Pione cf. carpenteri (Hancock, 1867)

Material examined. MZUCR.377: Isla del Caño, 5 m, 12. II.2011, coll. and det. Cristian Pacheco Solano . MZUCR.376: Bahía Culebra, 3 m, 21.III.2011, coll. and det. Cristian Pacheco Solano . MZUCR.379: Playa Mantas, 2 m, 16.IX.2011, coll. and det. Cristian Pacheco Solano . ICMYL. Pca. 83.R, ICMYL. Pca. 86.R, ICMYL. Pca. 92.R, ICMYL. Pca. 98.R, ICMYL. Pca. 99.R, ICMYL. Pca. 103.R: Playa Matapalo, 3 m, 20.XII.2012, coll. and det. Cristian Pacheco Solano . ICMYL. Pca. 126.FS: Bahía Culebra, 3 m, 20.XII.2012, coll. and det. Cristian Pacheco Solano . ICMYL. Pca. 137.IT: Isla Taboga, Gulf of Panama, 1 m, 13.I.2012, coll. and det. Cristian Pacheco Solano .

External morphology. Endolithic sponge in alpha morphology. Papillae small, sometimes difficult to observe, average diameter of 390 µm. Live color yellow.

Excavation. Erosion multicamerate (Fig. 26A). Oval or irregular chambers with diameters of 0.8 to 1.6 mm. Erosion scars 20 to 102 µm in diameter (Fig. 26B).

Spicules. Megascleres straight tylostyles, scarce. Microscleres microspined oxeas curving mid-shaft and straight, microspined microrhabds (Fig. 27). Tylostyle dimensions: 181–217 µm (x̅ =202.6, σ=17.7) x 3-5 µm (x̅ =4.2, σ=0.6). Oxea dimensions: 63–115 µm (x̅ =84.4, σ=21.4) x 3–6 µm (x̅ =4, σ=1.7). Microrhabd dimensions: 9–12 µm (x̅ =11, σ=1.9) x 1–3 µm (x̅ =1.7, σ=0.4).

Ecology. Found in dead Pocillopora sp. and shells of dead mollusks, between 1 and 5 m depth.

Distribution and previous records. The species was originally described as Cliona carpenteri from Mazatlan (Hancock 1867), Mexico. Recently, more specimens have been collected along the Pacific coast of Mexico (Carballo et al. 2004, 2008a) and Panama (Vega 2012). It has also widely been reported from other locations such as Brazil (Muricy et al. 2011). However, records for the Gulf of Mexico and Myanmar were considered as uncertain (Soest et al. 2016). Scott et al. (1988) mentioned the presence of Pione lampa (Laubenfels, 1950) at Caño Island (Costa Rica), which is most likely a misidentification for this Atlantic sponge (Soest et al. 2016). We have no means to assess which Pione species they referred to. If they decided on P. lampa because it had a beta morphology, then we rule out that they meant P. carpenteri . In this study the latter species ocurred in Nicaragua, Costa Rica and Panama, with the first two countries being new records for it (Fig. 28).

Remarks. We described P. carpenteri with the “conferre” epithet (“cf.”), because it belongs to a taxonomically difficult and not well-documented genus and because it does not differ much from other Pione species in Mexico. It largely compares well to P. carpenteri as described by Carballo et al. (2004), but the microspination of the microrhabds and oxeas in the Mexican samples is less pronounced than in the Central American samples. At this stage, most records of Pione species cannot easily be accepted as correct, and further studies are warranted.