Polyclinum campi, Fortaleza & Lotufo, 2018

Fortaleza, Maria Tarciana Vieira & Lotufo, Tito Monteiro Da Cruz, 2018, Polyclinidae (Ascidiacea: Aplousobranchia) from the Gulf of Mexico, collected during the “ Hourglass ” cruises (1965 - 1967), Zootaxa 4422 (4), pp. 519-536 : 530-531

Polyclinum campi sp. n.

( Figures 14 , 15 )

Etymology: The species is named after Dr. David K. Camp, eminent carcinologist who encouraged and enabled our study of the Hourglass Cruises ascidian collection.

Examined material: collected in 2/3/1967, 11/09/1967 and 11/5/1967, respectively; 27°37’N, 083°28’W, 36.6 m, specimens #EJ-67-162, # EJ-67-330 and # EJ-67-76.

Description: Flattened colonies with rounded edges, up to 9.1 cm long and average thickness of 0.6 cm. Small amounts of fine sand in the surface and in the broad attachment area of the colony. Tunic with brown coloration and of fleshy consistency. Zooids systems inconspicuous with the cloacal opening marked by a light elevation.

Zooids with average length of 4.99 mm, an elongated thorax sometimes reaching half of the total size of the animal. Abdomen and post-abdomen are very short (length range: thorax plus abdomen = 2.43–5.76 mm; postabdomen = 0.51–0.90 mm). Branchial siphon tubular, measuring 0.08–0.24 mm, with six sharp lobes. Atrial languet with variable length (0.32–2.88 mm) and a pointed tip or small teeth. Atrial opening rounded, small and not connected to the atrial languet, located at the level of the fifth stigmata row. Six to eleven thin muscular longitudinal bundles on each side of the body, from the branchial siphon to half the length of the thorax. Musculature also found in the atrial languet, which can vary between seven and nine fibers. Pharynx with 13–18 rows of stigmata and 14 small and round branchial papillae in the transversal vessels of each side of the thorax. The number of stigmata per row could not be counted. Esophagus narrow. Stomach large, rounded, and yellow. The size of the esophagus and stomach together are equal to the abdomen length. Intestine short, with two evident constrictions. Anus is bilobed, opening at the level of the ninth stigmata row. Post-abdomen short, sac-like, with a thin peduncle of around 0.10 x 0.40 mm. Gonads were well-developed in two of the specimens analyzed, the ovary located in the central portion of the post-abdomen along with approximately 30 testicular follicles. The posterior half of the thorax takes up to six embryos in a single series. Larvae with up to 0.63 mm and three adhesive papillae with thin and long peduncles, four elongated ampullae, ectodermal vesicles in the ventral region, and a tail wound ¾ way around the trunk.

Remarks. The genus Polyclinum currently has only three valid species recorded in the Western Atlantic, namely P. constellatum , P. aurantium , and P. molle ( Rocha et al., 2012a) . Polyclinum constellatum was described by Savingy (1816) based on specimens from Mauritius Islands, in the Indian Ocean. The original description, according to standards of the beginning of the 19th century, is very brief. Savigny states that zooids are organized in conspicuous systems, and each zooid has 14 stigmata rows in the pharynx. Van Name (1921) recorded P. constellatum for the first time in the Atlantic, later confirmed by Monniot (1983) after a comparison of specimens from Guadeloupe with the type material.

Polyclinum constellatum is found in the Indian Ocean and Tropical Atlantic. It is described as having variable sand content of the colony surface, zooids measuring 5–7 mm, 11–18 stigmata rows in the pharynx, 8–22 stigmata per row, 7 or 10 branchial papillae on each side of the pharynx, and larvae measuring 0.42–1.00 mm, with four pairs of ampullae ( Van Name, 1921; Van Name, 1945; Gravier, 1955; Millar, 1958; Millar, 1962; Millar, 1975; Monniot, 1983; Goodbody, 2003; Lotufo & Silva, 2005; Rocha & Costa, 2005). The present species is distinguished from P. constellatum mainly due to the larger number of branchial papillae and the larger number of ampullae in the larvae.

Descriptions of P. aurantium also mention many similar features with P. constellatum , including the presence of sand on the colony surface, zooids measuring 3.0– 7.5 mm, 10–16 stigmata rows with 9–17 stigmata per row, larvae measuring 0.43–0.50 with four or five pairs of ampullae ( Berrill, 1950; Gravier, 1955; Millar, 1953; Millar, 1956; Millar, 1966; Monniot, 1969; Monniot, 1974; Pèrés, 1949). The most distinctive feature of Polyclinum aurantium , when compared to the other species, is its larger number of larval ampullae.

Polyclinum molle was more recently described for the Brazilian coast ( Rocha & Costa, 2005) and bore some similarities with the species herein described, especially regarding the larval ampullae (12), zooid size, and muscle pattern. However, there are marked differences in the number of stigmata rows and papillae in the pharynx, and in the larvae regarding its size and location of the vesicles.

Considering all the similarities and differences, Polyclinum campi sp. n. is here described as a new species. Future surveys may determine whether it is still present in the waters of the Gulf of Mexico.

Figures

FIGURE 14. Polyclinum campi sp. n. Scales 1 cm—Preserved material in formalin. A—EJ-67-162; B—EJ-67-330; C—EJ-67- 76.

FIGURE 15. Polyclinum campi sp. n. A—larvae; B—zooid. Scale: A = 0,1 mm; B = 1 mm.