277 Oceanography and Marine Biology: An Annual Review, 2006, 44, 277-322 © R. N. Gibson, R. J. A. Atkinson, and J. D. M. Gordon, Editors Taylor & Francis TAXONOMY, ECOLOGY AND BEHAVIOUR OF THE CIRRATE OCTOPODS MARTIN A. COLLINS 1 & ROGER VILLANUEVA 2 1 British Antarctic Survey, Natural Environmental Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, U.K. E-mail: macol@bas.ac.uk 2 Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas (CSIC), Passeig Marítim de la Barceloneta 37-49, E-08003 Barcelona, Spain E-mail: roger@icm.csic.es Abstract The cirrate octopods are deep-sea, cold-adapted cephalopod molluscs that are found throughout the world’s oceans, usually at depths in excess of 300 m, but shallower in cold water at high latitudes. The gelatinous bodies of the cirrates, which deform when preserved, coupled with low capture rates have caused considerable confusion in the systematics of the group. The taxo- nomically relevant morphological features are briefly reviewed and the taxonomy revised. On the basis of morphological and molecular information the cirrates are divided into four families, the Cirroteuthidae (including the genera Cirroteuthis, Cirrothauma and Stauroteuthis), Cirroctopodidae (Cirroctopus), Grimpoteuthidae (Cryptoteuthis, Grimpoteuthis and Luteuthis) and Opisthoteuthidae (Opisthoteuthis). A total of 45 species are recognised. The opisthoteuthids are primarily benthic animals, the grimpoteuthids and cirroctopodids benthopelagic and the cirroteuthids essentially pelagic, but generally close to the sea floor. With the exception of two common, shallow, Opistho- teuthis species, the biology of the cirrates is poorly studied. The data on reproductive biology indicate that spawning is extended, with growth continuing during a reproductive period that probably occupies much of the life cycle, an unusual strategy in cephalopods. Diet studies suggest that benthic cirrates feed on small-sized organisms with low swimming speeds and the main prey are amphipods and polychaetes. Cirrate predators include sharks, teleost fishes, fur seals and sperm whales. Behav- ioural observations, based on underwater photographs, submersible observations and aquarium studies, show a range of postures, modes of locomotion and responses to disturbance that differ between the families. Behavioural observations also help interpret the unusual morphology and physiology of the cirrates, such as the use of cirri, fins, secondary web and bioluminescent emissions. Introduction The cirrate octopods are deep-sea cephalopod molluscs, possessing a semigelatinous body, paired fins, well-developed web, a large internal shell and paired cirri between a single row of suckers. The morphology of the cirrates indicates that the group are relatively primitive, with similarities to ancestral octopods (Young et al. 1998). However, molecular studies of cephalopod evolution have produced mixed results, with no clear monophyly in the Octopoda (incirrates and cirrates) and the suggestion of polyphyly in the cirrates (Carlini et al. 2001, Lindgren et al. 2004). The cirrates are known from all oceans, typically at depths of 300–7000 m, but are found shallower in cold waters at high latitudes (Voss 1967, 1988a) and include some of the largest © 2006 by Taylor & Francis Group, LLC MARTIN A. COLLINS & ROGER VILLANUEVA 278 invertebrates in the deep sea. They are usually caught in small numbers, are extremely fragile and easily damaged on capture, and often distort during preservation. Many of the early descriptions of species, genera and families were based on small numbers (often one) of badly damaged and poorly preserved specimens (e.g., Cirroteuthis muelleri (Eschricht 1836), Cirrothauma magna (Hoyle 1885), Grimpoteuthis umbellata (Fischer 1883), Opisthoteuthis massyae (Grimpe 1920)). These factors have led to considerable confusion in the taxonomy of the group, with debate about which characters should be used to separate genera and families and consequently the classification of