Alloteuthis Wulker, 1920

Image: Photograph by Peter Wirtz

Alloteuthis contains three species.

Introduction

Small loliginids of the eastern Atlantic.

Brief diagnosis:

A loliginid ...

• with posterior mantle elongated as a tail-like structure; fins longer than broad.
• with a small conus someetimes apparent on gladius.
• with an Eastern Atlantic distribution

Characteristics

1. Arms
1. Hectocotylus:
1. Ventral crest absent.
2. Proximal suckers unmodified.
3. Proximal region with 10 - 12 (usually 11) normal suckers in ventral series followed distally by papillae.


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Figure. Oral view of the hectocotylus of Alloteuthis media, Gulf of Tunis, preserved. Photograph by R. Young.

2. Tentacles
1. a Tentacular clubs expanded, suckers in four series; two medial manal series with larger suckers.
   
   
3. Head
1. Buccal supports without suckers.
   
   
4. Mantle
1. Mantle long, relatively narrow; posterior end drawn out into narrow, pointed tail, up to 6 cm in adults.


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Figure. Ventral view of A. subulata showing dimorphism in the relative sizes and shapes of mature males. Top - Small male which we presume to be a sneaker male (sneakers are known in L. reynauldii - Hanlon, et al., 2002). Bottom - Large male with elongate tail. Females are approximately the same size and shape as the small male. Drawings from Naef (1921-3).

5. Fins
1. Fins reach posterior tip of mantle.
2. Fins heart-shaped, lateral angles rounded, posterior borders concave, extending posteriorly along tail.
   
   
6. Photophores
1. Photophores absent.
   
   
7. Viscera
1. Eggs small.
2. Spermatophore with small cement gland.

Comments:

Alloteuthis is morphologically very similar to Loligo and was considered by Vecchione et al. (1998) to be a subgenus.  However, molecular analyses by Anderson (2000) indicate that Alloteuthis should be a separate genus. This supports earlier inferences by Naef (1921-23) and Alexeyev (1989) that the presence of a gladial conus in Alloteuthis should be considered a generic character. The conus in Alloteuthis would clearly separate the genera but it can be very difficult to find and in some Alloteuthis specimens may be reduced until it is essentially absent. The posterior tip of the mantle in Alloteuthis is elongate into a tail-like structure that tends to be more pointed than in Loligo.  This is particularly true for males but identification of this character state can be subjective in females.

Distribution

Eastern Atlantic Ocean from about 55°-60°N to 20°S.

References

Anderson, F.E. 2000. Phylogeny and Historical Biogeography of the Loliginid Squids (Mollusca: Cephalopoda) Based on Mitochondrial DNA Sequence Data. Molecular Phylogenetics and Evolution 15: 191-214.

Alexeyev, D.O. 1989. Advantages and limitations of using the gladius in diagnosis of species and genera of the family Loliginidae (Cephalopoda). Zoologichesky Zhurnal, 68(6):36-42.

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.

Vecchione, M., T. F. Brakoniecki, Y. Natsukari and R. T. Hanlon. 1998. A provisional generic classification of the family Loliginidae. Smithson. Contr. Zool., 586.

Vecchione, M., E. Shea, S. Bussarawit, F. Anderson, D. Alexeyev, C.-C. Lu, T. Okutani, M. Roeleveld, C. Chotiyaputta, C. Roper, E. Jorgensen and N. Sukramongkol. 2005. Systematics of Indo-West Pacific loliginids. Phuket Mar. Biol. Cent. Res. Bull. 66: 23-26.