Placospongia ruetzleri van Soest, 2017

Ugalde, Diana, Fernandez, Julio C. C., Gómez, Patricia, Lôbo-Hajdu, Gisele & Simões, Nuno, 2021, An update on the diversity of marine sponges in the southern Gulf of Mexico coral reefs, Zootaxa 5031 (1), pp. 1-112 : 30-31

publication ID	https://doi.org/ 10.11646/zootaxa.5031.1.1
publication LSID	lsid:zoobank.org:pub:CC3A59D1-E09E-407E-93F4-4796FD3D7C19
persistent identifier	https://treatment.plazi.org/id/110587B3-4D16-480F-FF53-FED0493C3490
treatment provided by	Plazi
scientific name	Placospongia ruetzleri van Soest, 2017
status

Treatment

Placospongia ruetzleri van Soest, 2017 View in CoL

Tables 6, 7; Figs. 22 A–J View FIGURE 22 , 36E View FIGURE 36

Synonymy and references: Placospongia ruetzleri van Soest (2017: 173) .

Type locality. Guyana .

Material examined. CNPGG-2391, Hornos reef (19.19083°N, - 96.11777°W), 2.7 m depth, coll. Diana Ugalde, 27 August 2018.

Description. Encrusting habit fragmented in several parts ( Fig. 36E View FIGURE 36 ), the larger fragment 2.4 × 2.2 × 0.3 cm. Surface smooth among grooves. The grooves do not have contact lines between them; thus, no polygonal plates divide the cortex. Oscules and pores situated inside the grooves, up to 1 mm in diameter, slightly elevated from the groove. Brick orange color in vivo, light brown in ethanol. Consistency is hard and cartilaginous.

Skeleton. A thick crust of selenasters in the ectosomal region (1800 µm thick) and upright tracts of large tylostyles in choanosomal region, up to 180 µm thick ( Fig. 22A View FIGURE 22 ); small tylostyles next to tracts and scattered ( Fig. 22B View FIGURE 22 ). Other microsclere types scattered throughout the skeleton.

Spicules. Megascleres: Large tylostyles stout, straight and smooth ( Figs. 22C–D View FIGURE 22 ); 700– 803.3 (88.1)–950/12– 15.1 (23.3)–19.2 µm, tyle width 14– 17.6 (2.5)–21.5 µm. Small tylostyles similar to the previous category but smaller ( Figs. 22E View FIGURE 22 ); 185– 283 (79.3)–395/4.8– 7.9 (2.2)–12 µm, tyle width 7– 8.8 (1.7)–12 µm. Microscleres: Selenasters ( Fig. 22 F View FIGURE 22 – 1 View FIGURE 1 , G), 35– 62 (13.6)–80 µm in a larger diameter. Spirasters ( Fig. 22F View FIGURE 22 – 2 View FIGURE 2 , H–I), 12– 15.4 (2.5)–19.2 × 2.5– 3.8 (1.5)–7 µm (free of spines). Acanthomicrorhabds ( Fig. 22 F View FIGURE 22 – 3 View FIGURE 3 , J); 3.5– 6.1 (1.7)–9.8 × 1.5– 2.1 (0.4)–3 µm.

Distribution. Mexico (current record), Guyana ( van Soest 2017).

Remarks. This is the first record of the species after its original description, and the first record of P. ruetzleri in the GoM. Although our material has all spicule categories described by van Soest (2017), it has smaller sizes of spicules; viz. respectively, larger tylostyles 700–950/12–19.2 µm vs. 618–1158/11–19 µm; smaller tylostyles 185–395/4.8–12 µm vs. 324–479/6–11 µm; selenasters 35–80 µm vs. 66–82/51–66 µm; spirasters 12–19.2/2.5–7 µm vs. 16–26/2–4 µm; acanthomicrorhabds 3.5–9.8/1.5–3 µm vs. 7–14 /1–2 µm. Unfortunately, only one specimen was collected, and we cannot confirm if the smaller size of spicules is a common characteristic of the population of P. ruetzleri from the GoM or an interspecific morphologic variation. Another two species of Placospongia are recorded in the northern GoM: Placospongia carinata and P. melobesioides ( Rützler et al. 2009) . However, the two are originally from a different geographic location, the Indian Ocean and the Indo-Pacific region, respectively, making them not considered valid for the TNwA by van Soest (2017), including consistent differences concerning the west Atlantic P. carinata .

Order Haplosclerida Topsent, 1928