Ancistrocheirus lesueurii (Orbigny 1842)

Although only a single species is recognized in the Ancistroceiridae, differences in paralarval morphology between Atlantic and Pacific specimens suggest that more than one species exists (Young, et al., 1992).

Introduction

Ancistrocheirus lesueurii is of moderate size (about 25 cm maximum ML) and occupies tropical and subtropical waters of the world's oceans generally at mesopelagic depths. Adults may be associated with the ocean floor over the slope (Nesis, 1982/7). They bear hooks on the arms and tentacle clubs and have large sagittate fins. Photophores have a distinctive arrangement and appearance. Those on the ventral surface of the head and mantle occur in two very different size catagories.

Brief diagnosis:

A member of the enoploteuthid families ...

• with numerous, small integumental photophores, including photophores on the tentacles but without photophores on the eyeballs or viscera.

Characteristics

1. Head, arms, and tentacles
   1. Nuchal folds present.
   2. Hooks present on all arms.
   3. Tentacular clubs with hooks in two series on manus; suckers absent from manus; dactylus reduced.
      

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

      

      Figure. Left - Oral-lateral view of the tentacular club of A. lesueurii. Right - Enlarged view of the dactylus and terminal pad of the same club. Photographs by R. Young.
      

   4. Tentacles not modified near base; stalk "ligament" and vein leave tentacle at base and in a membrane.
      
      
2. Beaks
   
   1. Descriptions can be found here: Lower beak; upper beak.
      
      
3. Mantle, fins and gladius
   1. Fins slightly subterminal.
   2. Tail fleshy, large; vesicles absent.
   3. Gladius with long pointed rostrum.
      
      
4. Photophores
   1. Photophores on head and mantle in two distinct size classes.
   2. Photophores on head, funnel, arms, tentacular stalk, mantle and fins.
   3. Mature males with large, lidded, elongate photophores on aboral tips of arms IV; mature females with apparent photophores on tips of dorsal six arms.
      
   4. No photophores on eyeballs or viscera.
      
      
5. Viscera
   1. Nidamental glands present.
   2. Oviducal glands normal.
   3. Oviducts equally developed.

Comments

More details of the description of A. lesueurii can be found here. 

The number of large photophores on the mantle apparently increases through growth. A large mature female (180 mm Ml) from Hawaii had 24 of these organs.

Nomenclature

Orbigny (1834-48) described Enoploteuthis lesueurii in 1842 from the Indian Ocean, and Gray (1849) designated it the type species of his genus Ancistrocheirus. In 1851, Verany described Loligo alessandrinii from off Messina, Mediterranean; it was first placed in Calliteuthis Verrill, 1880 by Appellof (1890), then Pfeffer in 1900 reassigned it to his new genus Thelidioteuthis. Subsequently both genera and their species were synonomyzed (Nesis, 1978). The Enoploteuthidae, Pyroteuthidae and Ancistrocheiridae generally, have been considered subfamilies of the Enoploteuthidae. Clarke (1988) raised each subfamily to familial status and Young and Harman (1998) provided cladistic support for this arrangement.

A list of all nominal genera and species in the Ancistrocheiridae can be found here. The list includes the current status and type species of all genera, and the current status, type repository and type locality of all species and all pertinent references.

Life History

Figure. Dorsal view of a late paralarva of A. lesueurii. Note the long, broad brachial pillar (barely visible). Photograph by Jeffrey Milisen.

Paralarvae of A. lesueurii differ from those of other members of the enoploteuthid families by:

• Relatively small, broadly spaced eyes.
• Separation of the eyes from the arm bases.
• Gelatinous head tissues.
• Posterior position and kidney-bean shape of the digestive gland.

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

Figure. Paralarvae of A. lesueurii from Hawaiian waters. Far left (thumbnail) - Shows the relative size of the two stages. Left - 2.8 mm ML. Right - 6.2 mm ML; note that the ventral view shows 3 pairs of photophores on the mantle and 1 pair on the head. Each scale bar is 1 mm. Drawings by R. Young.

The tentacular clubs of advanced paralarvae are distinctive in having the suckers of the lateral series larger than suckers of the medial series.

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

   

Figure. Left - Anterior view of the same, late paralarva of A. lesueurii as above. Note the peculiar tentacular club and the photophores on the mantle and tentacles. Photograph by Jeffrey Milsen. Right - Drawing of the paralarval club, from Naef, 1921/23.

The early paralarvae can be confused with Octopoteuthis paralarvae by the large suckers on the clubs but are easily distinguished by the more numerous club suckers and more muscular tentacles in the former as well as the lack of a disc-shaped digestive gland characteristic of the latter genus.

Distristribution

Insufficient material has been available for critical species-level comparisons of specimens from different regions.

Other Names for Ancistrocheirus lesueurii (Orbigny 1842)

• Ancistrocheirus Gray 1849
• Ancistrocheiridae Pfeffer 1912

References

Appellof, A. 1890. Teuthologische Beitrage I. Ctenopteryx n.g., Veranya sicula Krohn, Calliteuthis Verrill. Bergens Museums Aarsbertning, 1889(3):1-34.

Clarke, M.R. 1988. Evolution of Recent Cephalopods - A Brief Review. pp. 331-340. In: M.R. Clarke and E.R. Trueman, (eds.), The Mollusca, Vol. 12, Paleontology and Neontology of Cephalopods. Academic Press.

Gray, J.E. 1849. Catalogue of the Mollusca in the Collection of the British Museum, Part I. "Cephalopoda Antepedia". London, British Museum (Nat. Hist.), 164 pages.

Naef, A. 1921-1923. Die Cephalopoden. Fauna e Flora del Golfo di Napoli, Monographie 35, Vol I, Parts I and II, Systematik, pp 1-863.

Nesis, K. N. 1978. The subfamily Ancistrocheirinae (Enoploteuthidae). Zoologichesky Zhurnal, 57(3):446-449. (In Russian, English summary).

Nesis, K. N. 1982. 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.

Okutani, T. 1974. Epipelagic decapod cephalopods collected by micronekton tows during the EASTROPAC expeditions, 1967-1968 (systematic part). Bull. Tokai Reg. Fish. Res. Lab., 80: 29-118.

Orbigny, A.d' 1834-48. In A. d'Ferussac and A. d'Orbigny, A., 1834-1848. Histoire Naturelle Generale et Particuliere Cephalopodes Acetabulifäres Vivants et Fossiles, J.B. Bailliere, Paris, 96 pages + LVI + 361 pages. Atlas of 144 plates.

Pfeffer, G. 1900. Synopsis der oegopsiden Cephalopoden. Jahrbuch der Hamburgischen Wissenschafthchen Anstalten, 17(2):147-198.

Verany, J.B. 1851. Cephalopodes de la Mediterranee. Mollusques Mediterraneens Observes, Decrits, Figures et Chromolithographies d'gores le vivant ouvrage dedii ASM le roi Charles Albert, I:1-132, 41 plates.

Young, R. E., L. A. Burgess, C. F. E. Roper, M. J. Sweeney and S. J. Stephen. 1998. Classification of the Enoploteuthidae, Pyroteuthidae and Ancistrocheiridae. Smithsonian Contr. to Zoology, 586: 239-255.

Young, R. E. and R. Harman. 1998. The phylogeny of the "enoploteuthid families." Smithson. Contr. Zool., No. 586: 257-270.

Young, R. E., Mangold, K. M., & Vecchione, M. (1992). The enoploteuthid group of families. Larval and Juvenile Cephalopods: a Manual for Their Identification. Smithson. Contrib. Zool, 513, 187–210.