Family BUGULIDAE Gray, 1848

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Family BUGULIDAE Gray, 1848

Compiler and date details

July 2001 - Dr Philip Bock

Introduction

The family Bugulidae Gray (1848) was introduced for Bugula Oken. This name has had an unfortunate history, as it was once suppressed, together with the name Scruparia, but later validated by the International Commission on Zoological Nomenclature (Bulletin, 1970). The type species of Bugula is Bugula neritina (Linnaeus) which, curiously, lacks two of the characteristic features of the genus, marginal spines and birds-head avicularia. Included in the Bugulidae here are the genera Bugula, Caulibugula, Bugularia, Nordgaardia, Chalastobugula, Camptoplites, Klugella and Himantozoum. Fehlauer-Ale et al. (2015), following a molecular phylogenetic analysis of Bugula sensu lata, based on CO1 and RNA 16S genes, recognised four genera among currently recognised species: 'Bugula sensu stricto (30 species), Bugulina (24 species), Crisularia (23 species) and the monotypic Virididentula gen. n.'.

Colonies arise from an erect ancestrula (Hastings 1943; Ryland & Hayward 1977). Branches are often, but not universally, biserial. The autozooids often have a forked proximal end on the basal side, and the budding patterns were described by Harmer (1923). A very large number of species of Bugula have been described, and the genus is particularly well-represented in fouling faunas. B. neritina is probably the best-known fouling species, and has a pan-tropical to subtropical distribution. It is easily recognised by its shrubby, rust-red to purplish-brown colonies. Almost equally common, B. dentata has dark green colonies (Ryland 1965; Bock 1982; Ryland & Hayward 1992). These and other species which occur in Australia have been described by Gordon & Mawatari (1992). Generally, species are found in shallow water, but Hayward (1981) described B. decipiens from a depth of 4670 m in the southern Tasman Sea. Bugula neritina is also remarkable for the presence of a placenta-like structure associated with the ovicell, which is capable of transferring nutrients to the developing embryo (Woollacott & Zimmer 1975). It is also the first described source of bryostatin. Many other species have been recorded, generally from studies on fouling faunas, as well as B. neritinoides Hastings (1939) from Tasmania. However, still more are present in collections which have not been described.

The genus Caulibugula is distinguished by its colony structure. A series of long, branching, stalk kenozooids give rise by budding at intervals to fans or cones of biserial branches. There are seven species in the Australian fauna, five of which were originally described from Australia, often as species of Bugula or Stirparia. The genus has been discussed by Harmer (1926), Maturo (1966), and Fransen (1986). Hastings (1939) discussed the early astogeny and figured the occurrence, in some species, of large kenozooidal vesicles among the anchoring rhizoids at the base of the colonies. Most species are from shallow water, but C. inermis was illustrated from rock faces within deep tidal channels at 35 m, from the western Caroline Islands in the Pacific. It appears that the abundant fans of autozooids thrived in areas with strong currents (Colin & Arneson 1995).

The genus Bugularia was introduced for Carbasea dissimilis Busk (1852b) by Levinsen (1909). Colonies have strap-shaped branches with numerous zooidal series, and superficially resemble colonies of Flustra. Busk received his specimens from Hooker, who collected them from Tasmania. According to Bock (1982), B. dissimilis is fairly common in depths of 10-20 m from Victoria and Tasmania, but subsequent unpublished records show that its distribution extends to depths of more than 300 m, and is found as far west as Western Australia. Colonies are bushy, orange-brown and reach a height of 100 mm. Branches are about 8 mm wide, and each zooid has a small sessile avicularium proximally. The ovicells are prominent and smooth. A variety of epizooic bryozoans may be found encrusting the dorsal surfaces of the branches.

The genus Nordgaardia was introduced by Kluge (1962) for Arctic and Atlantic, deep-water species, and includes N. cornucopioides d'Hondt (1983) from Brazil. Specimens in the Museum of Victoria, from depths of 800 - 1000 m off Tasmania and eastern Victoria, have been identified as N. cornucopioides by Cook (2001), and the species has subsequently been reported by d'Hondt & Gordon (1996) from depths of 1160-1990 m off New Caledonia. The avicularia resemble those of some species of Cornucopina closely but the autozooids and ovicells are very like those of Camptoplites.

The genus Camptoplites Harmer (1923) was introduced for Bugula bicornis Busk (1884), from very deep water, 3658 m in the southern ocean, southwest of Australia, in a latitude of 53°S. Species are known from the tropics; for example C. lunatus Harmer (1926) occurs in the Indian Ocean and has recently been reported from New Caledonia by d'Hondt & Gordon (1996). However, the greatest number of species has been described from Antarctic and subantarctic waters. Hastings (1943) analysed the colony structure, ovicells, ancestrulae and avicularia of numerous species in great detail. Colonies are characterised by their avicularia, which have enormously elongated, uncalcified stalks. Avicularia may be long- or short-headed, and several types may occur in the one colony. The stalks move very slowly backwards and forwards, often bending, while the mandibles of the avicularian heads snap at irregular intervals. Their behavior has been described by Winston (1991). Hayward (1995) has given a key to Antarctic species and illustrated colonies and avicularia in great detail.

The genus Klugella was introduced by Hastings (1943) for Antarctic and subantarctic species originally assigned to Flustra by Busk (1884) and Kluge (1914). Colonies are flustrine, with marginal kenozooids, and the avicularia are sessile. The large ovicells have a largely membranous ectooecium. Hayward (1995) has pointed out that the genus Guillea d'Hondt & Redier (1977) from Kerguelen, is a junior synonym of Klugella.

Species of the usually deep-sea genus Himantozoum Harmer (1923) were described from shallower waters in the Antarctic by Hastings (1943). Colonies are less robust than those of Klugella and avicularia are absent. Hayward (1995) noted that the endemic H. antarcticum has been reported as one of the five dominant species in the bryozoan benthic community.

Diagnosis

Colonies erect, unjointed, weakly calcified, flexible, attached by rhizoids; rarely adnate uniserial. Zooids with extensive frontal membrane, with terminal or subterminal flap for extrusion of tentacles. Avicularia pedunculate, or absent in a few species; interzooecial avicularia in one species. Marginal or distal spines present in most species. Ovicells usually prominent, independent or hyperstomial; absent in a few species.