Published online by Cambridge University Press: 11 May 2009
The chromatophore system of the small loliginid squid Alloteuthis subulata (Mollusca: Cephalopoda) is very simple and the repertoire of body patterns limited. There are red and yellow chromatophores only. On the dorsal mantle there are more yellows than reds; on the ventral mantle and there are more reds than yellows. The dorsal reds are larger than the yellows and bear more radial muscles. The significance of these findings is discussed.
Alloteuthis subulata Lamarck is a small loliginid, common in shallow water near Plymouth (Holme, 1974; Lipinski, 1985; Rodhouse et al., 1988). Little is known of its natural history and behaviour and chromatophores and body patterns of adults have never been described, although the skin of this species has been used in physiological studies of colour change (Messenger, 1991; Messenger et al., 1991; Cornwell & Messenger, 1995).
Over 100 adult animals of both sexes, caught by trawl at depths of 10–60 m, were examined; their mantle lengths ranged from 70 to 130 mm. Living animals were observed in large aquaria with circulating sea-water. Counts and measurements of chromatophores were made on colour photographs (taken through a Nikon dissecting microscope) of pieces of fresh skin (20×20 mm) dissected from animals killed by decapitation or after MgCl2 anaesthesia (Messenger et al., 1985). Chromatophores were counted first when fully retracted (by 1×10−3 M 5-HT) and then when fully expanded (with 1×10−3 M L-glutamate: Cornwell & Messenger, 1995). All measurements were made in the same area of the body: the central and anterior part of the mantle, dorsally and ventrally (Figure 2).