the cirrates has been in an almost constant state of flux, with species being moved between genera and genera between families (e.g., Robson 1930, Nesis 1987, Voss 1988a, Sweeney & Roper 1998). Studies of the morphology of the cirrates have, with a small number of exceptions (Meyer 1906, Ebersbach 1915, Robson 1932, Aldred et al. 1983), been limited to brief taxonomic descrip- tions and some of the early detailed studies have been confounded by confusion over the definition of structures and of the species being examined. The development of new technology, allowing access to the deep sea (e.g Roper & Brundage 1972, Villanueva et al. 1997) and the extension of commercial fishing into deeper water (Boyle et al. 1998), has stimulated renewed interest in this enigmatic group in the last 20 yr. Much of the recent work has focused on taxonomy and distribution (e.g., O’Shea 1999, Collins et al. 2001a, Villanueva et al. 2002, Collins 2003), ecology of the relatively shallow species (e.g., Villanueva & Guerra 1991, Boyle & Daly 2000) and in situ behavioural observations from submersibles (Vec- chione & Young 1997, Villanueva et al. 1997, Johnsen et al. 1999a,b). Correct identification is important to all studies, but taxonomic work has been handicapped by the poor state of type specimens, rather confused literature and problems with definitions of anatomical structures. Ecological studies of the cirrates have, largely through lack of specimens, been limited to shallow species of the Opisthoteuthis genus, which have been caught as by-catch of commercial fisheries (Cupka 1970, Vecchione 1987, Villanueva & Guerra 1991, Villanueva 1992a, Boyle et al. 1998, Laptikhovsky 1999, Daly et al. 1998, Boyle & Daly 2000), but little or no ecological work has been undertaken on the deeper species. The existing data indicate important differences in reproduction between the cirrate and incirrate octopods, notably in lack of seasonality associated with spawning and the continuous production of eggs and spermatophores in adult individuals of the species studied to date. During recent years in situ and aquaria observations of live cirrates have dramatically changed our understanding of how these animals use their fins and web to swim and respond to external disturbance (e.g., Boletzky et al. 1992, Vecchione & Young 1997, Villanueva et al. 1997, Villanueva 2000). These behavioural observations have been indispensable in interpreting the morphological characteristics of the cirrates, such as the delicate secondary web and the bioluminescent capabilities (Johnsen et al. 1999a,b), and suggest that future observations on live specimens will produce new findings and help explain the function of other unusual morphological features such as the areolar spots and mantle ‘windows’. Here the taxonomy of the group is reviewed and updated and the limited data on ecology and behaviour summarised. To underpin the taxonomic review, the first section briefly compares the anatomy of the different genera and families. Comparative anatomy This section is intended to provide the reader with details of the comparative anatomy of the cirrates to facilitate identification and taxonomic descriptions. For a detailed study of the anatomy of a cirrate (Cirrothauma murrayi) the reader is referred to Aldred et al. (1983). The cirrates are essentially deep-water forms, and exhibit a number of characteristics that are considered modifications to deep-sea life (reduction or loss of radula and posterior salivary glands; © 2006 by Taylor & Francis Group, LLC CIRRATE OCTOPODS 279 loss of ink sac; reduction of gills; narrowing of funnel aperture; large eggs), which are shared by deep incirrate species (Robson 1925, Voss 1988b). The gelatinous nature and few hard parts of the cirrates mean that preservation can dramatically change the form of the animal, and this has been clearly demonstrated with whole animals (e.g., Luteuthis shuishi (O’Shea & Lu 2002) and Cryptoteuthis brevibracchiata (Collins 2004) where