Teuthowenia Chun, 1910

Introduction

These are moderate-sized (140-380 mm gladius length), midwater cranchiids. Each species occupies a separate region of the world's oceans where primary productivity is relatively high. Paralarvae occupy near-surface waters until they reach a relatively large size of 50-100 mm ML.

image info

Figure. Lateral view of T. megalops in the "cockatoo" posture. Video still frame from a videotape recorded in-situ (Vecchione and Roper, 1991), JOHNSON SEA-LINK I submersible dive 2141; 4 August 1987; New England; depth = 789 m; temp. = 4.8° C; ML = 137 mm. An AVI format video clip of this animal is available at Cephalopods in Action

Diagnosis

A taoniin ...

• with three photophores on eyeball.
• with anterior third of fins attaching to mantle.

Characteristics

1. Tentacles
1. Club with suckers.
2. Stalk with four series of suckers and pads in distal 1/2 to 2/3.*
   image info

   Figure. Oral view of tentacle-cub of T. pellucida, 140 mm ML. Drawing from Voss (1985, p. 43. fig. 12g).

2. Funnel
1. Funnel valve absent.
2. Funel organ: Dorsal pad with three papillae.
   image info

   Figure. View of funnel organ of T. maculata, 123 mm ML. Drawing from Voss (1985, p. 33, fig.8f).

3. Mantle
1. Tubercles present (1-4) at funnel-mantle fusion.
   image info

   Figure. Ventral view of tubercule at funnel-mantle fusion of T. maculata, 123 mm ML. Drawing from Voss (1985, p. 33, 8e).

4. Fin
1. Anterior third or more inserts on mantle (in subadults) rather than shell-sac of gladius.***
   
   
5. Photophores
1. Three photophores on each eye.**
2. Photophores present on all arm tips of mature females.
   image info image info

   Figure. Left - Ventral and lateral views of an eye of T. maculata, 123 mm ML, showing ocular photophores. from Voss (1985, p. 33, fig. 8c,d). Right - Ventral view of the eyes of T. megalops, 134 mm ML, North Atlantic. Photographed during the MarEco cruise on the R/V G. O. SARS by R. Young.

*Unique in family but see Bathothauma and Megalocranchia.
**Unique in family.
***Unusual in family; shared with Egea.

Comments

Characteristics are from Voss (1980).

Life history

The best known species is T. pellucida. Juveniles begin an ontogenetic descent reaching bathypelagic depths as adults where they mate and spawn. Peculiar glands develop on the mantle of females at maturity that may produce a pheromone (Voss, 1985). In the dark, spacious waters of the bathypelagic zone locating a mate can be difficult. Presumably the production of a chemical attractant (pheromone) combined with the luminescence provided by the arm-tip photophores solves this problem. During mating discharged spermatophores (spermatangia) attach to the dorsal surface of the female then penetrate through the mantle wall and apparently discharge sperm into the mantle cavity (Voss, 1985). Females apparently spawn once then die.

Distribution

The three species appear to have non-overlapping distributions (Voss, 1985). Teuthowenia megalops occupies the subarctic and temperate waters of the north Atlantic Ocean. Teuthowenia maculata is found in the tropical waters of the eastern Atlantic Ocean. Teuthowenia pellucida occupies circum-global waters in the region of the subtropical convergence in the southern hemisphere.

References

Vecchione, M. and C. F. E. Roper. 1991. Cephalopods observed from submersibles in the western North Atlantic. Bulletin of Marine Science 49(1-2):433-445.

Voss, N. A. 1980. A generic revision of the Cranchiidae (Cephalopoda; Oegopsida). Bull. Mar. Sci. 30: 365-412.

Voss, N. A. 1985. Systematics, biology and biogeography of the cranchiid cephalopod genus Teuthowenia (Oegopsida). Bull. Mar. Sci. 36: 1-85.