Family VITRELEDONELLIDAE

Museums

Museum list

Regional Maps

Family VITRELEDONELLIDAE

Compiler and date details

C.C. Lu, National Chung Hsing University, Taichung, Taiwan

Introduction

Octopods of the pelagic monotypic family Vitreledonellidae Robson, 1930 have a gelatinous sac-like body. They are easily recognised by the long, slender, almost cigar-shaped digestive gland and simple gills, consisting of only the outer demibranchs; the inner demibranchs are absent. The arms are of moderate length and are connected by webs of about half the arm length. The arm suckers are in a single row, widely spaced within the web and close-set outside the web. There is a single wide mantle opening. The tip of the third left arm is hectocotylised and has a short ligula.

The sole member of this family Vitreledonella richardi was first described by Joubin in 1918, based on specimens captured in the North Atlantic. Joubin (1918) also provided detailed anatomical studies of the animal. Subsequent reports on taxonomy, anatomy and distributions are provided by Robson (1930, 1932) and Thore (1949). Lu & Phillips (1985) reported the species from Australian waters for the first time.

Very little is known of the biology of the species and nothing has been published on the specimens from Australian waters. The species has been reported as a component of the diet of Alepisaurus ferox captured in the South West Pacific (Rancurel 1970). Mature eggs are unknown; Vitreledonella richardi may be viviparous as large number of larvae were taken together with an adult female (Joubin 1937; Thore 1949). In the North Atlantic, specimens extend their bathymetric limits as they grow (Lu & Clarke 1975).

Vitreledonella richardi is found in the tropical-subtropical waters of all oceans. In Australian waters, it has been captured from the Coral Sea, Tasman Sea off Sydney and the Great Australian Bight (Lu 2001).

Diagnosis

The body is sac-like and gelatinous. The arms are of moderate length, in adults about two to three times the body length, and are connected by webs of about half the arm length. The arm suckers are in a single row, widely spaced within the web and close-set outside the web. There is a single wide mantle opening. The tip of the third left arm is hectocotylised with a short ligula. The digestive gland is long and slender, almost cigar-shaped. The gills consist of only the outer demibranchs, the inner demibranchs are absent. The eyes are small, rectangular and directed laterally. The radula is heterodont. The shell vestige is absent.