Family CATENICELLIDAE Busk, 1852

Museums

Museum list

Regional Maps

Family CATENICELLIDAE Busk, 1852

Compiler and date details

July 2001 - Dr Philip Bock

Introduction

The family Catenicellidae was introduced by Busk (1852), and the validity of the name, rather than the name Vittaticellidae, which Harmer (1957) introduced, has been fully discussed and established by Gordon (1984). Busk (1852) remarked 'the genus' (ie. Catenicella ) 'may be regarded as characteristic of the Australian seas'. Certainly, some of the earliest records, such as that of Pterocella vesiculosa (Lamarck 1816), are from Australia, and of the 25 or so genera currently referred to the family, at least 16 have either an Australian Tertiary or Recent type species, or have a principally Australian distribution. Over 50 nominal species have been described as occurring in Australian waters. Generally species are found in warm, shallow conditions, often growing on algae or hydroids (Bock, 1982), and predominantly from the southern hemisphere. One deeper-water genus is known (Gordon & d'Hondt 1985). Gordon & Braga (1994) have included three subfamilies in the Catenicellidae: the Catenicellinae, the Ditaxiporinae and the Vasignyellinae. The Vasignyellinae is here regarded as a subfamily of the Ditaxiporinidae. In spite of its taxonomic diversity, the Catenicellidae has a number of consistent and distinctive characteristics. Colonies are erect and nodal, arising from a single, semi-erect ancestrular complex and anchored by rhizoids (Wass 1983). With very few exceptions, internodes consist of one to three autozooids only, each internode separated by cuticular joints, and all facing in the same direction. Colonies are profusely branched, the bifurcations following a distinct, often specific or generic pattern (Wass 1977). In all cases, branches alternate from right to left of the primary branch. Secondary and tertiary branches are always budded from the same side as the original first branch. Branches of many species curve frontally, producing feathery tufts, which often are brilliantly coloured. Pigments range from pink, green and bright yellow, to purple, red, orange and brown (Maplestone 1882). Bock (1982), Wass (1984) and Colin & Arneson (1995) have all illustrated colonies in colour. Colonies may range in height from 25 - 80 mm, reaching 120 mm in Orthoscuticella ventricosa, according to Bock (1982). Wass (1984) gives a maximum diameter of 300 mm. Unispecific and multispecific settlement of colonies occurs, they are often abundant, and may be part of a fouling fauna. Gordon & Mawatari (1992) listed 8 species which were found fouling lobster pots in New Zealand. Catenicellids often colonise themselves (Wass 1983), and colonies are often the substratum for other species of bryozoans and other animals. The flexibility of the cuticular joints and the well-developed, anchoring rhizoid systems allow colonies to inhabit environments with moderate sedimentation and strong current action. Although the calcification of the zooids is thin, colonies are robust, and isolated zooids are often preserved in both Recent and fossil assemblages in very large numbers, and may dominate the finest fractions of the sediment.

Autozooids are tubular proximally and curved basally, with a subtriangular outline, being expanded distally, often with an avicularium on each 'shoulder'. Calcification is thin and generally smooth, although the basal surface may be finely ridged in some species. The orifice is sub-terminal, generally D-shaped or slightly curved proximally, although a few species have a distinct sinus. In many species, the orifice has paired condyles. The frontal shield consists of a gymnocyst arising from the cuticular node and expanding to surround a suboral and central region which may be costate, and often has large costal windows around the periphery. Those costae which may form the proximal part of the orifice sometimes have pelmatidia terminally, but in many genera are vestigial. One of the most distinctive features of the family is the presence in the lateral gymnocyst of a special kind of pore chamber. Essentially, there are four pairs of these, but the more proximal pair are often fused. Sometimes the pore chambers form a lateral groove, with a line of pores in its basal calcification. This is known as a vitta (plural vittae), and is characteristic of genera which have almost completely gymnocystal frontal shield. The pore chambers are covered frontally with cuticle, and may be extended laterally and distally to form 'alae' or wing-like kenozooids with a cuticular frontal wall.

The remarkable morphology of the autozooids in the Catenicellidae has attracted its own, often complicated, terminology. Principal works defining these terms are those of Busk (1852), Maplestone (1898, 1899), Levinsen (1909), Stach (1933, 1934, 1935b), Harmer (1957), Wass (1977) and Gordon (1984, 1989). Colony internodes usually have one to three zooids, budded distally or distolaterally. The unizooidal internodes are known as: a globulus, singlet, singleton or unizooidal segment. Bizooidal and trizooidal internodes are known as a biglobulus and triglobulus, etc. The lateral series of pore chambers are known alternatively as chambers or compartments. From the distal end these are termed suprascapular or supravicularian; scapular or avicularian; distal infrascapular or distal infravicularian; and proximal infrascapular or pedal. The second pair of pore chambers are usually developed as the whole or part of an avicularian subrostral chamber and are well calcified. The avicularian rostrum may be hooked and usually has a bar. Enlarged avicularia are part of the budding pattern in some species. The third and fourth pore chambers are frequently combined to form either an elongated vitta, or expanded laterally to form shallow areas of cryptocyst with one or more septular pores in the calcified wall. The frontal walls of these areas are cuticular. In some species the costal windows are lined by cryptocyst, and the frontal part of the underlying ascus may also be calcified, and visible between the costae.

