Family PHOLIDOTEUTHIDAE Adam, 1950

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• PHOLIDOTEUTHIDAE Adam, W. 1950. Un cephalopode nouveau: Pholidoteuthis boschmai gen. et sp. nov. Proceedings of the Koninklijke Nederlandse Akademie Wetenschappen 53: 1592-1598.

  Type genus:

   Pholidoteuthis Adam, 1950.

 

Introduction

The family Pholidoteuthidae was considered to includes two genera, Pholidoteuthis and Tetronychoteuthis, of medium- to large-sized (up to 1000 mm mantle length (ML)) oceanic and continental slope species (Roper et al. 1969). However, the status of these genera is uncertain. Nesis & Nikitina (1990) considered Tetronychoteuthis to be a nomen dubium. Roper & Lu (1989, 1990) also pointed out the confusion concerning validity of various names associated with these squids. A case needs to be referred to the International Commission on Zoological Nomenclature, and the taxonomy of this group requires revision. Clarke (1966) suggested that the two currently recognised species in the genus Tetronychoteuthis may be growth stages of Pholidoteuthis boschmai Adam. The genus Tetronychoteuthis is retained in Lu (2001).

A single specimen of Tetronychoteuthis dussumieri was described by Pfeffer (1912) from south of Western Australia. Allan (1945) assigned juvenile specimens caught in plankton nets off New South Wales to Tetronychoteuthis massyae Pfeffer, a species which Pfeffer (1912) considered might represent a juvenile form of T. dussumieri. Rancurel (1970, 1976) reported both T. massyae and Lepidoteuthis grimaldii Joubin, 1895 from the stomachs of lancetfish (Alepisaurus) caught in the Coral Sea, and Clarke (1980) and Clarke & MacLeod (1982) found lepidoteuthids among the stomach contents of sperm whales from south-western Australia and the Tasman Sea, respectively.

The family is easily recocognised by the presence of 'scales' or tubercles. On Pholidoteuthis adami, these 'scales' (called 'dermal cushions' by Roper & Lu (1990)) are irregularly rounded to roughly pentagonal in outline. Internally, they consist of very dense material interspersed with numerous small vacuoles which are thin walled chambers of irregular size and shape. The tubercles in Tetronychoteuthis massyae are stellate, minute and tightly packed. Each tubercle is roundly mushroom shaped in profile, with a slightly concave central disc and a thick base. Roper & Lu (1990) suggested that the dermal cushions, like those on Lepidoteuthis grimaldi, may serve to store less dense solution containing ammonium ions, and, together with the mantle, function as a buoyancy mechanism. The tubercles on Tetronychoteuthis massyae are thought to maintain laminar flow along the boundary layer during locomotion by reducing hydrodynamic drag.

Pholidoteuthis has been caught in demersal trawls in continental slope waters, but only during the day. It seems likely, therefore, that this species leaves the near-bottom waters and disperses into midwater at night (Roper & Young 1975). Clarke (1980) suggested that large individuals of Pholidoteuthis may be solitary or occur in small groups. In the Gulf of Mexico, schools of P. adami have been observed at the surface at night.

 

Diagnosis

Pholidoteuthids are characterised by the presence of distinct 'scales' ('dermal cushions') or tubercles on the mantle, a simple, straight funnel locking apparatus, biserial toothed suckers on the arms and tetraserial suckers on the tentacular clubs. Buccal connectives attach to the ventral border of the ventral arms and light organs are absent. Hectocotylisation in males has not been described. The dermal cushions in Pholidoteuthis adami are irregularly rounded to roughly pentagonal in outline. Tubercles in Tetronychoteuthis massyae are stellate, minute and tightly packed. Each tubercle is roundly mushroom-shaped in profile, with a slightly concave central disc and a thick base.

 

General References

Allan, J. 1945. Planktonic cephalopod larvae from the eastern Australian coast. Records of the Australian Museum 21: 317-350 pls 24-27

Clarke, M.R. 1966. A review of the systematics and ecology of oceanic squids. Advances in Marine Biology 4: 91-300

Clarke, M.R. 1980. Cephalopoda in the diet of sperm whales of the southern hemisphere and their bearing on sperm whale ecology. Discovery Reports 37: 1-324

Clarke, M.R. & MacLeod, N. 1982. Cephalopod remains from the stomachs of sperm whales caught in the Tasman Sea. Memoirs of the National Museum of Victoria, Melbourne 43: 25-42

Lu, C.C. 2001. Cephalopoda. pp. 129-308 in Wells, A. & Houston, W.W.K. (eds). Zoological Catalogue of Australia. Vol. 17.2 Mollusca: Aplacophora, Polyplacophora, Scaphopoda, Cephalopoda. Melbourne : CSIRO Publishing, Australia xii 353 pp. [Date published 3 July 2001]

Nesis, K.N. & Nikitina, I.V. 1989. Revision of the squid family Lepidoteuthidae. Zoologicheskii Zhurnal 69: 39-49

Pfeffer, G. 1912. Die Cephalopoden der Plankton-Expedition. Zugleich eine monographische Ubersicht der Oegopsiden Cephalopoden. Ergebnisse der Plankton-Expedition der Humboldt-Stiftung 2: 1-815 pls 1-48

Rancurel, P. 1970. Les contenus stomacaux d'Alepisaurus ferox dans le sud-ouest Pacifique (Céphalopodes). Cahiers O.R.S.T.O.M. Serie Océanographique 8(4): 4-87

Rancurel, P. 1976. Note sur les Céphalopodes des contenus stomacaux de Thunnus albacares (Bonnaterre) dans le Sud-ouest Pacifique. Cahiers O.R.S.T.O.M. Serie Océanographique 14(1): 71-80

Roper, C.F.E., Young, R.E. & Voss, G.L. 1969. An illustrated key to the families of the order Teuthoidea (Cephalopoda). Smithsonian Contributions to Zoology No. 13: 1-32

Roper, C.F.E. & Lu, C.C. 1989. Systematics status of Lepidoteuthis, Pholidoteuthis, and Tetronychoteuthis (Cephalopoda: Oegopsida). Proceedings of the Biological Society of Washington 102(3): 805-807

Roper, C.F.E. & Lu, C.C. 1990. Comparative morphology and function of dermal structures in oceanic squids (Cephalopoda). Smithsonian Contributions to Zoology No. 493: 1-40

Roper, C.F.E. & Young, R.E. 1975. Vertical distribution of pelagic cephalopods. Smithsonian Contributions to Zoology No. 209: 1-51

 

History of changes

Published	As part of group	Action Date	Action Type	Compiler(s)
05-Jun-2024	CEPHALOPODA Cuvier, 1795	29-May-2023	MODIFIED	Dr Mandy Reid
20-Mar-2014	TEUTHIDA	20-Mar-2014	MODIFIED	Dr Julian Finn (NMV)
		12-Feb-2010	(import)