Aaptos potiguarensis, Carvalho, Mariana De S., Da Silva, Suzane M. & Pinheiro, Ulisses, 2013

Carvalho, Mariana De S., Da Silva, Suzane M. & Pinheiro, Ulisses, 2013, Two new species of Aaptos (Demospongiae, Hadromerida) from Brazil (western Atlantic), Zootaxa 3750 (4), pp. 357-366 : 362-363

Aaptos potiguarensis sp. nov.

( Figure 3 C–D, 4; Table 1 )

Type material. Holotype: UFPEPOR 45—Campaign BPOT 0 2, station 33 (Potiguar Basin, Rio Grande do Norte State, 05°00´03.9”S – 36°25´12.1”W), 7–10.2 m depth, coll. R/V ‘Astro Garoupa’, 28/V/2003.

Schyzoholotype: MNRJ 16685.

Paratype: UFPEPOR 46—Campaign BPOT 0 2, station 33 (Potiguar Basin, Rio Grande do Norte State, 05°00´03.9”S – 36°25´12.1”W), 7–10.2 m depth, coll. R/V ‘Astro Garoupa’, 28/V/2003.

Schyzoparatype: MNRJ 16686.

Diagnosis. Aaptos with an ectosomal skeleton without subectosomal cavities, where small styles form a palisade at the surface. Spicules are one category of strongyloxeas with rounded tips (301–1562 µm in length and 8–43 µm thick) and one category of styles (220–590 µm in length and 2.5–11 µm thick).

Description. Specimens are massive, up to 18.8 cm in length and 10.9 cm width (holotype; Fig. 4 A). The base has incrustations of calcareous substrate. Oscules rounded, up to 3 mm in diameter, dispersed on the surface. Surface is irregular, uneven. Consistency is firm, almost incompressible. Color is unknown in the holotype, and light brown alive and beige in spirit, in the paratype.

Skeleton. Ectosomal skeleton with strongyloxeas and styles crossing the surface. Small styles form a palisade at the surface, in which the ends of the strongyloxeas are also present. Choanosomal skeleton is very dense, composed mainly of tracts of strongyloxeas with a radial arrangement, protruding beyond the surface of the sponge ( Fig. 4 B). Little collagen is seen.

Spicules. Megascleres in two categories ( Tab. 1 , Fig. 4 C–D). Choanosomal strongyloxeas ( Fig. 4 C)—smooth, highly fusiform, usually straight or slightly curved, with rounded tips: 301–1562 µm in length and 8–43 µm thick. Ectosomal styles ( Fig. 4 D)—smooth, straight, occasionally curved: 220–590 µm in length and 2.5–11 µm thick. The distinction between strongyloxeas and styles is very subtle and, as in Aaptos hajdui sp. nov., we consider strongyloxeas as fusiform or slightly fusiform and styles are isodiametric.

Etymology. The specific epithet potiguarensis is refers to its type locality, from the Potiguar Basin.

Distribution. Provisionally endemic from Potiguar Basin (Rio Grande do Norte State, north-eastern Brazil).

Ecology. Bryozoans and polychaetes were found associated to both specimens. This species occurs in shallow waters, from 7 to 10 m depth on rocky substrate.

Remarks. Nine species of the genus Aaptos have tylostyles and/or subtylostyles as ectosomal spicules, thus differing from A. potiguarensis sp. nov.: A. aaptos (holotype and lectotype descriptions sensu Van Soest 2002 and Kelly-Borges & Bergquist 1994); A. alphiensis ; A. globosum ; A. kanuux ; A. laxosuberites ; A papillata ; A. robustus ; A. rosacea ; and A. tentum . Other species such as A. confertus and A. horrida possess oxeas as dermal or additional spicules, and A. pernucleata have true oxeas as main megascleres (as observed in figures of Carter, 1870). Aaptos aaptos possesses two categories of strongyloxeas, in a similar size range of the strongyloxeas of A. potiguarensis sp. nov., although some other differences can be observed. Besides having styles to substylostyles as dermal spicules, A. aaptos (holotype and lectotype, see Table 2 ) has its category smaller than in A. potiguarensis sp. nov.

Aaptos hajdui sp. nov. is different from A. potiguarensis sp. nov. due to the telescopic/mucronate ends of the strongyloxeas in the former, in addition to the differences in the skeleton, as the presence of subectosomal cavities and the megascleres of the choanosomal skeleton forming bouquets near the surface. Besides, A. hajdui sp. nov. is globular and almost black after fixation, while A. potiguarensis sp. nov. is massive, turning beige after fixation in ethanol.

Figures

FIGURE 3. Distribution frequency of the size-classes of the strongyloxeas of Aaptos hajdui sp. nov. (A. UFPE POR 62; B. UFPE POR 181) and A. potiguarensis sp. nov. (C. UFPE POR 45; D. UFPE POR 46). (n = 100). x-axis size in microns; y-axis frequency in number of spicules per size class.

FIGURE 4. Aaptos potiguarensis sp. nov. A. Holotype (UFPEPOR 45). B. Choanosomal skeleton. C. Strongyloxeas. D. Styles. Scale bars: A = 5 cm. B = 500 µm. C, D = 100 µm.