Taningia danae Joubin, 1931

Introduction

This species reaches a maximum of 170 cm ML (Nesis, 1981/87). In Taningia tentacles are reduced to minute appendages in young subadults and are absent in adults. The second arms carry large, lidded photophores at the arm tips.

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Figure. Dorsolateral view of T. danae, 60 mm ML, Hawaiian waters. Photograph by R.Young.

Diagnosis

An octopoteuthid ...

• with large photophores at the tips of arms II; other arms without arm-tip photophores.
• without "tail" photophores.

Characteristics

1. Tentacles
   1. Reduced to minute appendages in young subadults.
2. Photophores
   1. Tips of Arms II modified into broad photophores with muscular lids. 
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   Figure. Aboral views of a large arm II photophore of T. danae. Left - The arm tip photophore with the lids closed. Right - Double photographic exposure that shows the lids withdrawn revealing the white surface of the photophore overlaying a second exposure with the lids closed. Photographs by R. Young and C. Roper.
   

Comments

Nomenclature

Behavior

Roper and Vecchione (1993) reported observations on bioluminescence in a 60 mm ML squid from Hawaiian waters. When disturbed, Taningia would attack and repeatedly flash the arm-tip photophores. The flash duration was generally only a fraction of a second; however on some occasions the arm tip glowed for periods of about 1-7 seconds. The aggressive flashing behavior is presumably used to startle predators via a mock attack. In addition, the visceral photophores were observed to glow for periods in excess of 15 min. and produced a general ventral glow. This latter behavior is suggestive of a counterillumination function (Roper and Vecchione, 1993). The photograph below left shows the squid on which these observations were made. The chromatophores are contracted on the midventral mantle skin which leaves a "window" for bioluminescent light from the viscera to emerge. The reflective photophores can be seen as a white streak. The photograph, below right, is from a different specimen that has the mantle cut open showing the visceral photophores.

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Figure. Left - Ventral view of T. danae, 60 mm ML squid, Hawaiian waters. Right - Ventral view of visceral photophores of T. danae seen through a cut in the ventral mantle. Photographs by R. Young and C. Roper.

Life History

The paralarva is distinctive in having enlarged suckers on the thick tentacles and the tips of arms II swollen by the developing photophores.

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Figure. Ventral view of the head of a paralarval T. danae, Hawaiian waters, mantle was misssing. Drawing by R. Young.

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Figure. Dorsal and oral views of a paralarva of T. danae, Gulf of Aden, 4.7 mm ML. Drawings from Chun, 1910. This is the paralarva that Naef (1923) named Octopodoteuthopsis persica.

The juvenile T. danae (photographs below) can be quite translucent although the armtip photophores are heavily pigmented. The eyes are large, and the central brain and optic lobes (yellow) occupy a posterior position in the head, leaving a long anterior esophagus passing to the buccal mass.

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Figure. Ventral (left) and dorsal-oblique views of a juvenile T. danae, ca. 10-20 mm ML, Hawaiian waters. Photograph by R. Young.

Distribution

The type locality is off the Cape Verde Islands. The distribution includes the tropical and temperate regions of all oceans and boreal waters of the North Atlantic (Roper and Vecchione, 1993).

References

Chun, C. 1910. Die Cephalopoden. Oegopsida. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition, "Valdivia" 1898-1899, 18: 1-522 + Atlas.

Naef, A. (1921/23). Cephalopoda. Fauna und Flora des Golfes von Neapel. Monograph, no. 35. English translation: A. Mercado (1972). Israel Program for Scientific Translations Ltd., Jerusalem, Israel. 863pp., IPST Cat. No. 5110/1,2.

Nesis, K. N. 1982/87. Abridged key to the cephalopod mollusks of the world's ocean. 385+ii pp. Light and Food Industry Publishing House, Moscow. (In Russian.). Translated into English by B. S. Levitov, ed. by L. A. Burgess (1987), Cephalopods of the world. T. F. H. Publications, Neptune City, NJ, 351pp.

Roper, C. F. E. and M. Vecchione. 1993. A geographic and taxonomic review of Taningia danae Joubin, 1931 (Cephalopoda: Octopoteuthidae), with new records and observations on bioluminescence. P. 441-456. In:: T. Okutani, R. K. O'Dor and T. Kubodera (eds.). The Recent Advances in Cephalopod Fishery Biology. Tokai University Press. Tokyo.

Young, R. E. 1972. The systematics and areal distribution of pelagic cephalopods from the seas off Southern California. Smithson. Contr. Zool., 97: 1-159.