Species New to Science's Journal

[Mollusca • 2025] Flapjack Octopods of Australia (Cephalopoda: Cirrata: Opisthoteuthidae), Part II northwestern Australia and adjacent waters: Opisthoteuthis carnarvonensis & Insigniteuthis extensa comb. nov.

Opisthoteuthis carnarvonensis

Verhoeff, 2025

DOI: doi.org/10.54102/ajt.c46g9

Abstract

Herein the flapjack octopods (Opisthoteuthidae) of northwestern Australia in addition to adjacent Indonesian waters are examined. Three species are identified, all distinct from taxa recorded off southern and southeastern Australia in the preceding Part I contribution. A new species in genus Opisthoteuthis, O. carnarvonensis sp. nov., is described from five specimens collected off northwestern Australia. Opisthoteuthis cf. philipii is described from off northwestern Australia (single specimen) and Indonesian waters (seven specimens). Lastly, a partial re-description is provided for O. extensa, which is transferred to genus Insigniteuthis (comb. nov.) and has its range extended to Java and northwestern Australia, the male of I. extensa is shown to be comparable to I. dongshaensis in enlarged sucker configuration. A key is proposed to enable the identification of Opisthoteuthidae globally.

Opisthoteuthis carnarvonensis sp. nov.

Diagnosis: Opisthoteuthid with 70–78 suckers per arm of adult, a DESF of 6–10 enlarged suckers on all arms of males, located between the ~28–38th sucker, DESF sucker ⌀ < PESF sucker ⌀, and arms with web nodules; with dark brown−red aboral pigmentation and areolar spots on head and along arms. Internally with digestive gland bilobed, 7 or 8 lamellae per gill, AGC2 and 3 combined only half AG1 greatest dimensions, and with intestine approximately equal to oesophagus in length.

Etymology: Specific epithet ‘carnarvonensis’ is in reference to the Carnarvon Canyon Marine Park, from where the type material was collected, the Latin adjectival suffix ‘-ensis’ (=originating in) added to form an adjective.

Tristan Joseph Verhoeff. 2025. Flapjack Octopods of Australia (Cephalopoda: Cirrata: Opisthoteuthidae), Part II northwestern Australia and adjacent waters. Australian Journal of Taxonomy. 92: 1–28. DOI: doi.org/10.54102/ajt.c46g9 [13/5/2025]