BULLETIN OF MARINE SCIENCE, 55(1): 176-192, 1994 CORAL REEF PAPER THE TROPICAL WESTERN ATLANTIC PEROPHORIDAE (ASCIDIACEA): I. THE GENUS PEROPHORA Ivan Goodbody ABSTRACT Five species in the genus Perophora occur in the tropical western Atlantic, distinguished by morphology and habitat requirements. P. viridis and P, regina have four rows of stigmata and longitudinally oriented mantle muscles; P. multiclathrata. P. bennudensis and P. car- penteria n. sp. have five rows of stigmata and transversely oriented mantle muscles. Specific differences in the arrangement of the mantle muscles are considered to be of taxonomic importance. P. bennudensis is considered to be a valid species and not a synonym of P. multiclathrata. In the absence of a designated Type an original specimen of P. bennudensis from the type locality is declared to be the Neotype. P. viridis is thc most cosmopolitan of Caribbean species while P. regina and P. bennudensis are restricted to areas of fairly strong flowing currents in mangrove channels. P. multiclathrata is characteristic of quiet sheltered environments and P. carpenteria flourishes in shallow water with moderately agitated water flow. The family Perophoridae is primarily a warm water group of ascidians although a few species, notably in the genus Perophora, penetrate into temperate and high latitudes. The characteristic feature of the family is a system of stolons from which individual zooids arise at intervals to form colonies consisting of either clusters of zooids (e.g., Ecteinascidia turbinata Herdman, 1880), creeping mats in which the individual zooids in the colony are more widely spaced (e.g., Perophora viridis Verrill, 1871) or erect branching colonies in Perophora namei Hartmeyer and Michaelsen, 1928 from the Pacific, Unlike some other colonial ascidians (e.g., Polyclinum, Eudistoma) the zooids of the Perophoridae are always separate from one another and only connected by the system of stolons. This paper is the first in an intended series which examines the taxonomy and biology of the tropical western Atlantic species in the family, The family contains only two genera, Perophora Wiegmann, 1835 and Ectei- nascidia Herdman, 1880, In general the zooids of Ecteinascidia are larger than those of Perophora but overlap in size occurs. The distinction between the two genera (Fig, 1) is based primarily on the number of rows of stigmata in the branchial sac, the organization of the alimentary canal and the form of the testis (Kott, 1985), Most Perophora species have only four or five rows of stigmata, but one Pacific species Perophora multistigmata Kott, 1952 is exceptional in having eight rows. In those cases where five rows of stigmata occur some stigmata span the width of rows one and two indicating that the additional row is split off from the original first row and hence four is the primary number of rows. In Ecteinascidia there are always more than eight rows of stigmata and usually between twelve and twenty. In Perophora the gut loop is horizontal and the rectum short; Ecteinascidia has a more open curved gut loop and a long rectum. The testis in Ecteinascidia usually forms an open crescent of pyriform lobes arranged inside the loop of the gut and discharging by a series of ducts to a single sperm duct or vas deferens. In Perophora the testis seldom has more than four lobes, often only one, situated in the gut loop. Mantle musculature has received little attention as a character of importance in ascidian taxonomy in spite of the fact that it has considerable functional signifi- cance. Branchial pressure is controlled by the activity of the siphons and the 176 GOODBODY: WESTERN ATLANTIC PEROPHORIDAE 177 .' ... " - .' '" .. -- .". t A Figure I. Comparison of typical Ecteinascidia (E. turbinata Herdman) [A] with Perophora (P. ber- mudensis Berrill) [B] showing the more open gut loop, larger number of rows of stigmata and large number of pyriform testis lobes in Ecteinascidia. For clarity the mantle musculature is not shown. Scale A: 0.5 em, B: 1.0 mm. mantle musculature (Goodbody and Trueman, 1969; Goodbody, 1974) and hence feeding activity must also be influenced by these muscles. Although taxonomic significance is probably more important at the species, than the generic, level it is to be noted that in Ecteinascidia there are usually broad areas of transverse fibers on the mantle, particularly in the anterior end, while the arrangement of fibers in Perophora is usually more discrete and involves fewer fibers. This is discussed further below. This paper deals exclusively with the species of Perophora occurring in the tropical western Atlantic, viz: Perophora viridis Verrill, 1871, Perophora regina Goodbody and Cole, 1987, Perophora bermudensis Berrill, 1932, Perophora mul- ticlathrata (Sluiter, 1904) and Perophora carpenteria n. sp. These five species belong to two distinct groups characterized by the number of rows of stigmata and the arrangement of mantle musculature. P. viridis