comparisons of fresh and preserved specimens are illustrated). Different preservatives will cause different types of distortion, with considerable shrinkage of Cirro- teuthis, Cirrothauma and Stauroteuthis in alcohol. Freezing may also cause distortion, notably to the internal shell (Collins 2003) and possibly spermatophores (Villanueva et al. 2002). Guidelines for dealing with captured specimens were produced at a workshop in 2000 (Vecchione & Collins 2002). External Externally the cirrates are characterised by the possession of lateral to terminal fins and paired cirri, which are interspersed between a single row of suckers that are highly variable in form. The body is semigelatinous and varies from an extended bell-shape with long arms (Cirroteuthidae) through bell-shaped forms with moderate arms (Grimpoteuthidae) to the ovoid shaped Opistho- teuthis (Figure 1 and Figure 2). Fin size varies from large in Cirroctopus, Cirroteuthis and Cirrothauma through moderate (Grimpoteuthis, Luteuthis and Stauroteuthis) to small (Cryptoteuthis and Opisthoteuthis). The fins are generally larger in juvenile cirrates than in adults (Figure 2G). Figure 1 Ventral view of basic body form in the cirrate octopods. (A) Cirroteuthis muelleri, (B) Cirrothauma murrayi, (C) Stauroteuthis syrtensis, (D) Grimpoteuthis discoveryi, (E) Opisthoteuthis massyae, (F) Cirroc- topus glacialis. Sources (with permission where required): (A, B, F) Collins unpublished; (C) from Collins & Henriques (2000); (D) from Collins (2003); (E) from Villanueva et al. (2002). Scale bars = 100 mm. © 2006 by Taylor & Francis Group, LLC MARTIN A. COLLINS & ROGER VILLANUEVA 280 The cirrates lack the innervated chromatophores that are found in shallow-water cephalopods (Aldred et al. 1983, Nesis 1987), and are therefore not capable of colour change. In most species the skin is pigmented and is an orange/red/purple colour in fresh specimens of Opisthoteuthis, Figure 2 (See also Colour Figure 2 in the insert following page 276.) Photographs of cirrate octopods. (A) dorsal view of Opisthoteuthis massyae (fresh specimen), (B) ventral view of Cryptoteuthis brevibracchiata (fresh specimen), (C) dorso-posterior view of Cirroctopus glacialis (fresh specimen), (D) ventral view of Grimpoteuthis discoveryi (formalin-preserved specimen), (E) ventral view of Cirrothauma murrayi (fresh specimen), (F) oral view of male Stauroteuthis syrtensis (formalin-preserved specimen), (G) Juvenile specimen of Opisthoteuthis calypso, note the relatively large fins and funnel in comparison with the adult Opisthoteuthis in (A). Sources (with permission where required): (A) Collins unpublished; (B) from Collins (2004); (C) Mike Vecchione unpublished; (D) from Collins (2003); (E) from Aldred et al. (1983); (F) from Collins & Henriques (2000); (G) L. Dantart. Scale bars: (A–F) = 100 mm; (G) = 10 mm. © 2006 by Taylor & Francis Group, LLC CIRRATE OCTOPODS 281 Grimpoteuthis, Luteuthis, Cryptoteuthis and Cirroctopus. In the Cirroteuthidae the oral surface of the arms is usually deep purple in colour, with the rest of the body pale or unpigmented, although in situ photographs do show cirroteuthids with purple, red and/or brown colour in both oral and dorsal surfaces. Although much of the external tissue of Stauroteuthis is translucent, the internal organs are surrounded by a pigmented membrane, which has a ‘window’ of unknown function in the area of the accessory glands in males and oviducal glands in females (Collins & Henriques 2000). In Cirrothauma murrayi the pigmentation occurs in two layers: an outer layer that contains many small granules and an inner layer containing spherical clusters of pigment granules (Aldred et al. 1983). Pigment-free (areolar) spots are seen on some species of Opisthoteuthis and Cirroctopus (Vecchione et al. 1998, Villanueva et al. 2002), and Vecchione et al. (1998) speculated that the pigment-free spots in Cirroctopus glacialis gather and channel light. The arms vary in length from short to moderate in