Polyandrocarpa colligata Sluiter, 1913

Kott, Patricia, 2005, Novel Australian Polyzoinae (Styelidae, Tunicata), Journal of Natural History 39 (32), pp. 2997-3011 : 3001-3002

Polyandrocarpa colligata Sluiter, 1913

( Figure 1B, C ) Polyandrocarpa colligata Sluiter 1913, p 68 . Polyandocarpa robusta Sluiter 1915, p 6 ; 1919, Taf. 1.

Distribution

New record: Queensland (Great Barrier Reef Seabed Biodiversity Survey, 16.705 ° S, 146.125 ° E, 33.9 m, QM G308758). Previously recorded: Aru I. and the Java Sea ( Sluiter 1913, 1915).

Description

The specimen is a tough, encrusting colony with small dorso-ventrally flattened zooids completely embedded in the test. The sessile apertures of each zooid open separately to the exterior. The body wall contains crowded vesicles forming a foamy layer lining the atrial cavity while the outer muscular layer of the body wall is thin and delicate. A vertical, sometimes sinuous, slit is on the dorsal tubercle. The branchial sac has four folds on each side with the internal longitudinal vessels arranged according to the following formula: E0(4)1(8)1(2)1(6)0DL. The gut forms an open and relatively short loop with the rectum turned anteriorly to form an angle with it. The pear-shaped stomach, with about 12 longitudinal folds and a short curved caecum, is in the middle third of the proximal limb of the gut loop. The outer curve of the gastric caecum is joined to the descending limb of the gut loop by a short ligament. A row of six to eight elongate polycarps is along each side of the mid-ventral line. Each polycarp consists of a paired row of male follicles (up to 18 in each row) beneath the ovarian tube. A few small endocarps are scattered on each side of the body wall.

Remarks

Like the present species, the subtropical P. colemani has embedded zooids and a foamy layer of vesicles in the body wall and closely resembles the present species. Polyandrocarpa colemani is distinguished from the present one by its massive colony with a network of vessels in the internal or basal test, a horizontal slit on the dorsal tubercle, a large flat-topped endocarp in the gut loop, longer stomach occupying at least three-quarters of the proximal limb of the gut loop and a thicker layer of muscles in the body wall. In the present species the gonads are in a single series along each side of the midventral line, while in P. colemani the polycarps are in one or two rows on each side at varying distances from the mid-ventral line to a single row along each side of the atrial aperture.

Figures

Figure 1. (A) Polyandrocarpa colemani (QM G308755): left and right pallial wall showing gut and gonads. (B, C) Polyandrocarpa colligata (QM G308758): (B) colony surface; (C) gut loop. (D–H) Oculinaria australis (SAM E3267): (D) portion of colony; (E) inner pallial body wall on right showing gonads; (F) inner pallial body wall on left showing gut and gonads; (G, H) siphonal spines. In (G), the open base of the spine in the centre of the light micrograph is showing; in all the other spines, only the hollow centres of the pointed tips are in focus. Scale bars: 1.0 mm (A); 2.0 mm (B, D–F); 0.2 mm (C); 0.05 mm (G, H).