Thoosa mismalolli Carballo, Cruz Barraza & Gómez, 2004

Pacheco, Cristian, Carballo, José Luis, Cortés, Jorge, Segovia, Johanna & Trejo, Alejandra, 2018, Excavating sponges from the Pacific of Central America, descriptions and a faunistic record, Zootaxa 4370 (5), pp. 451-491 : 481-482

Thoosa mismalolli Carballo, Cruz Barraza & Gómez, 2004

Material examined. MZUCR.182: Isla del Caño , 4 m, 1984, coll. Jorge Cortés Núñez, det. Cristian Pacheco Solano . MZUCR.380: Isla del Caño , 10 m, 12. II.2011, coll. and det. Cristian Pacheco Solano .

External morphology. Endolithic sponge in alpha morphology. Material not sufficient to allow reliable description of external characters.

Excavation. Fused galleries with average diameter of 2 mm. Erosion scars with diameters between 29 and 56 µm. Inner surface of scars irregular, with pronounced ridges and radial structures ( Fig. 34), providing additional information to distinguish between Thoosa and Cliona ( Calcinai et al. 2004) .

Spicules. Megascleres tylostyles and oxeas, microscleres oxyaster derivates and amphiasters ( Fig. 35). Tylostyles scarce, not measured. Oxeas centrotylote, with length average of 57.4 µm (σ=7.7). Thick amphiasters with 14 nodules, 2 at each apex and 6 per verticil, in alternating arrangement. Nodules microspined. Nodulose amphiaster average dimensions of 21,3 µm (σ=2.3) x 14,1 µm (σ=2.4). Thinner amphiasters with fourteen nodules in arrangement as described above, irregular endings or smooth, with average dimensions of 17,1 (σ=3.0) x 10,2 µm (σ=2.4). Biradiate, triradiate or tetraradiate oxyasters, some with microspination, length average of 50,5 µm (σ=7.2).

Ecology. The specimens were found in dead pocilloporid corals at 10 m depth.

Distribution and previous records. The species was described from Mexico ( Carballo et al. 2004), and Guzmán (1988) probably from Costa Rica (see Remarks), which our study confirmed ( Fig. 36). Todate Costa Rica was the only site in Central America where this species was detected.

Remarks. The three Thoosa species presently known in the ETP— T. calpulli , T. mismalolli and Thoose purpurea Cruz-Barraza et al., 2011 —are quite easy to distinguish by comparing the most common spicule, the main amphiaster ( Fig. 31, 35 and Fig. 9A in Cruz-Barraza et al. 2011). However, all three species were only recently described and any findings before 2004 relied on the then existing literature. Guzmán (1988) sampled a Thoosa species from Costa Rica and identified it as Thoosa mollis Volz 1939 . However, the distribution of this species is restricted to the Adriatic Sea in the Eastern Mediterranean ( Soest et al. 2016). In this study, we found two species of this genus, T. mismalolli and T. calpulli in Costa Rica. Guzmán’s material was very likely T. mismalolli , as the spicules of T. mollis and T. mismalolli are similar.