Opisthoteuthis and Cryptoteuthis, moderate in Grimpoteuthis, Luteuthis and Cirroctopus and long in Cirroteuthis, Stauroteuthis and Cirrothauma. In many species the arms are of approximately the same length, and if there are differences, it is usually the dorsal arms that are the longest. In at least two species of Opisthoteuthis (O. massyae and O. hardyi) the dorsal arms of the mature males are considerably thicker than the other arms (see Villanueva et al. 2002). The function of the thickened arms is not known. The cirrates do not possess a hectocotylus (the modified arm of male incirrate octopods, used to transfer spermatophores to the female). In all cirrates the arms are connected by a deep web, which occurs in two forms. In Opistho- teuthidae, Grimpoteuthidae and Cirroctopodidae the arms are directly connected to the web (Figure 3B), whilst in Cirroteuthidae each arm is independent of the primary web and is connected to it by a single, delicate vertical membrane (the intermediate or secondary web) that is attached along the dorsum of the arm (Figure 3A; see Vecchione & Young 1997). The secondary web of the Cirroteuthidae may allow greater flexing in the web, and therefore greater locomotory capacity (see section on behaviour, p. 310). The web is particularly thin and delicate in the Cirroteuthidae, but thicker and tougher in the other families. In Cirroteuthis muelleri and many Grimpoteuthis species (Voss & Pearcy 1990, Collins 2003) the web is supported by a single fleshy nodule at the Figure 3 Cross section of the arm and web of (A) Stauroteuthis syrtensis and (B) Cirroctopus glacialis contrasting the complex web (secondary web) of S. syrtensis with the simple web form of C. glacialis. From Vecchione & Young (1997). With permission. © 2006 by Taylor & Francis Group, LLC MARTIN A. COLLINS & ROGER VILLANUEVA 282 web margin on the ventral side of each arm (see Figure 4E). Opisthoteuthis species lack these single fleshy nodules, but instead the web is supported, in some species at least, by multiple, thin, web supports also placed at the web margin (Figure 4D). In Cirrothauma murrayi the web extends right to the arm tips (Aldred et al. 1983). The arms carry a single row of suckers of highly variable form (Figure 4), with distinct sexual dimorphism in many species. In Opisthoteuthis the suckers are embedded in the arms, with two distinct enlarged fields in mature males, the proximal enlarged field typically occupies suckers 3–8, whilst the location, number and degree of enlargement of the distal field is generally species specific, with gross enlargement in some species (e.g., O. calypso, see Villanueva et al. 2002). In females the suckers increase gradually in size to a single maximum. In Grimpoteuthis and Cirroctopus the suckers increase to reach a single maximum, somewhere between sucker 8 and the web margin. In many Grimpoteuthis species the suckers also show sexual dimorphism, with suckers larger in males than females but in G. tuftsi and G. challengeri there is no apparent sexual dimorphism. In mature specimens of Grimpoteuthidae and Opisthoteuthidae total sucker counts vary between 50 and 120 suckers. Sucker form is either barrel-shaped or cylindrical in Grimpoteuthis and distinctly barrel-shaped in Opisthoteuthis and Cirroctopus. The suckers of Opisthoteuthis have a distinct peduncle, with the infundibulum composed of radially arranged cushions similar to incirrate octopods (Villanueva & Guerra 1991) (Figure 5A,B) and the suckers of the other Opisthoteuthidae and Grimpoteuthidae appear similar in basic structure. The suckers of the Cirroteuthidae are highly modified. In Stauroteuthis syrtensis the suckers are highly sexually dimorphic, with very small suckers in the females (maximum sucker diameter (MSD) = 2.2 mm), but considerably larger in the males (MSD = 6.5 mm; Collins & Henriques 2000) (Figure 5E). In both sexes the first 5–6 (oral) suckers are close together, then 7–23 are spaced out, with maximum intersucker distance between suckers 