The development of the ascus and associated muscles has been described by Harmer (1902), and in detail by Banta & Wass (1979). Briefly, species with principally costate frontal shields tend to have an ascus formed by a frontal membrane, whereas those with gymnocystal shields tend to have a type of lepralioid development. Intermediate states of these developmental series occur. The number of tentacles was given for some species by Maplestone (1882) and ranges from 12 to 18. Rhizoids develop from a pore plate in the basal wall (Wass 1983) or from one of the lateral pore chambers. They grow backwards down the branches, eventually forming an anchoring stalk.

Ovicells may be budded as part of a bizooidal or trizooidal complex, and may be distal or distolateral in origin. The alternative, terminal type of ovicell consists of an internode composed of a maternal zooid and ovicell, with no further budding of any joint or internodes. However, the ovicell itself may have a distal kenozooid, or even a very small zooid budded from its distal wall (Wass & Banta 1981). Both Levinsen (1909) and Wass & Banta (1981) illustrated the origins of the ovicell as a kenozooid budded distally to the maternal zooid. The basal exterior wall of the maternal zooid forms the ectooecium, whereas the distal interior wall forms the entooecium. A pore communicates between the maternal zooid and the ovicell capsule. Frontally, the ectooecium is often deficient, forming distinct patterns of entooecium which may be specific. Enlarged orifices of maternal zooid and ovicell complexes occur in many species.

The wealth of correlated character states present in budding patterns, composition of internodes and frontal shield morphology, together with avicularian and ovicell complex characteristics, means that most of the genera are easily defined. Intermediate conditions of states occur in some species. Nearly all genera have unizooidal to bizooidal internodes, which are bizooidal at a bifurcation. Only Calpidium has regularly bizooidal to trizooidal internodes. Multizooidal internodes occur in some species of Catenicella and include more than one successive ovicell complex. Pterocella, Costaticella and Scuticella have costate frontal shields with costal windows, whereas the shields in Cribricellina, Orthoscuticella, Calpidium and Strongylopora have vestigial or no costae but either large, or numerous small, costal windows. In some species of Orthoscuticella and in Strophipora the pore chambers are so extensive that they occupy almost all the frontal shield, forming shallow expanses with one or more pores in the cryptocystal wall, and leaving a small ridge of central gymnocyst. In contrast, the frontal shield in Catenicella, Scalicella and Cornuticella is principally gymnocyst, with long, narrow paired vittae laterally. An ascopore is present in certain species of Orthoscuticella, Claviporella, Paracribricellina and Strophipora. Subterminal ovicells occur in Catenicella, Scalicella, Pterocella, Claviporella, Cornuticella and Strongylopora, and terminal ovicells in Orthoscuticella, Costaticella, Cribricellina, Scuticella and Calpidium. The deep-water genus Talivittaticella Gordon &d'Hondt (1985) has not been recorded from Australia at present, but is known from New Zealand, southern South America, and from Antarctica (Gordon & d'Hondt 1985; Hayward 1995). However, specimens have been collected from depths of 800-1000 m. off the east coast of Victoria.

About 56 species have been recorded from Australian waters: the majority of these are endemic, but some species are widely distributed, such as Catenicella elegans. It is believed that detailed investigation will show that a few of these species may be synonyms of other species, and that relatively few species remain undescribed.

The internodes are frequently preserved as fossils, and Costaticella and Strophipora have fossil type species described by MacGillivray (1895). Other species were discussed by Maplestone (1898, 1899) and Stach (1933, 1934, 1935b) who summarised the generic characters (1933a). The Catenicellidae has a long and widely distributed fossil record, extending from the Maastrichtian of Jamaica (Gordon & Braga 1994), and the Upper Paleocene of Europe to the Eocene of North America, Europe and the Pacific. Gordon & Braga remarked that the Catenicellidae presumably diversified from the Cribrilinidae sensu lato during the Senonian (uppermost Cretaceous).

Diagnosis

Colonies erect, flexible, jointed, anchored by rhizoids; internodes normally of one to three autozooids, with cuticular connecting tubes. Zooid calcification typically smooth gymnocyst; frontal area may include a costal field, a group of windows, or be imperforate. Marginal kenozooids, or pore-chambers, usually with a window over a calcified gymnocyst with communication pores, sometimes elongate (vittae). Distal kenozooids may be elongate and pointed. Orifice D-shaped, or with proximal margin concave or sinuate. Central frontal pore opening to compensation space present in few species. Avicularia single or paired, disto-lateral, or absent. Brooding zooids with enlarged ovicells developed in several ways; either at a branch termination, in line with an autozooid, or as one of a group of two or three autozooids.