Cryptoteuthis brevibracchiata Collins, 2004

Introduction

Cryptoteuthis brevibracchiata is a bell-shaped opisthoteuthid with a semi-gelatinous body and short arms. It is known from a single, well preserved, female taken in a bottom trawl at 2274-2300 m that shows some features of both Grimpoteuthis and Opisthoteuthis. Considerable trawling in the area (Porcupine Seabight, eastern North Atlantic) failed to capture other specimens.

The generic name indicates the cryptic presence of the characters of both Opisthoteuthis and Grimpoteuthis. The specific name refers to the short arms. 

Brief diagnosis:

An opisthoteuthid ...

• with short arms.
• with small, lateral fins.
• with optic nerves passing through white body as a single bundle.

Full diagnosis of the genus (from Collins and Villanueva, 2006):

"Bell-shaped grimpoteuthids, with small fins and short arms. Gills with seven broad lamellae. Suckers broad, cirri moderate in length. Shell U-shaped, with parallel lateral walls terminating in two lobes. Posterior salivary glands absent. Radula absent. Digestive gland entire."*

* Refers a diagnosis of the genus within their family Grimpoteuthidae which also includes the genera Grimpoteuthis and Luteuthis.

Characteristics

1. Arms
   1. Arms short subequal in length.
      
   2. Single, prominent web-supporting nodule on ventral side of each arm at about sucker 25 on arms I, sucker 23 on arms II and III, sucker 22 on arms IV.
   

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   Figure. Dorsal and ventral views of C. brevibracchiata. Scale bar - 50 mm. Drawings from Collins (2004).

   3. Suckers broad; diameter increases to sucker 6 (4.2% of head width), following suckers of equal size to about web margin then decrease in size.
      
   4. Cirri moderate in length (6.5% of head width), slightly longer than sucker diameter; first cirri before third or fourth sucker; cirri extend to arm tips, longest on mid-arm.
      
   

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   Figure. First arm suckers and cirri of C. brevibracchiata, holotype. Top - Oral view of arm I (scale bar - 15 mm). Bottom left - Oral view of suckers and cirri (scale bar - 3 mm). Bottom right - Lateral view of suckers and cirri (scale bar - 5 mm). Drawings from Collins (2004). 

2. Head
   1. Optic lobes with spherical shape (see illustration under Viscera).
   2. Single bundle of optic nerves passes through white body enroute to eye.
   3. Radula absent.
      
      
3. Fins
   1. Fins short: fin span 76% of total length, 47% of head width.
      
      
4. Viscera and shell
   
   1. Gills large, half-orange form with 7 broad lamellae.
   2. Posterior salivary glands absent.
   3. Digestive gland a single lobe.
   4. Shell with broad U-shape, slightly flaring lateral wings; lateral wings terminate in lobe with point on dorsal side.
      
   

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   Figure. Left - Dorsal view of the digestive system and the relationships of the optic lobe, optic stalk and white body of C. brevibracchiata, holotype. Scale bar - 15 mm. Drawing from Collins (2004).

5. More details of the description of C. brevibracchiata can be found here.

Comments

The above description is from Collins (2004). In this paper Cryptoteuthis was placed in the family Grimpoteuhidae based on a molecular study by Piertney et al. (2003). This classification has not been used here as the authors of the Cirrata page of the Tree of Life felt that more supporting data are required before altering the existing classification (see Discussion of Phylogenetic Relationships on the Cirrata page).

C. brevibracchiata is most similar to species of Grimpoteuthis and Opisthoteuthis. It differs most clearly from Grimpoteuthis species in its smaller fins, its shorter arms, and in the peculiar termination of the lateral wing of the shell (i. e., blunt with short, narrow spike vs. blunt without spike) and it differs from Opisthoteuthis species most clearly in its shorter arms, single vs. three or four optic nerve bundles passing through/by the white body, spherical rather than kidney-shaped optic lobe, longer cirri, single vs. multiple web supports and shell with mostly blunt termination of the lateral wing of the shell vs. a pointed termination.

Distribution

Other Names for Cryptoteuthis brevibracchiata Collins, 2004

• Cryptoteuthis Collins, 2004

References

Collins, M. A. 2004. Cryptoteuthis brevibrancchiata: a new species and genus of cirrate octopod (Octopoda: Cirrata). Journal of Molluscan Studies. 70:263-267.