Aplysina alcicornis, Pinheiro, Ulisses Dos S., Hajdu, Eduardo & Custódio, Márcio R., 2007

Pinheiro, Ulisses Dos S., Hajdu, Eduardo & Custódio, Márcio R., 2007, Aplysina Nardo (Porifera, Verongida, Aplysinidae) from the Brazilian coast with description of eight new species, Zootaxa 1609, pp. 1-51 : 29-30

Aplysina alcicornis sp.n. ( Fig. 9 B, 11D, 14, Tab. VII)

Holotype: MNRJ 5473, Coral Head at Parque Nacional Marinho dos Abrolhos (BA), 12 m depth, G. Muricy and E. Esteves coll., 02/III/2002.

Paratype: MNRJ 5472, 5474, southeast Patch Reef (Parque Nacional Marinho dos Abrolhos, BA), 12 m depth, G. Muricy and E. Esteves coll., 02/III/2002.

Diagnosis: Lamellar habit with flattened digitiform branches, conspicuous small apical digitiform projections and oscula with iris-type diaphragms situated in depressions on the surface of the sponge. Specimens turn to dark-brown in ethanol.

Description of the species:

The specimens are lamellar, with 11 cm in width 10 cm in height and 1 cm in thickness. The general appearance somewhat resembles the fire coral Millepora alcicornis Linneus, 1758 , larger digitiform projections being observed at the base and the apex of the specimens. In the upper part of these larger projections, several much smaller apical digitiform projections up to 1 cm long, can be observed ( Fig. 9 B). These fistules are frequently branching dichotomously or trichotomously, and remained on specimens after preservation ( Figs. 14A–B ). Oscula 0.3 cm in diameter, bearing iris-type diaphragms are situated in depressions which occur close to the apical portion of the lamellas. Other oscula, with 0.1 cm, open on the sides of the sponge. The surface is finely conulose. The colour is brown or yellow in vivo, turning to dark-brown after preservation in alcohol. Consistency is compressible.

Skeleton: Choanosome with a delicate and irregular network of spongin fibers with amber coloured bark and thickness of 40–142 Μm (average 92 Μm) and a thick black or amber pith with thickness of 15–82 Μm (average 24 Μm; Figs. 14C–D ; Table VII). In the small apical digitiform projections, the fibers present a dendritic arrangement. In these structures the fibers are composed mostly by the pith, with only a thin layer of bark.

TABLE VII: Spongin fibres’ measurement data for Aplysina alcicornis sp.n. (in micrometers; S.D. = Standard Deviation and N=30).

Specimens Locality* Fibers Piths Distribution: Provisionally known only from Parque Nacional Marinho dos Abrolhos, (Bahia State, Brazil; Fig. 11 D).

Ecology: All the specimens were collected at 12 m depth, attached on the sides of coral heads. Etymology: The name of this species stresses its resemblance to the fire coral Millepora alcicornis . Remarks: The species which most closely resembles A. alcicornis sp.n. is A. cristagallus sp.n. which is described below. Aplysina insularis sensu Zea (1987; Pl. 6, fig. 5) bear some resemblance to A. alcicornis sp.n. (non A. insularis of authors). Nevertheless, Zea´s specimen is not considered conspecific on the basis of its markedly anastomosed cluster of otherwise cylindrical branches topped by oscula, which contrasts to the overall flattened habit of the new species.

Figures

FIGURE 9: A. Aplysina insularis (Duchassaing & Michelotti, 1864: 64). B. Aplysina alcicornis sp. n. in situ, Holotype – MNRJ 5473 (Parque Nacional Marinho dos Abrolhos, BA, Brazil). C. Aplysina cristagallus sp. n. in situ, Holotype— MNRJ 3528 (Prado, BA, Brazil). Scale bar = 1 cm.

FIGURE 11: Map showing the distribution of Aplysina along the Brazilian coastline. A. Aplysina insularis (Duchassaing & Michelotti, 1864) B. Aplysina lacunosa (Pallas, 1766). C. Aplysina pergamentacea Hechtel, 1983. D. Aplysina alcicornis sp. n.. Scale bar = 500 km.

FIGURE 14: A – D. Aplysina alcicornis sp. n. Holotype (MNRJ 5473). A – B. habit after preservation. C. Skeletal architecture. D. Spongin fibres. Scale bars = A – B. 1 cm, C. 500 µm, D. 50 µm.