13 and 14, with the distal suckers small and closely packed (Figure 4G–I). From behavioural, anatomical and ultrastructural examination, Johnsen et al. (1999a,b) considered the suckers of S. syrtensis to be photophores, not true octopodan suckers. These suckerlike photophores have the capability for bioluminescent emission, but it is not clear if the suckers of both males and females produce light (Collins & Henriques 2000). These findings suggest that careful observations of living material and ultrastructural examination may be useful in other species of cirrates. The function of the light could be to attract either food or mates. In S. gilchristi there is no dimorphism in sucker form, and the bioluminescent capability is not known. In Cirrothauma murrayi the first 5–6 (oral) suckers are small, rounded and closely packed, and somewhat similar to the oral suckers of Stauroteuthis, but the remaining suckers are borne on long, conspicuous, fleshy peduncles (see Figures 4J,K; 5D,E; Aldred et al. 1983). The oral suckers have a small orifice in the infundibulum, but lack a suction chamber. There is no orifice in the distal suckers, with the infundibulum resembling a small cap (Figure 5C,D). It has been suggested that there is a possible light organ at the base of the fleshy peducle of the distal suckers (Chun 1913; Aldred et al. 1982, 1983), but this has not been confirmed (Aldred et al. 1984). In Cirroteuthis muelleri the oral suckers (1–8) are the largest and are tightly packed, cup-shaped and raised on broad heavy pads (Voss & Pearcy 1990). The distal suckers appear nonfunctional (as adhesive suckers) and are raised on fluid filled peduncles, similar in form to those of Cirrothauma murrayi, but they stop at the web margin (Voss & Pearcy 1990). Three types of suckers are found on the arms of Cirrothauma magna (Guerra et al. 1998): the oral suckers are small, closely packed and cylindrical, mounted on a stout stalk; mid-arm suckers have a long stalk and an inflatable acetabulum chamber; distal suckers are bowl-like with a rigid muscular base. The cirri are thought to have a sensory function (Aldred et al. 1983) and vary in length, arrangement and internal structure between genera. In the Cirroteuthidae the cirri are extremely long, particularly on the midsection of the arms (approximately 50% of mantle length (ML) in © 2006 by Taylor & Francis Group, LLC 283 CIRRATE OCTOPODS Figure 4 Illustrations of the arms, suckers and cirri form in the cirrate octopods. Opisthoteuthis agassizii: (A) arm, (B) enlarged male suckers and cirri, (C) female suckers and cirri, (D) web supports. Grimpoteuthis boylei: (E) arm, (F) suckers and cirri. Stauroteuthis syrtensis: (G) arm, (H, I) male suckers and cirri from (H) oral and (I) mid-arm sections. Cirrothauma murrayi: (J) arm, (K) suckers and cirri. Cirroctopus glacialis: (L) arm. Cryptoteuthis brevibracchiata: (M) arm, (N) suckers and cirri. Sources (with permission where required): (A–D) from Villanueva et al. 2002; (E–F) from Collins 2003; (G) from Collins & Henriques 2000; (H–L) Collins, unpublished; (M-N) from Collins 2004. Unmarked scale bars = 10 mm. © 2006 by Taylor & Francis Group, LLC MARTIN A. COLLINS & ROGER VILLANUEVA 284 Figure 5 Detail of suckers and cirri. (A, B) Scanning electron micrographs of suckers of Opisthoteuthis calypso (sp, sucker peduncle; inf, sucker infundibulum), (C) Section of mid-arm sucker of male Stauroteuthis syrtensis, (D) Scanning electron micrograph of Cirrothauma murrayi sucker, (E) Sagital section of stalked sucker of Cirrothauma murrayi, (F) Scanning electron micrograph of cirrus of Opisthoteuthis calypso, (G) longitudinal section of Cirrothauma murrayi cirrus (sep = septum). Sources (with permission where required): (A, B, F) from Villanueva & Guerra (1991); (C) Collins unpublished; (E, D, G) from Aldred et al. (1983). Scale bars: (A, B, C, E, F, G) = 0.5 mm; (D) = 2 mm. © 2006 by Taylor & Francis Group, LLC CIRRATE OCTOPODS 285 Stauroteuthis; Collins & Henriques 2000). In