Amphoriscus pedunculatus Klautau, Cavalcanti & Borojevic, 2017

Chagas, Cléslei & Cavalcanti, Fernanda F., 2021, Partial taxonomic revision of Amphoriscus Haeckel, 1870 (Porifera: Calcarea) with description of A. decennis sp. nov., Zootaxa 5061 (1), pp. 39-68 : 51-53

Amphoriscus pedunculatus Klautau, Cavalcanti & Borojevic, 2017

Amphoriscus pedunculatus Klautau, Cavalcanti & Borojevic, 2017

Citations: Amphoriscus pedunculatus Klautau, Cavalcanti & Borojevic 2017: 105 ; Cóndor-Luján et al. 2019: 1825.

Type material: UFRJPOR 5802 (Holotype). Saco do Poço , São Sebastião, São Paulo State, Brazil (23° 45’ 40.3” S – 45° 14’ 53.5” W); 13 m depth; F. F. Cavalcanti, V. Padula & L. Kremer; 03 December 2008 . UFRJPOR 5803 (Paratype). Saco da Ponta Grossa , São Sebastião, São Paulo State, Brazil (23° 46’ 31.8” S – 45° 13’ 54.8” W); 6 m depth; F. F. Cavalcanti & V. Padula, 03 December 2008 .

Type locality: Saco do Poço , São Sebastião, São Paulo State, Brazil .

Analysed material: UFRJPOR 5802 (holotype; specimen and slides containing sections of the skeleton and dissociated spicules). UFRJPOR 5803 (paratype; specimen and slides containing sections of the skeleton and dissociated spicules). UFRJPOR 5801 (specimen and slides containing sections of the skeleton and dissociated spicules), Serraria Island , São Sebastião, São Paulo, Brazil (23° 48’ 47.9”S – 45° 13’ 44.0”W); 9 m depth; F. F. Cavalcanti & V. Padula, 04 December 2008 . MNRJ 5818 (specimen and slides containing sections of the skeleton and dissociated spicules). Alcatrazes Archipelago , São Sebastião, São Paulo, Brazil (24° 06’ 00.0” S – 45° 40’ 59.9” W); 12 m depth; M. Custódio & C. Santos, 03 May 2002 . UFRJPOR 5776 (specimen and slides containing sections of the skeleton and dissociated spicules), Saco da Saia , Arraial do Cabo, Rio de Janeiro, Brazil (23° 00’ 23.0” S – 42° 00’ 36.0” W); 1 m depth; G. Muricy, 17 March 1988 .

Morphology: The specimens are similar in size and shape, with tubular shape and apical osculum surrounded by a delicate fringe of trichoxeas ( Fig. 7A ). The peduncle is white in live specimens and brownish/orange in ethanolpreserved specimens, but the peduncle is brownish/orange. The surface is slightly hispid due to the trichoxeas of the cortical region. The atrial cavity is hispid and fills the entire body of the specimens. The aquiferous system is syconoid.

Anatomy: The cortical region has several broken spicules. It is mostly formed by giant tetractines with long apical actines. Triactines are also present, but they are less abundant ( Fig. 7B and C ). Trichoxeas are abundant throughout the entire cortex ( Fig. 7D ) and may reach the choanosome ( Fig. 7E ). The subatrial region is comprised exclusively of triactines. They vary in size, but the unpaired actine is always long ( Fig. 7C ). The atrial skeleton is comprised of tetractines ( Fig. 7F ).

Spicules ( Table 4; Fig. 8 ):

Trichoxeas: Very thin, fusiform with sharp tips. Straight or slightly curved. Mostly broken ( Fig. 7D ).

Cortical triactines ( Fig. 8A ): Conical with blunt tips. The paired actines are slightly curved. The unpaired actine is straight.

Cortical tetractines ( Fig. 8B ): Conical with blunt tips. The paired actines are slightly curved, as well as the unpaired one. The apical actine is straight and long.

Subatrial triactines ( Fig. 8C ): Conical to slightly conical and blunt. Paired actines are short and straight. The unpaired actine is straight.

Atrial tetractines: Slightly conical and sharp. Paired actines are slightly curved and larger or the same size as the apical actine. The unpaired actine is straight and longer than the other actines. The apical actine is straight ( Fig. 8D ).

Remarks: Amphoriscus pedunculatus was recently described ( Klautau et al. 2017), with an original description in which important taxonomic characters were fully described and illustrated. The redescription provided in the present study differs only with respect to the tips of the spicules: cortical and subatrial spicules are described here as having blunt tips while they were reported as being sharp in the original description. In our opinion, the differentiation between blunt and sharp tips may not always be obvious, but the availability of images (as in Figure 8 ) helps resolve any doubts. Slight differences were also found in the measurements of the cortical tetractines of the holotype: according to Klautau et al. (2017), the range observed in the length of the unpaired actine is larger (120.0– 238.5 ±58.2–350.0 µm) than that obtained here (177.8– 182.9 ±7.2–188.0 µm). These differences may be related to the existence of several microscopical slides containing dissociated spicules, and the largest spicules may not be evenly distributed.

Among the species with peduncle, Amphoriscus pedunculatus is the only one with a subatrial skeleton formed exclusively by triactines. The remaining species, A. chrysalis , A. cyathiscus , and A. testiparus , have both triactines and tetractines or only tetractines.

Distribution: The species seems to be restricted to the southeastern Brazilian coast in São Sebastião (São Paulo state), and Arraial do Cabo (Rio de Janeiro state) ( Klautau et al. 2017).

Distribution: São Sebastião (São Paulo state) and Arraial do Cabo (Rio de Janeiro state). Corresponding MEOW: Southeastern Brazil ( Spalding et al. 2007).

Figures

FIGURE 7. Amphoriscus pedunculatus (B–F: holotype UFRJPOR 5802). A—Specimens in ethanol (paratype UFRJPOR 5803). B—Section of the cortex. C—Skeletal organization. Arrow indicates a triactine. D—Subcortical region with trichoxeas (arrow). E—Trichoxeas (arrow) close to subcortical lacunae (*). F—Atrial region with tetractines.

FIGURE 8. Amphoriscus pedunculatus (holotype UFRJPOR 5802). A—Cortical triactine. B—Cortical tetractine. C—Subatrial triactine. D—Atrial tetractine.