Luteuthis O'Shea 1999

Introduction

Luteuthis spp. are very fragile, gelatinous, presumably pelagic cirrate octopods whose affinities are uncertain (see Nomenclature) The two species in this genus are known from only three specimens.

Diagnosis

Opisthoteuthids ...

• with distinctive shell. 

Characteristics

1. Shell
   1. W-shaped.
   2. Basal shelf deflected beneath saddle.
   3. Lateral wings with keeled, in some species, inrolled margins.
   image info

   Figure. Ventral and posterior views of shell of L. shuichi. Photograph from O'Shea and Lu, 2002.

2. Arms and web
   1. Sucker enlargement in males undetermined.
   2. Sucker apperature crenulate with tooth-like structures.
   3. First cirri between suckers 4 and 6.
   4. Cirri short; maximum length comparable to half of largest sucker diameter.
   5. Web nodules absent.
   image info

   Figure. Side and oral view of cut suckers showing tooth-like structures of L. dentatus. Drawing from O'Shea, 1999.

3. Pigmentation
   1. No areolar spots.


4. Gills
   1. Half-orange appearance.


5. Digestive system
   1. Intestine shorter than or approximately equal to esophagus (including crop) in length.
   2. Digestive gland bilobed.
   3. Radula present.
   image info

   Figure. Side view of the igestive system of L. dentatus. Drawing from O'Shea, 1999.

6. Reproductive system
   1. Male with linear arrangement of accessory glands.
   2. Penis well developed.


7. Optic lobe
   1. Circular in cross-section
   2. Single optic bundle penetrates the white body.
   image info

   Figure. Digestive system of L. dentatus. Drawing from O'Shea, 1999.

Comments

The two distinctive features of Luteuthis are the tooth-like structures on the suckers and the shape of the shell.

Nomenclature

The genus Luteuthis was established by O'Shea (1999) and placed in its own family, the Luteuthidae. O'Shea and Lu (2002) state that the family is distinguished by the following features:

• Presence of a radula.
• W-shaped shell.
• Suckers with tooth-like margins.
• Linear arrangement of accessory glands in the male.

The presence of a radula is now known be we widely distributed in the Grimpoteuthis. The W-shaped shell is unusual but an intermediate condition is seen in Grimpoteuthis tuftsiGrimpoteuthis). (O'Shea and Lu, 2002, consider this species to be in the Luteuthidae but Collins, in press, considers it a typical The peculiar suckers appears to be a unique feature. The arrangement of accessory glands needs further evaluation. The arrangement of glands is unknown in many species and where known the clear arrangement of the parts and, indeed, their proper identification is often unclear.

We suggest that placing Luteuthis in its own family is premature at present.

References

O'Shea, S. 1999. The marine fauna of New Zealand: Octopoda (Mollusca: Cephalopoda). NIWA Biodiversity Memoir 112: 280pp.

O'Shea, S. and C. C. Lu. 2002. A New Species of Luteuthis (Mollusca: Cephalopoda: Cirroctopoda) from the South China Sea. Zoological Studies, 41: 119-126.