Leucandra caribea Cóndor-Lújan, Louzada, Hajdu & Klautau, 2018

Pereira, Sara Emilly, Azevedo, Fernanda, Hajdu, Eduardo, Cavalcanti, Fernanda F. & Klautau, Michelle, 2025, Calcareous sponges (Porifera, Calcarea) from São Sebastião, São Paulo: new species and new records in two marine protected areas of Southeastern Brazil Ecoregion, Zootaxa 5688 (1), pp. 1-107 : 51-53

Leucandra caribea Cóndor-Lújan, Louzada, Hajdu & Klautau, 2018

( Figs. 26 , 27 ; Table 12)

Synonyms: Leucandra caribea — Cóndor-Lújan et al. 2018: 35.

Type locality: Tug Boat , Caracasbaai, Willemstadt, Curaçao (Caribbean Sea) .

Material examined: MNRJ5856 , Búzios Island , Ilhabela, São Paulo State, Brazil, depth 8 m, coll. E. Hajdu & M. Ventura , 30/IV/2002. UFRJPOR6932, Sumítica Island , Ilhabela, São Paulo State, Brazil, depth 9 m, coll. F. F. Cavalcanti & V. Padula, 02/XII/2008. UFRJPOR7023, 9088, Coroa , Búzios Island, Ilhabela, São Paulo State, Brazil, depth 15 m, coll. F. F. Cavalcanti , V. Padula & L. Kremer, 05/XII/2008. UFRJPOR9083, Velasquez shipwreck, São Sebastião Island, Ilhabela, São Paulo State, Brazil, depth 13 m, coll. F. F. Cavalcanti , 30/XI/2008. UFRJPOR9087, Saco do Poço , São Sebastião Island, Ilhabela, São Paulo State, Brazil, depth 13 m, coll. F. F. Cavalcanti , V. Padula & L. Kremer, 03/XII/2008. UFRJPOR9301, Alcatrazes Archipelago , São Sebastião, São Paulo State, Brazil, depth 4–8 m, coll. S. López , 18/III/2023.

Comparative material examined: Holotype of Leucandra caribea —UFRJPOR6754, Tug Boat , Caracasbaai, Willemstadt, Curaçao (12.06894, -68.86233), depth 13.9 m, coll. B. Cóndor-Luján, 23/VIII/2011.

Colour: Beige or white in life and white in ethanol ( Fig. 26A, B ).

Morphology and anatomy: This sponge varies in morphology from vase-shaped to globular ( Fig. 26A, B ), with a single, apical osculum surrounded by a membrane with a few short trichoxeas that do not form a conspicuous crown ( Fig. 26C ). The external surface is smooth and soft, and the consistency is compressible. The atrial cavity is also smooth, as tetractines are rare. Aquiferous system leuconoid.

The skeleton of the oscular membrane is composed of T-shaped triactines and rare tetractines arranged in parallel, supporting a very short crown of trichoxeas, which is only visible under a microscope ( Fig. 26C ). The cortical skeleton is composed of an outer layer of small triactines and an inner layer of large triactines, the latter similar to the choanosomal ones ( Fig. 26D ). Additionally, there are short fragments of trichoxeas scattered through the cortex, especially near the osculum. The choanosomal skeleton is disorganised and formed by large triactines ( Fig. 26E ). The exhalant canals are abundant in the choanosome and lined by numerous tetractines and rare triactines, with the apical actines facing their lumen ( Fig. 26F ). The atrial skeleton is composed of triactines and few tetractines ( Fig. 26G ).

Spicules ( Table 12):

Trichoxeas: Short, very thin and cylindrical. Usually broken ( Fig. 27C ). Size:>112.0/1.3 µm.

Small cortical triactines: Slightly sagittal. Actines are slightly conical, with sharp tips. The unpaired actine is straight and often a little shorter than the paired ones, which are curved ( Fig. 27A ). Size: paired—255.0 (±44.3)/13.4 (±2.6) µm; unpaired—231.3 (±54.9)/14.4 (±2.0) µm.

Large cortical triactines: Identical in shape and size to the choanosomal triactines ( Fig. 26D , arrowhead 2). Size: 554.0 (±63.5)/47.0 (±5.7) µm.

Choanosomal triactines: Regular to subregular. Actines are straight, conical and sharp. Greatly variable in size, but most of them are large ( Fig. 27B ). Size: 716.3 (±209.2)/51.7 (±16.6) µm.