Stauroteuthis, Cirroteuthis and Cirrothauma magna the cirri are absent from the distal parts of the arms, stopping at the web margin. In Cirrothauma murrayi, both the web and cirri extend to the distal ends of the arms. In the other families the cirri continue to the arm tips and are of moderate length in the Grimpoteuthidae but typically short and stubby in Opisthoteuthidae and Cirroctopus. Cirri are usually absent between some of the oral suckers, but the location of the first (oral) cirrus varies between species. In Cirrothauma murrayi the long cirri are divided internally by transverse septa (Figure 5G; Aldred et al. 1983), but these septa were not seen in the shorter cirri of Opisthoteuthis massyae (Villanueva & Guerra 1991). In O. massyae, the cirri are composed of sensory tissue surrounded by muscle (Villanueva & Guerra 1991), similar in structure to O. depressa (Meyer 1906). Hochberg et al. (1992) reported that cirri are absent in early juvenile forms of some Opisthoteuthis sp., however juvenile Opisthoteuthis calypso have well-developed cirri, that are relatively longer (in relation to sucker diameter) than adults (Villanueva unpublished). Early juveniles of Cirrothauma murrayi also possess well-developed cirri (Aldred et al. 1983). The funnel form is variable, being extremely long in Cirrothauma, but relatively short in the other genera. The mantle aperture is reduced, probably associated with the reduction or lack of jet propulsion. In Stauroteuthis it is extremely reduced, such that on preservation it appears as a small pore in the mantle, with the funnel often contracted inside. The funnel organ, which is a useful taxonomic character in the incirrate octopods, is rather indistinct in the cirrates, but in those species for which it has been described, it is an inverted V-shape (e.g., Berry 1918, Voss & Pearcy 1990, Collins 2003). The eyes are large in all but Cirrothauma, which has greatly reduced eyes that lack an iris and lens (see Aldred et al. 1983). Rounded, prominent olfactory organs are found within the mantle aperture and either side of the funnel in all cirrate species. They are served by a complex nerve net, but their supposed chemosensory function has not been established. Internal The arrangement of organs in the mantle cavity is similar in all cirrates (Figure 6), but the structure of the gills and the digestive system is variable. The gills of the cirrates are of two basic forms, the sepioid form is found in the Cirroteuthidae and the half-orange or modified half-orange form in the other families (Figure 6). The gills are divided into a series of lamellae, which in the sepioid form are arranged linearly, whist in the half-orange form they are grouped like segments of an orange. Opisthoteuthidae, Grimpoteuthidae and Cirroctopus and have the half-orange form, but the number and form of the lamellae varies between species. In Grimpoteuthis, G. challengeri and G. tuftsi possess very fine lamellae and small gills, but the other species have broad lamellae and larger gills. Associated with each gill is a branchial heart, which leads to the systemic heart. A detailed description of the circulatory system of Stauroteuthis syrtensis and Grimpoteuthis is given by Ebersbach (1915), and Aldred et al. (1983) describe interspecific differences in the structure of the cirrate heart. The internal shell is distinct in each of the genera (Figure 7; see Bizikov 2004 for detail of the form and evolution of the shell). The vacuolated cartilage of the shell becomes distorted during freezing, so caution should be exercised when examining frozen material. In Cirroteuthis muelleri the shell is saddle-shaped, with large ‘wings’ associated with the large fin muscles. Cirrothauma magna and C. murrayi possess a butterfly-shaped shell, a character that unites these species in Cirrothauma (see O’Shea 1999). In Stauroteuthis the shell is a simple U-shape. The shell of Cirroctopus is V-shaped, whilst those of Grimpoteuthis, Opisthoteuthis and Cryptoteuthis