Scopalina goletensis, Turner, 2021

Turner, Thomas L., 2021, Four new Scopalina from Southern California: the first Scopalinida (Porifera Demospongiae) from the temperate Eastern Pacific, Zootaxa 4970 (2), pp. 353-371 : 365-366

Scopalina goletensis sp. nov.

( Fig. 5 )

Material examined. Holotype: ( CASIZ 235470 ) Elwood Reef , Santa Barbara, California, USA (34.41775, - 119.90150), 12 m depth, 10/23/19.

Etymology. Named for the town of Goleta that is onshore from the location where the sponge was discovered.

Morphology. Encrusting, 1.0– 1.2 mm thick, approximately 2.5 cm across (figure 5). Firm and incompressible. Surface hispid due to dense profusion of protruding styles. Distinct ectosome not apparent. Beige / cream colored in nature; retained the same color when preserved in ethanol. Surface traced by varicose, translucent channels; pores (approximately 200–300 μm diameter) abundant and uniformly distributed.

Skeleton. Basal mat of spongin cored with sediment. Vertical extensions of spongin 10–600 μm high arise from this mat: none of these were cored with sediment, but loose sediment was abundant throughout the sponge. Heads of some spicules are embedded singly, directly in the basal mat of spongin, but most are embedded as tiered bundles in the vertical extensions of spongin.

Spicules. Styles only, usually slightly bent towards the head end, thickest at the head and tapered to a point. Some spicule tips are “telescoping” (width decreasing in a step-wise fashion) at the pointed end. Spicules averaged 687 μm in length (N=37, range 388–801 μm); 15 μm in width (N=37, range 6–21).

Distribution and habitat. Only a single individual has been found, on a vertical ledge at 12 m depth, at Elwood Reef, in Santa Barbara, California. Habitat was rocky reef with abundant bryozoan, sponge, and anthozoan cover, under a year-round kelp canopy. Considerable search effort at Elwood Reef and nearby locations failed to locate additional individuals, so this species is likely to be rare in this area.

Remarks. This species is most similar to S. kuyamu , but is morphologically and genetically distinct, as detailed in the S. kuyamu remarks. The spicule dimensions are similar to several species from other regions ( S. azurea ( Bibiloni, 1993) , S. blanensis ( Blanquer & Uriz, 2008) , S. hispida ( Hechtel, 1965)) , though none of these others is known to have spicules as thick. All but S. azurea can also be excluded based on the available genetic data ( Figs. 1 , 2 ). Conspecificity with S. azurea is unlikely based on geographic isolation, color, and spicular architecture ( Bibiloni 1993).

It does not seem likely that this species can be identified from field photos alone, though it is difficult to say if there are reliable field marks until more individuals are found.

Figures

FIGURE 1. Gene tree at the cox1 mitochondrial locus. Bootstrap values are shown for nodes with> 50% support; nodes with <50% support are collapsed. Genbank accession numbers are shown; those beginning with M, shown in bold, are new. Scale bar indicates substitutions per site. Root placement based on Redmond et al. (2013).

FIGURE 2. Gene tree at the large ribosomal subunit (28S). Bootstrap values are shown for nodes with> 50% support; nodes with <50% support are collapsed. Genbank accession numbers are shown; those beginning with MT, in bold, are new. Scale bar indicates substitutions per site. Root placement based on Redmond et al. (2013).

FIGURE 5. Scopalina goletensis sp. nov.. All images from holotype. A: field photo. B: Skeletal architecture, showing basal plate cored with sediment. C, D spicules.