Tethytimea authia de Laubenfels, 1930

Turner, Thomas L., 2020, The order Tethyida (Porifera) in California: taxonomy, systematics, and the first member of the family Hemiasterellidae in the Eastern Pacific, Zootaxa 4861 (2), pp. 211-231 : 222-224

Tethytimea authia de Laubenfels, 1930 (comb. nov.)

Synonymy.

Timea authia de Laubenfels, 1930

Material Examined. CASIZ 235111 , Perkin's Reef, Monterey CA (36.62920, -121.92031), 11/24/19 . CASIZ 235110 , Carpinteria Reef, Santa Barbara CA (34.39163, -119.54169), 7/31/19 . TLT 364 , Saddleback Ridge, Santa Cruz Island CA (34.03817, -119.52470), 10/18/19 .

Description. Macroscopic features. An encrusting sponge; samples vary from 0.5–2.0 mm thick. Color yellow/orange when alive (figure 5). The surface is sculpted by gutters in situ, but the sponge contracts when collected, and gutters are no longer visible. Scattered, mushroom-like papillae present on surface, approximately 1–3 mm in diameter. No other sponges were located with these features in the current survey: it is therefore possible that this species can be identified from field photos, at least within the Southern California portion of its range. Note that these characters are difficult to see in the field, and more apparent in macro photos.

Spicules. Megascleres are tylostyles with oval heads, styles with an enlarged band near the head, and simple, unadorned styles (figure 6). Microscleres are asters. The most common aster has thick, non-tapering rays with enlarged tips, usually with spines at the tips (tylasters). Others have cone-shaped rays ending in sharp tips (oxyspherasters). Intermediates are also found, with tapering rays that are fairly cone-shaped, but ending in enlarged tips with spines. Spicule measurements are shown in table 2, and compared to published data ( Carballo and Cruz-Barraza 2006). Carballo and Cruz-Barraza (2006) reanalyzed the holotype and used SEM to provide more detail regarding spicule shape. Data from my three samples are entirely consistent with their data, qualitatively and quantitatively.

Tethytimea are described as having two size classes of asters: larger "megasters" and smaller "micrasters". Timea are described as having only "asters". I quantified the size distribution of asters to determine whether there was more than one size class (figure 7). One sample (TLT364) seemed to have two size classes, with "megasters" 13–30 μm and "micrasters" 3–7 μm (though 2% of asters were intermediate). The other two sponges had two modes, but the distributions of the size classes were overlapping. I used Hardigan's Diptest to test for unimodality, which was rejected for all three samples (p<0.0001 for all). The larger sized asters included both oxyspherasters and tylasters, with tylasters more common. Only tylasters were seen among the smallest asters.

Microscopic features. Perpendicular sections show tissue packed with asters (figure 6). Megascleres (styles/ tylostyles) are found in projecting bundles, tips up, that pierce the surface of the sponge. Bundles fan-out as they rise through the sponge, resulting in bouquets of spicules at the surface. Other megascleres are found parallel to the substrate in the lower third of the tissue section.

Geographic distribution. The range of this species in the United States was previously described as Southern California only ( Lee et al. 2007). This range is here extended North to Monterey Bay in Central California. To the South, samples from as far away as Chile have been assigned to this species, though no molecular data is yet available for confirmation ( Carballo and Cruz-Barraza 2006, Desqueyroux-Faúndez 1972). The depth range of the species was previously described as "intertidal to deep water" ( Lee et al. 2007). All three samples collected in the current work were from the shallow subtidal, 3.5–11 m in depth. It was not found in the intertidal, but sampling in the intertidal was very limited. The holotype was collected from the Southern California intertidal in 1930 ( de Laubenfels 1932).

Remarks. Genetic data strongly support membership for this species in the Tethyidae and not the Timeidae . As discussed in the phylogentic results, it is currently difficult to ascertain the differences between Timea and Tethyatimea, because the species membership of each genus is incompletely ascertained. One proposed distinction has been the presence of size classes of spicules among the Tethytimea ( Cruz-Barraza et al. 2017, Sará 2002). I find that samples of T. authia have a bimodal distribution of aster sizes, consistent with this diagnosis. The overlapping size ranges may partially explain why this sponge has not been diagnosed as a Tethyatimea in the past.