are U-shaped. The shells of Opisthoteuthis and Cirroctopus have lateral walls that taper to fine points, whilst those of Grimpoteuthis and Cryptoteuthis either end bluntly or in two lobes. Luteuthis has © 2006 by Taylor & Francis Group, LLC MARTIN A. COLLINS & ROGER VILLANUEVA 286 a distinctly W-shaped shell. The shell is tightly bound in the shell sac, to which the fins adhere. The fins, which contain the most robust muscle in the cirrate octopods (Vecchione & Young 1997), are divided into distinct proximal and distal regions (Figure 8). The proximal region has a central cartilaginous core, which is covered by thick bundles of muscle fibres, parallel to the fin axis, that insert on the shell sac or on the cartilaginous core. The distal region lacks the cartilaginous core of the proximal region, consisting of two layers of thin muscles that are oriented transversely to the fin plane. The digestive system is similar in all the cirrates (Figure 9) consisting of buccal mass and beaks, radula (in some species), anterior and posterior (reduced or absent) salivary glands, oesoph- agus, stomach, caecum, digestive gland and intestine. The beak form varies between the genera (Figure 10), with Stauroteuthis possessing a particularly distinct beak, although insufficient material has been examined to distinguish interspecific variability. A radula is only found in some species of Grimpoteuthis (Figure 11) and in Luteuthis, but in a highly reduced monodont form (Voss & Pearcy 1990, O’Shea 1999, Collins 2003). Anterior salivary glands are present in all species, but posterior salivary glands are only reported in two species of Grimpoteuthis, where they are small (Collins 2003). Aldred et al. (1983) did report a single posterior salivary gland in Cirrothauma, but the location of the single gland is different to Grimpoteuthis and incirrate octopods and is possibly not an analagous structure. The oesophagus, stomach and intestine are a deeply pigmented purple colour that may be associated with the consumption of bioluminescent prey (Vecchione & Young 1997). A swelling of the oesophagus (crop?) has been reported for some species, but is rather indistinct. The stomach, which lies in a groove in the digestive gland, is lined with a thick cuticle and leads, via a narrow duct, to the caecum, which typically has a single turn and is connected to the digestive gland by two digestive ducts. The digestive gland consists of a single lobe in most species but is bilobed (two discrete lobes) in some Opisthoteuthis species and in Luteuthis. The intestine is straight (uncoiled) in Cirroteuthis, Stauroteuthis and Cirrothauma but slightly coiled in the other genera. The basic form of the nervous system is similar for all the cirrates and is described in detail for Cirrothauma murrayi by Aldred et al. (1983). A major difference between the cirrates and incirrates is the form of the central ganglia, which in cirrates consist of two rings surrounding the Figure 6 Internal anatomy of (A) female Grimpoteuthis wuelkeri and (B) male Stauroteuthis syrtensis illus- trating the gill form and location of internal organs. Sources (with permission where required): (A) from Collins (2003); (B) Collins unpublished. Scale bars = 25 mm. © 2006 by Taylor & Francis Group, LLC [...]... crangonid or hippolytid shrimp and sand Crustacea: Macrura Natantia and Reptantia, amphipods and isopods Mostly polychaetes, gammarid amphipods, mysids and decapods, also tanaids, ostracods, copepods, isopods, bivalves and cumaceans Crustaceans, shrimps and fishes 1 1 Several Vecchione & Young 1997 Voss 19 56 Cupka 1970 2 Lipka 1975 8 Pereyra 1 965 5 Alcazar & Ortea 1981 reported as O agassizii Villanueva... seminal vesicle, accessory gland(s) and terminal organ (or penis) (Figure 14) The testis is located posteriorly in the mantle cavity, and leads via the vas deferens to the seminal vesicle, which passes through the accessory gland(s) to the terminal organ The number and size of the accessory glands vary between genera and species In the Cirroteuthidae there is a single accessory gland (Aldred et al 1983,... and 2–172 (mean: 72) in O massyae (Villanueva 1992a) The biochemical composition of the mature male gonad of Opisthoteuthis sp shows low protein (50 .6 % dry weight) and total amino acid (protein-bound + free amino acids: 46. 