Triactines and tetractines of the canals: Slightly sagittal. Basal actines are cylindrical to slightly conical, with sharp tips. The unpaired actine is straight and similar in length to the paired ones, which are curved ( Fig. 27C ). The apical actine of the tetractines is short, curved, conical and sharp. Triactines size: paired—196.7 (±12.9)/13.8 (±1.4) µm; unpaired—196.3 (±43.9)/15.6 (±1.3) µm. Tetractines size: paired—196.5 (±34.6)/11.9 (±2.4) µm; unpaired— 198.3 (±48.3)/13.5 (±2.2) µm; apical—65.6 (±12.1)/9.3 (±1.5) µm.

Atrial triactines and tetractines: Strongly sagittal. Basal actines are slightly conical to conical, with sharp tips. The paired actines are straight or slightly curved and longer than the unpaired one ( Fig. 27D, E ). The apical actine of the tetractines is short, curved, smooth, conical and sharp. Triactines size: paired—253.8 (±48.3)/15.5 (±2.6) µm; unpaired—184.0 (±39.1)/15.6 (±2.8) µm. Tetractines size: paired—230.5 (±49.7)/14.4 (±2.7) µm; unpaired—176.5 (±44.4)/16.6 (±2.5) µm; apical—68.4 (±13.7)/10.5 (±1.5) µm.

Ecology: Most specimens were found in caves and other areas protected from sunlight, except for UFRJPOR7034, which was found exposed to sunlight, in association with algae.

Geographic distribution: Southern Caribbean ecoregion— Curaçao ( Cóndor-Luján et al. 2018). Southeastern Brazil ecoregion—São Sebastião, Búzios and Sumítica Islands (Ilhabela) and Alcatrazes Archipelago (São Sebastião), São Paulo State (present study), Brazil.

Remarks: The external morphology and the skeletal composition of the specimens match the original description of L. caribea , first described from Curaçao, and so far, considered endemic to the Caribbean Sea. Nevertheless, based on the original description, we identified minor potential differences regarding the atrial spicules: according to the measurements provided by Cóndor-Luján et al. (2018), the atrial triactines and tetractines have the unpaired actine similar to or longer (on average) than the paired ones [atrial tetractines—paired actines: 206.9 (±28.7) µm, unpaired actine: 237.6 (±35.1) µm], whereas in the specimen MNRJ5856 the inverse proportion was observed, i.e., the unpaired actine is shorter than the paired ones [atrial tetractines—paired actines: 230.5 (±49.7) µm, unpaired actine: 176.5 (±44.4) µm]. Additionally, the atrial spicules of the holotype seem less sagittal in the original description than in our specimens ( Cóndor-Luján et al. 2018, Fig. 20E, F ). To evaluate these potential differences, we anaysed tangential sections of the atrial skeleton of the holotype of L. caribea . Many of the atrial spicules in L. caribea have the unpaired actine shorter than the paired ones. Besides, most of these spicules were strongly sagittal, similar to those in the Brazilian specimens, corroborating our identification. Thus, the distribution of L. caribea is here expanded to the southeastern Brazilian coast, and comprises a large distribution gap where the species has not yet been reported from, including the Brazilian north and northeast coasts.

Figures

FIGURE 20. Grantia kempfi (UFRJPOR7009). A. Preserved specimen. B. Cross section of the body wall. C. Cross section showing the cortical skeleton (ostiolar triactines in the inset). D. Cross section showing the tubar skeleton. E. Subatrial triactines (arrows) and apical actines of the atrial tetractines. F. Tangential section of the atrial skeleton. cx = cortex, at = atrium.

FIGURE 26. Leucandra caribea. A, B. Preserved specimens MNRJ5856 and UFRJPOR7023 (arrow points to the oscular membrane). (C–G) MNRJ5856. C. Oscular skeleton (arrowhead in the inset points to short trichoxeas). D. Tangential section of the cortical skeleton, showing the small (arrowhead 1) and large (arrowhead 2) cortical triactines. E. Cross section of the body wall. F. Triactines (arrowhead 1) and tetractines (arrowhead 2) of the canals. G. Tangential section of the atrium. cx = cortex, at = atrium, c = exhalant canals.

FIGURE 27. Leucandra caribea (MNRJ5856).A. Cortical triactines. B. Choanosomal triactines. C. Triactine and tetractines of the canals. D. Atrial triactines. E. Atrial tetractines.