Idioteuthis cordiformisRichard E. Young and Michael Vecchione
The original description of I. cordiformis is based on a single male squid, 80 mm ML with intact tentacles, taken in the Indian Ocean near Sumatra. It has been subsequently described from Japan (Sasaki, 1929) and the Philippines (Voss, (1963). This is the largest of the mastigoteuthids reaching a size of 100 cm ML (A. Salcedo-Vargas, personnal communication).
Figure. I. cordiformis. Left - Ventral view of freshly captured squid, 325 mm ML. Photograph by Mark Norman. Right - Ventral view of the holotype, 83 mm ML. Drawing from Chun (1910).
A mastigoteuthid ...
- without photophores.
- with club bearing very large suckers (ca. 0.5 mm) at proximal end.
- with skin tubercules.
- Arms III much longer than arms I.
- TentaclesClick on an image to view larger version & data in a new window
Figure. Anteroventral view of I. cordiformis, same squid as in title photograph, showing tentacle club emerging. Note large club suckers. Submersible photograph at depth of 1200-1400 m. © Hawaii Undersea Research Laboratory, Univ. Hawaii, Marc Slattery, P.I.
- Proximal club suckers much larger than other club suckers.
- Largest proximal suckers 0.5 mm or larger.
- Funnel locking-apparatus ear-shaped with tragus and antitragus.
- Fin length (anterior extent to insertion on tail) 75% of ML (Chun, 1910).
- Mantle and other skin covered with small, conical tubercules arising from round plaques.
- Photophores and pigmentation
- Photophores absent.
- Most pigment in densely packed chromatophores.
Figure. Oral view of the tentacular club of I. cordiformis. Note the large suckers at the proximal end. Top - Holotype, 80 mm ML. Photograph by R. Young. Bottom - Large specimen (>30 cm ML), fresh, Australian waters. Photograph by Mark Norman.
Figure. Left - Ventral view of a portion of the eyelid of I. cordiformis, holotype, 80 mm ML, showing tile-like arrangement of tubercules. Photograph by R. Young. Right - Scanning electron micrograph with an external view of mantle tubercles of I. cordiformis, 87 mm ML, Philippine waters, 14°N, 121°E. The tubercules are very similar to those of Mp. hjorti. Photograph from Roper and Lu (1990).
Figure. Left - Histological section through a skin tubercule of I. cordiformis, holotype. Most of the epithelium has been lost except along one flank of the tubercule. Drawing from Chun (1910). Right - Cross-section through a tubercule of I. cordiformis using scanning electron microscopy. Photograph from Roper and Lu (1990).
The descriptions of Chun, Sasaki and Voss contain differences in the shape of the funnel locking-apparatus and the structure of the suckers. The significance of these differences remains to be determined. I. latipinna Sasaki, 1916 (see description under "Species of doubtful validity..." in the Nomenclature section of the family page) is probably a junior synonym of I. cordiformis.
I. cordiformis is most similar to Mp. hjorti but differs in the absence of ocular photophores and the presence of enlarged proximal club suckers among other features.
Type locality: Indian Ocean south of Sumatra at 0°15'N, 98°8'E. Also known from southern Japanese (Sasaki, 1929) and Philippine (Voss, 1963) waters.
Chun, C. 1910. Die Cephalopoden. Oegopsida. Wissenschaftliche Ergebnisse der Deutschen Tiefsee Expedition auf dem Dampfer "Valdivia" 1898-1899, 18(1):1-401.
Roper, C.F.E. and C.C. Lu 1990. Comparative morphology and function of dermal structures in oceanic squids (Cephalopoda). Smithson. Contr. Zool., No. 493: 1-40.
Sasaki, M. 1929. A Monograph of the Dibranchiate Cephalopods of the Japanese and Adjacent Waters. Journal of the College of Agriculture, Hokkaido Imperial University, 20(supplement):357 pages.
Voss, G. L. 1963. Cephalopoda of the Philippine Islands. Bull. U. S. Nat. Mus., 234: 1-180.
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- First online 16 July 2004
- Content changed 10 October 2017
Citing this page:
Young, Richard E. and Michael Vecchione. 2017. Idioteuthis http://tolweb.org/Idioteuthis_cordiformis/19510/2017.10.10 in The Tree of Life Web Project, http://tolweb.org/. Idioteuthis cordiformis . Version 10 October 2017.