Tethya vacua, Austin, William C., Ott, Bruce S., Reiswig, Henry M., Romagosa, Paula & G, Neil, 2014

Austin, William C., Ott, Bruce S., Reiswig, Henry M., Romagosa, Paula & G, Neil, 2014, Taxonomic review of Hadromerida (Porifera, Demospongiae) from British Columbia, Canada, and adjacent waters, with the description of nine new species, Zootaxa 3823 (1), pp. 1-84 : 76-78

Tethya vacua n. sp.

Fig. 30 A–K

Etymology. The species name, vacua , refers to the empty vacuolated cortex in the specimens.

Synonymy. Tethya californiana of Sarà & Corierro, 1993, in part.

Material examined. Holotype CASIZ 0 53441, (Cal. 3) Channel Islands, southern California, (34° 0′N, 120° 0.1′W), 9 m depth, Dec. 24, 1981, coll. France & Efford. Paratype 1, = CASIZ 1842878; Paratype 2, RBCM 011- 00038-001 = CASIZ 0 53441. For DNA sequencing CASIZ 184729; [KML 1132] = CASIZ 0 53441.

Description. Macroscopic features. ( Fig. 30 A). Hemispherical, holotype 6.3 cm long diam., 5.8 cm short diam by 3.2 mm in height; four other specimens in same lot with diam. ranging from 3.1 cm to 5.2 cm by 3.2 to 3.9 cm in height; surface with smooth fungiform tubercles ( Fig. 30 A); 1–2 bundles of megascleres radiate out to each tubercle. Colour in life is reddish brown (morocco on museum label).

Microscopic features. ( Fig. 30 B) Cortex 1–3 mm thick; the outer cortex filled with elongate vacuoles 100–200 µm long by about 50 µm wide; the inner cortex filled with larger vacuoles 250 µm–350 µm long x 10 –200 µm wide; outer choanosome with vacuoles approximately 800 µm long x 300 µm wide. Without serial sections, cannot exclude likelihood that some of vacuoles are in fact cross sections of canals.

Spicules. (Table 14, column A; Fig. 30 C–K). Main megascleres making up the fascicules primarily anisostrongyles with few strongyloxeas; interstitial auxillary megascleres are styles ( Fig. 30 C–G); megasters ( Fig. 30 H, I; Fig 26 C; Table 14, column A) have an R/C value of 0.6–(0.9)– 1.1 in the cortex and 0.8–(1.0)– 1.3 in the choanosome. They are present but not abundant in the cortex. Euasters are acanthostrongylasters and rare oxysphaerasters which have thin rays and small centrum with an R/C of 2.5.

Remarks. We commented at the beginning of remarks under T. californiana that our specimens (Cal. 3 = CASIZ 053441) were collected by the same people on the same day, at similar depths and in nearly the same locality as Cal. 1 and 2 described by Sarà & Corriero (1993). A thick section of Cal. 3 ( Fig. 30 B) appears similar to the illustration by Sarà & Corriero ( Fig. 28 ) (based on Cal. 1 and 2) in having a highly vacuolated cortex with a peripheral layer of smaller vacuoles equivalent to those they termed alveolae. The vacuoles are more elongate in Cal. 3. This could be the result of differential contraction of the specimen. The following characters are similar to identical between Channel I. Cal. 3 and Channel I. Cal. 1 &2: sizes of the megascleres (Table 14, column A and Table 16, column B); dominance of anisostrongyles over strongyloxeas; styles predominant auxillary macroscleres; the R/C values of the megasters (Table 14, column A and Table 16, column B); acanthostrongylasters and thin armed oxyasters.

There is one apparent difference between Cal. 1 & 2 as described by Sarà & Corriero (1993) and Cal. 3 as observed by us. We were unable to find any spiny oxyasters (acanthoxyasters) while Sarà & Corriero (1993) drawings depicted fine spines on 3 of 4 oxyasters (their Fig. 4 D). They also referred to spined rays in both strongylasters and oxyasters. However, the one SEM they showed of an oxyaster does not have visible spines. We find that the presence or absence of spines can only be determined on SEMs in our material, and we only found one SEM of an oxyaster ( Fig. 30 J). It has no spines. More material is needed to resolve this apparent difference.

If indeed Cal. 1 and 3 represent the same species, and this species is not T. californiana , (as concluded above) then this species requires a name. It is not synonymous with any of the eastern Pacific or NW Pacific species based on the predominance of anisostrongyles or other differences in megascleres (as described in more detail under T. californiana ).

Sarà et al. (2001) recorded what they called T. californiana (sensu Sarà & Corriero) from the Gulf of California. However, the specimens had only strongyloxeas not any anisostrongyles.

Conclusions. The material from southern California (Cal. 1, 2 and 3) represents a new species T. vacua n. sp. which is not synonymous with any other described species from the eastern Pacific or the NW Pacific.

Bathymetric range. 9 m depth.

Geographic distribution. Channel Islands, California ( USA).

Figures

FIGURE 4. Cliona lobata Hancock, 1849. A, tylostyle, scale bar 50 µm; B, tylote head; C, multilobed head; D, subterminal tyle; E, stylote head with a subterminal swelling, scale bar 20 µm; F, small spiraster, scale bar 40 µm; G – I, large spiraster, scale bar 40 µm.

FIGURE 26. Tethya californiana de Laubenfels, 1932. Cross sections of cortex; A, Winter Hbr, Hall Bank, BC, scale bar 3 mm; B, McBride Bay, Tahsis Narrows, BC, scale bar 3 mm; C, RMMU I- 2078, San Jose Creek, Pt. Lobos, Carmel, CA, scale bar 0.5 mm; D, CASIZ 0 67731, Hopkins Marine Station, Pacific Grove, CA, scale bar 2 mm.

FIGURE 28. Relationship of cold temperate NE Pacific Tethya species megaster R / Cs (ratio of megaster spine length to centrum diameter) to latitude.

FIGURE 30. Tethya vacua n. sp. A, Holotype (CASIZ 053441), scale bar 1 cm; B, cross section of holotype, smaller vacuoles of outer cortex (above) and larger vacuoles of inner cortex below; C, anisostrongyle, scale bar 500 µm; D, head of anisostrongyle, scale bar 50 µm; E, foot of anisostrongyle, scale bar 50 µm; F, head of strongyloxea, scale bar 30 µm; G, foot of strongyloxea, scale bar 30 µm; H, megaster scale bar 50 µm; I, megaster scale bar 40 µm; J, oxysphaeraster, scale bar 10 µm; K, acanthostrongylaster, scale bar 10 µm.