The cephalopod family Histioteuthidae (Oegopsida): systematics, biology, and biogeography

This study is based on the large, mostly unreported collections of histioteuthids that have accumulated since the family was first revised by Voss in 1969. Of primary importance are the collections made in 1971, 1973, 1975/1976, and 1979 by the R/V Walther Herwig and the R/V Anton Dohrn in the Atlantic and the worldwide collections found in nine Russian or former Russian institutions. An investigation of the food and feeding of large juvenile to adult Histioteuthis celetaria pacifica (G. Voss, 1962) in the western Indian Ocean shows crustaceans and fishes to be the dominant items of prey and of about equal importance in the overall diet. The findings suggest that feeding occurs at approximately equal intensity in the sampled population near the bottom between 364 and 1000 m during both daytime and twilight. Maturity in the histioteuthids is accompanied by marked changes, not only in the genital organs, but also in the arms, especially arms I, which undergo marked secondary, symmetrical modification; in the photophores patterns, particularly on the arms and mantle where unusual, enlarged, darkly pigmented, simple photophores of different sizes and shapes appear in some species; and in the shape of the gladius and mantle in one species. Characters important in distinguishing among taxa include the photophore patterns on the mantle, around the right eyelid and on the arms, the sculpture of the dorsal pad of the funnel organ, the sucker enlargement pattern on the club, the development and structure of the inner web, the number of elements and the attachments of the buccal membrane, the single or double nature of the male genetalia, the internal structure of the spermatophore, the morphologies of the gladius and the lower beak, and the surface morphology of the skin. We recognize 13 species of the family Histioteuthidae in a single genus. Subspecies are recognized in two of the species, Histioteuthis celetaria (G. Voss, 1960) and H. corona (Voss and Voss, 1962), and the available material suggests that more than one taxon is represented in at least two other species, H. reversa (Verrill, 1880) and H. bonnellii (Ferussac, 1834). A key to the species and subspecies is given. Histioteuthis elongata (Voss and Voss, 1962) is the mature stage of H. reversa. The cosmopolitan, warm-water species H. hoylei (Goodrich, 1896), more commonly known in recent literature as H. dofleini (Pfeffer, 1912), comprises two separate, closely related species, H. hoylei in the Pacific and Indian oceans and//, arcturi (Robson, 1948) in the Atlantic. Investigation failed to clearly distinguish the two nominal subspecies of H. bonnellii, H. b. bonnellii and H. b. corpuscula Clarke, 1980, so H. bonnellii is restored, for the time being, to the status of an undivided species with two discrete, ecologically distinct northern and southern populations. A survey of the large new collections of H. meleagroteuthis (Chun, 1910) confirms that//, bruuni N. Voss, 1969, is a variant form of, and synonymous with, the senior species. Five species groups are characterized: the H. reversa species group, comprising H. reversa, H. atlantica (Hoyle, 1885), and H. eltaninae (N. Voss, 1969); the H. hoylei species group, comprising H. hoylei and//, arcturi; the//, bonnellii species group, comprising H. bonnellii and H. macrohista (N. Voss, 1969); the H. Miranda species group, comprising H. miranda (Berry, 1918) and the recently resurrected H. oceani (Robson, 1948); and the H. meleagroteuthis species group, comprising H. meleagroteuthis and H. heteropsis (Berry, 1913). Of the two species not belonging to a currently recognized group, H. corona and H. celetaria, a future, more detailed study than was possible with the available material of H. celetaria will probably result in the elevation of its two subspecies to the specific level, and together they will form the sixth distinct group of closely related species in the family. The distributional patterns nearly equal the number of taxa. The patterns show (1) a close correspondence with patterns of variations in environmental conditions in the oceans; (2) the important role of productivity on the formation of the patterns and in the determination of the abundance of a taxon within its range; and (3) the contiguous nature of the patterns of members of a species group or of subspecies of a polytypic, widespread species. Only three of the eight warm-water species in the family inhabit all three oceans, and of the three cosmopolites, only one is regarded as an undivided species. Of the four species or subdivisions of a species that have Southern Ocean-related patterns, two are typically circumglobal, and two are semicircumglobal. For the latter pair, the broad expanse of low nutrient waters of the central Pacific appears to act as an east-west barrier for dispersal. Although there are no strictly cold-water species or recognized subspecies in the northern hemisphere, two histioteuthids normally extend from warm water into north temperate or subarctic waters in the Atlantic. A tendency for some species or subdivisions of a species to be present in the eastern half of the Atlantic and absent in the western half is shared by both groups. The distributions of the four histioteuthids that are confined to the Pacific appear to be more restricted than are the distributions of purely Atlantic taxa. The differences in the patterns appear to reflect important hydrographical differences between the two oceans.

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