Lycoteuthis Pfeffer, 1900

Introduction

Species of Lycoteuthis are small squids with remarkable sexual dimorphism in body shape and photophore arrangement. Presumably they exhibit considerable bioluminescent courtship behavior which, unfortunately, has never been observed. These are thought to be mesopelagic squids, located primarily over island and continental slopes (Nesis, 1982), that undergo vertical migration into near-surface waters at night; however, little quantitative data on their vertical distribution has been obtained.

Diagnosis

A lycoteuthin ...

• with greatly elongate arms II in males.

Characteristics

1. Arms
   1. Arms II greatly elongate in males and carry a series of regularly spaced photophores on aboral surface.
   
   
2. Photophores.
   1. Two tentacular photophores in females (more in males).
   2. Three abdominal photophores.
   3. Embedded, laterally compressed tail photophore (?) (see Toll, 1983).
   4. Males with additional photophores on arms III, head, mantle.
   
   
3. Viscera
   1. Male genetalia paired.

Comments

Photophore patterns of males have not been completely described. A single, large photophore is present in males of L. springeri near the posterior tip of the gladius, and is laterally compressed (i.e. somewhat rod-like) and directed dorsally. This organ has not been described in males of L. lorigera but has not been looked for. Females of Lycoteuthis are very similar to females of Selenoteuthis but the latter is easily separated by the presence of the spherical terminal tail photophore.

Nomenclature

L. diadema was first described by Chun (1900) as Enoploteuthis diadema from two squid captured in the eastern South Atlantic. In 1903 he placed this species in Pfeffer's genus Lycoteuthis but later erected the genus Thaumatolampas (1903) for his species based on the photophores which had not been described by Pfeffer but were later (Pfeffer, 1912) shown to be identical with those of Chun's species. Pfeffer's type, Lycoteuthis jattai Pfeffer, 1900, based on material from dolphin stomachs, has been destroyed (Voss, 1962). Pfeffer (1912) considered "jattai" a "Museum name" and abandoned it. Voss (1958) demonstrated that the paralarval Astenoteuthion planctonicum Pfeffer, 1900 belonged in the synonomy of L. diadema. Voss (1962) also demonstrated that Robson's Leptodontoteuthis inermis from off South Africa belongs in the synomonm of L. diadema. Voss (1956) described Oregoniateuthis springeri which was distinguished by elongate arms II and an elongate tail, among other features. Toll (1983) found that Oregoniateuthis springeri was the sexually dimorphic male of Lycoteuthis diadema.

Steenstrup (1875) described Onychoteuthis lorigera which has the basic proportions of a male L. diadema and was found to be a male by Toll (1983). However, the type (180 mm ML) which was taken from a sperm whale stomach, is in poor condition (Voss, 1962) but is rather large. The type locality is "South Sea." L. lorigera was redescribed from a single male and found to lack the long tail characteristic of L. diadema (Forsch and Uozumi, 1990). Females in the catch were indistinguishable from L. diadema. Based on geography, L. diadema is assumed to be a synonym of L. lorigera and the North Atlantic "L. diadema" is L. springeri.

References

Chun, C. 1900. Aus den Tiefen des Weltmeeres. Gustav Fischer, Jena, 549pp.

Chun, C. 1903. Aus den Tiefen des Weltmeeres. Zweite Aufflage, Gustav Fischer, Jena, 592pp.

Chun, C. 1903. Uber Leuchtorgane und Augen von Tiefsee-Cephalopoden. Verh. Deutsche Zool. Ges., 13:67-91.

Förch, E. C. and Y. Uozumi. 1990. Discovery of a specimen of Lycoteuthis lorigera (Steenstrup, 1875) (Cephalopoda: Teuthoidea) from New Zealand and additional notes on its morphology. New Zealand Jour. Mar. Freshw. Res., 24: 251-258.

Pfeffer, G. 1900. Synopsis der oegopsiden Cephalopoden. Mitt. Hamburgischen Zoologische Museum.17: 147-198.

Pfeffer, G. 1912. Die Cephalopoden der Plankton-Expedition. Ergebniss der Plankton-Expedition der Humboldt-Stiftung. 2: 1-815.

Steenstrup, J. 1975. Hemisepius, in ny Slaegt af Sepia-Blaeksprutternes Familie, med Bemaerkninger om Sepia-Formerne I Almindelighted. K. Danske Vidensk. Selsk. Skr., ser. 5, 10: 465-482.

Toll, R. B. 1983. The lycoteuthid genus Oregoniateuthis Voss, 1956, a synonym of Lycoteuthis Pfeffer, 1900 (Cephalopoda: Teuthoidea). Proc. Biol. Soc. Wash. 96: 365-369.

Voss, G. L. (1956). Review of the cephalopods of the Gulf of Mexico. Bull. Mar. Sci. Gulf Carib. 6: 85-178.

Voss, G. L. (1958). The cephalopods collected by the R/V Atlantis during the West Indian cruise of 1954.. Bull. Mar. Sci. Gulf Carib. 8: 369-389.

Voss, G. L. 1962. A monograph of the Cephalopoda of the North Atlantic. I. The Family Lycoteuthidae. Bull. Mar. Sci. Gulf Carib. 12: 264-305.