Dragmaxia anomala, Carvalho & Hajdu, 2004

Carvalho, Mariana De S. & Hajdu, Eduardo, 2004, Dragmaxia anomala sp. n. (Demospongiae: Halichondrida) from the southwestern Atlantic (Brazil), Zootaxa 400 (1), pp. 1-6 : 3-6

Dragmaxia anomala sp.n.

( Fig. 2A–F ; Tab. I)

Holotype. Ilhabela: MNRJ 122 , Saco da Serraria (23º48.344’S – 45º14.401’W), Ilhabela , São Sebastião , São Paulo State, 13m depth, col. E. Hajdu, 11/i/1996.

Paratypes. Ilhabela: MNRJ 124 , Saco da Serraria , Ilhabela , São Sebastião, São Paulo State, 13m depth, col. E. Hajdu, 11/i/1996 ; MNRJ 500 , Codo Islet (23º55.206’S – 45º17.936’W), Saco das Anchovas, Ilhabela, São Sebastião, São Paulo State, 15–17m, col. E. Hajdu, 22/vi/1997 ; MNRJ 788 , Ilha da Serraria (23º48.758’S – 45º13.812’W), Ilhabela, São Sebastião, São Paulo State, 20m, col. E. Hajdu, 11/i/1996 .

Diagnosis. Dragmaxia anomala sp.n. is set apart from the other species of the genus by its encrusting shape with digitated projections and its yellowish­orange colour alive. Megascleres are a single category of styles and subtylostyles. Raphides ornamented are absent.

Description. Encrusting with digitated projections, up to 2cm high, compressible with an hispid surface ( Fig. 2A ). The projections can be forked ( Fig. 2B ). Colour alive is yellow to yellowish­orange, the surface can be white, and specimens become whitish in alcohol.

Skeleton. No specialized ectosomal skeleton. Choanosomal skeleton plumose ( Fig. 2C ) with spicular axes ascending to the surface, usually dendritically. Figure 2C shows a vestige of axial condensation.

Spicules ( Fig. 2D–F ; Tab. I). Megascleres are styles slightly curved with 180–730µm in length and 7–20µm thick. (Subtylo)styles slightly curved, nearly straight, with 140– 470µm in length and 10–20µm thick. Microscleres are rare smooth raphides with 72–384 µm in length.

Distribution and ecology. Known only from Ilhabela, São Sebastião, São Paulo State. The species is rare. The specimens were collected at 13–20m depth. MNRJ 500 was found on top or a large rock, semi­covered by sediment.

Etymology. The species is named after its seemingly uncommon characteristic of possessing raphides which are unornamented, a character so far judged decisive diagnostically.

Remarks. An alternative identification for the new species would be in Monanchora Carter, 1883 ( Crambeidae , Poecilosclerida , Demospongiae) due to the form of its megascleres, similar to those observed in this genus, which can also present a plumose skeleton (in encrusting forms). However, Monanchora has conspicuous spongin and functional specialization of its megascleres, two characters not observed in Dragmaxia anomala sp.n. Monanchora usually presents chelas or derived microscleres, but these can be rare (Van Soest et al. 1996).

Only two species of Dragmaxia were known until now, D. variabilis (Whitelegge, 1907) , from the east coast of Australia, and D. undata Alvarez et al., 1998 , from Dutch Antilles and Colombia, Caribbean. Both possess ornamented raphides as microscleres, a morphologic trait not matched by the studied material. Dragmaxia anomala sp.n. is nevertheless considered to belong to the genus in view of its styles forming ascending, dendritic tracts (plumose choanosomal skeleton), a decision corroborated by Rob van Soest and Belinda Alvarez (in litt.). This pattern is similar to that seen in the type species, D. variabilis , despite less dense ( Alvarez & Hooper 2002). The specimens´ shape recall the “irregular thin projections, sometimes dichotomously branched” reported by Alvarez et al. (1998). The occurrence of rare smooth raphides in the Brazilian material is considered unimportant here, and could be interpreted as a plesiomorphic trait retained in the new species.

Figures

FIGURE 2. Dragmaxia anomala sp.n. A. Specimen seen alive (Paratype, MNRJ 500). B. Holotype (MNRJ 122) fixed and preserved in alcohol (Scale bar = 1cm). C. Choanosome skeleton (Scale bar = 200µm). D. Styles and (subtylo)styles (Scale bar = 100µm). E. Raphide (Scale bar = 10µm). F. Raphide in detail (Scale bar = 5 m).