Onychoteuthis aequimanus Gabb, 1868

Introduction

Gabb (1868) described Onychoteuthis aequimanus from two specimens collected near the Society Islands.  Although it was synonymized with Os. banksii by Adam (1962) and Voss (1962), several subsequent authors have recognized the existence of multiple banksii-affiliated species in the Pacific (Young & Harman 1987, Bolstad 2008).  Examination of the syntypes suggests that Os. aequimanus is the correct name for one of these Pacific species.  

Characteristics

1. Photophores
   1. Two circular intestinal photophores present. Anterior photophore ~40-60% diameter of posterior photophore.
   2. Ocular photophore a long whitish patch on ventral surface of each eyeball.
   
   
2. Measurements of larger syntype
   1. Mantle length - 93 mm
   2. Arm lengths - 37-50 mm
   3. Fin length - 49 mm
   4. Fin width - 56 mm (damaged)
   5. Club length - 24 mm (right)
   6. Club hook numbers - 23
      
   7. Largest hooks - Hooks V6 and V7
   8. Smallest mid-series dorsal hooks - Hooks D4 and D5
   
   
3. Tentacle club
   1. Length ~28% ML, with 20–23 hooks.
   2. Distal-most ventral hook bases not produced into spike below ML ~90 mm; may develop small spike at greater MLs.
      
      

      Click on an image to view larger version & data in a new window

      

      Click on an image to view larger version & data in a new window

      
      

      ©

   Comments

   Gabb (1868) remarked that the Os. aequimanus syntypes (two males, ANSP 6444) had been long preserved in alcohol before he received them, and had lost much pigmentation. Their soft tissues have also hardened, the tentacles appear stretched, and the hooks somewhat desiccated.  However, most of the important characters (photophores, club morphology overall body proportions, beak and radula) are in reasonable condition.
   

Distribution

References

Adam, W. 1962. C?phalopodes de l?Archipel du Cap?Vert, de l?Angola et du Mozambique. Mem?rias da Junta de Investicac?es do Ultramar, second series, 33: 9?64, pl. 1.

Bolstad, K.S. 2008. Two new species and a review of the squid genus Onychoteuthis Lichtenstein, 1818 (Oegopsida: Onychoteuthidae) from the Pacific Ocean. Bulletin of Marine Science, 83: 481?529.

Bolstad, K.S.R. 2010. Systematics of the Onychoteuthidae Gray, 1847 (Cephalopoda: Oegopsida). Zootaxa, 2696: 186 pp.

Gabb, W.M. 1868. Description of a new species of cephalopod from the South Pacific. American Journal of Conchology, 4: 23?24, 1 pl.

Voss, G.L. 1962. List of the types and species of cephalopods in the collections of the Academy of Natural Sciences of Philadelphia. Notulae Naturae, 356: 1?7.

Young, R.E. & Harman, R.F. 1987. Descriptions of the larvae of three species of the Onychoteuthis banksii complex from Hawaiian waters. The Veliger, 29: 313?321.