and P. regina have only four rows of stigmata and the mantle musculature is primarily of longitudinal origin. The remaining three species have five rows of stigmata, the most anterior row being confluent with the second so that some stigmata extend through both 178 BULLETIN OF MARINE SCIENCE, VOL. 55, NO. I, 1994 Figurc 2. Thc arrangement of mantle musculature in Perophora viridis (from Goodbody and Cole, ]987). Scale ].0 mm. rows; these species have mantle musculature which is primarily of transverse origin imparting a circular type contraction to the body. In recent taxonomic literature P. bermudensis has been treated as a synonym of P. formosana (Oka, 1931) (Monniot, 1983) which is itself now considered a synonym of P. multiclathrata (Nishikawa, 1984; Kott, 1985). In this paper it will be shown that P. bermudensis is quite distinct from P. multiclathrata not only in morphology but also in its ecology; the morphological distinctiveness was clearly recognized by Arnback-Christie-Linde (1935) (see below). MATERIAL The material on which this paper is based has bcen collccted in Jamaica, Belizc, Bermuda, Bonaire and Puerto Rico. This has been supplemented by examination of additional museum materia] as follows: a colony of P. bermudensis collected by Berrill in ]932 (Rijksmuseum, Stockholm, #] 537); a syntype of P. formosana Oka, ]931 (Imperial Househo]d, Tokyo, #27); Sluiter's type specimen of P. multiclathrata (Zoo]ogica] Museum, Amsterdam, TU 558-4); a specimen of P. multiclathrata from Puerto Rico collected by P. Wagenaar Hummelinck in 1963 (ZMA, TU 1640); several specimens of P. multiclathrata from Lac of Bonaire, Netherlands Antilles, collected by P. Wagenaar Hummelinck in ]967 (ZMA, TV 2049; TV 4020) and specimens of P. multiclathrata from the collections of the Queens]and Museum representing material from Wistari Reef, Queensland (QH 4272), Heron Island (GH 3819), Norfo]k Is]and (QH 4678), Fiji (G ]2468) and the Philippine Islands (GH 444). GOODBODY: WESTERN ATLANTIC PEROPHORIDAE 179 Perophora viridis Verrill, 1871 Figure 2 Perophora viridis Verrill, 1871 p. 359. Perophora viridis Van Name, 1945 p. 165. Although many authors make reference to Perophora viridis there are few comprehensive accounts and only that of Van Name (1945) is in any way com- plete. The account which follows amplifies and modifies Van Name's description. The test is thin and transparent and the zooid frequently looks green; this is due to blood cells circulating in the underlying mantle and is not a function of the test. One of the most characteristic features of P. viridis which distinguishes it from other Caribbean members of the genus, but allies it closely with the European Perophora listeri Forbes and Hanly, 1848, is the arrangement of the mantle musculature. On each side of the zooid there are about 12 short longitu- dinal muscles arising anteriorly and extending about one quarter the length of the zooid. These muscles have their origin from an anastomosis of fibers arising on the two siphons and on an oval area of tissue between the siphons, referred to by Goodbody and Cole (1987) as the siphonal plate. The action of these muscles on contraction is such as to pull in the anterior end of the zooid like a diaphragm and to pull the siphons down into the now depressed siphonal plate. Small circular muscles occur on the siphons but nowhere else. The branchial sac has four rows of stigmata usually with only 17 or 18 stigmata per row, the most dorsal of which is often reduced in size. Van Name (1945) reported over 20 stigmata per row which is probably a function of slightly larger zooids in colder North American waters. On the internal face of the branchial sac small papillae arise from the transverse vessels running between the rows of stigmata, usually eight on each vessel so that there are two stigmata between each papilla. The papillae arise from a membranous triangular base and some, but not all, bifurcate to give longitudinal processes anteriorly and posteriorly but these seldom unite to form internal longitudinal vessels. In general the most anterior transverse vessel has the best developed papillae and the posterior vessel may have no such development. In those cases where longitudinal processes develop, a small extension of the papilla inwards into the branchial sac forms a secondary papilla as has been described in P. regina by Goodbody and Cole (1987). The dorsal lamina is a thin membrane from which three languets hang down into the branchial sac, one level with each of the transverse vessels. The opening of the neural gland appears as a simple oval aperture. Both the branchial and atrial siphons have six or more prominent pointed lobes and there are normally 20 branchial tentacles, 10 large and 10 small, but this number may vary and the small tentacles may sometimes be rudimentary. The horizontal gut loop, situated on the left side, is simple and has a small rounded stomach and usually a bilobed anus.