6 % dry weight) content and high lipid (11.4%) and cholesterol (2.3%) values (Rosa et al 2005) In O massyae, the genital complex in mature females constituted a mean of 2 .6% (range... trawl 68 6–823 1** Bottom trawl 483–490 Bottom trawl Location References Collins et al 2001a 6 23 Porcupine Seabight and Abysal Plain, NE Atlantic Porcupine Seabight and Abysal Plain, NE Atlantic Porcupine Seabight, NE Atlantic Porcupine Seabight, NE Atlantic Porcupine Seabight and Abysal Plain, NE Atlantic Off Columbia River, NE Pacific Off Namibia, SE Atlantic 829–8 36 202–499 Off Namibia, SE Atlantic... Photographic survey 2 360 –37 86 2000 Porcupine Seabight and Abysal Plain, NE Atlantic Bahamas Islands, NW Atlantic Arctic Ocean 3900 5000 4300 2500 98 32 1.1 1.3 Opisthoteuthis californiana Opisthoteuthis calypso Opisthoteuthis massyae Unidentified cirrates (average) (average) (average) (average) Virgin Island Basin, NW Atlantic Blake Basin, NW Atlantic Bermuda, NW Atlantic Northeast Channel, NE Atlantic Collins... Opisthoteuthis and Grimpoteuthis, with the body shape and short fins characteristic of Opisthoteuthis whilst the form of the shell, optic nerve configuration and the size and shape of suckers and cirri resemble Grimpoteuthis There is a superficial resemblance to Luteuthis shuishi, but Cryptoteuthis brevibracchiata possesses an entire digestive gland, U-shaped shell, cirri of moderate length and lacks a radula... including tanaids, cumaceans, mysids, ostracods, decapods and copepods also taken (Villanueva & Guerra 1991) A number of other studies have reported on the diet of small numbers of specimens, indicating a common trend in cirrates of feeding on small-sized organisms with low swimming speeds (Table 7) Suckers and cirri seem to play an important role in chemo- and mechanoreception in Opisthoteuthis (Villanueva... diameter), adapted to handling small 307 © 20 06 by Taylor & Francis Group, LLC MARTIN A COLLINS & ROGER VILLANUEVA Table 7 Main prey recorded from stomach contents in cirrate octopods Sample Size References Crustacea, mostly copepods Amphipods, mysids and polychaetes Polychaetes, cumaceans, amphipods, calanoid copepods and decapod crustaceans Decapod crustaceans, octopod beaks and foraminiferans Copepods, isopods,... recently described from Atlantic and New Zealand waters O brunni is included in this genus rather than Grimpoteuthis (see Collins 2003) O’Shea (1999) separated the genus into three types based on the form of the digestive gland (bilobed or entire), shell, enlarged suckers and male accessory glands, but that organisation is not followed here Six species are reported in the Atlantic, and the confusion surrounding... (Joubin, 1903) NE Atlantic from SW Ireland to South Africa and Mediterranean ( 365 –2208 m) Off New Zealand (850–1500 m) N Pacific, off Japanese coast Previously misidentified as O agassizii Indian Ocean, SW of Sumatra NE Atlantic (1135–2287 m) Opisthoteuthis Group 1 of O’Shea (1999) Only known from male specimens, no confirmed females Single male specimen only Opisthoteuthis hardyi Villanueva et al., 2002 . 277 Oceanography and Marine Biology: An Annual Review, 20 06, 44, 27 7-3 22 © R. N. Gibson, R. J. A. Atkinson, and J. D. M. Gordon, Editors Taylor & Francis TAXONOMY, ECOLOGY AND BEHAVIOUR. linearly, whist in the half-orange form they are grouped like segments of an orange. Opisthoteuthidae, Grimpoteuthidae and Cirroctopus and have the half-orange form, but the number and form of the lamellae. salivary gland in Cirrothauma, but the location of the single gland is different to Grimpoteuthis and incirrate octopods and is possibly not an analagous structure. The oesophagus, stomach and intestine