; with an asymmetrical external and internal morphology, left eye much larger than right counterpart; with two series of arm suckers; tentacles characteristic, with expanded clubs having nonuniform series of suckers, with large suckers with stalks devoid of neck constrictions, carpal locking apparatus in linear series; funnel–mantle locking apparatus straight to slightly curved, reaching the anterior margins of the mantle; ventral surfaces of the head, mantle and arms covered with compound anteriorly directed photophores with red colour filters; posterior end of the gladius with a cupped coil shape, without the atp6 copy in the duplicated gene cluster associated with nad2.

Remarks: In the phylogeny provided here, Histioteuthidae and Onychoteuthidae clustered together with poor support in the ML analysis and high support in the BI analysis. Young & Vecchione (2016a) showed that the morphology of the tentacle suckers of Histioteuthidae and Psychroteuthidae is almost identical and considered it a good taxonomic character. This last relationship also received high support in the multilocus phylogenetic work of Lindgren (2010) and Lindgren et al. (2012). We did not include any Psychroteuthidae in the analysis. We avoid any superfamily designation until the relationship between Histioteuthidae, Onychoteuthidae and Psychroteuthidae can be confirmed by future phylogenomic analyses.