Leucilla uter Poléjaeff, 1883

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 : 26-30

Leucilla uter Poléjaeff, 1883

( Figs. 12 , 13 ; Table 7)

Synonyms: Leucilla uter — Poléjaeff 1883: 53 (except for the specimens BMNH.1884.4.22.30 and BMNH.1884.4.22.31, from Philippines); Dendy 1892: 114; Dendy 1893: 185; Dendy & Row 1913: 784; Borojević & Boury-Esnault 1987: 35; Muricy et al. 1991: 1187; Muricy & Silva 1999: 160; Muricy et al. 2011: 25; Cóndor-Luján et al. 2019: 14. Polejna uter — Lendenfeld 1885: 1115. Leucilla australiensis (in part.)— Borojević 1967: 221 [non Leucilla australiensis ( Carter, 1886) ; non Leucilla australiensis sensu Borojević & Peixinho 1976 ].

Type locality: Bermuda, British Overseas Territory , North Atlantic Ocean .

Material examined: MNRJ30126 , MNRJ30127 , MNRJ30129 , Alcatrazes Archipelago , São Sebastião, São Paulo State, Brazil, depth 12 m, coll. M. Custódio & C. Santos, 03/ V /2002. MNRJ5855 , Celada , São Sebastião Island, Ilhabela, São Paulo State, Brazil, depth 8 m, coll. E. Hajdu & M. Carvalho, 01/ V /2002.

Comparative material examined: Lectotype of Leucilla uter — BMNH.1884.4.22.21 (slides), Bermuda, Challenger Exp., station 36, 23/IV/1873, depth 59 m.

Colour: White in life and white or beige in ethanol ( Fig. 12A, B ).

Morphology and anatomy: The external morphology ranges from vasiform to tubular ( Fig. 12A, B ), with a single apical osculum, ornamented with a crown of trichoxeas ( Fig. 12C ). The consistency is friable, and the surface is rough. The external surface is slightly hispid, particularly near the osculum, where large diactines are concentrated, protruding through the cortex (arrows in Fig. 12A, B ). The atrial cavity is wide and hispid.Aquiferous system sylleibid, with nearly spherical choanocyte chambers radially arranged around exhalant canals ( Fig. 12D ).

The skeleton of the oscular margin that supports the crown of trichoxeas is composed of diactines, tetractines and rare triactines ( Fig. 12C ). The cortical skeleton is composed of rare diactines perpendicularly positioned on the surface and concentrated in the suboscular region, in addition to the basal actines of cortical tetractines, rare triactines and a few fragments of trichoxeas ( Fig. 12E ). The diactines can cross the choanosome. The choanosomal skeleton is composed of the apical actine of the cortical tetractines and the unpaired actine of the subatrial triactines and tetractines ( Fig. 12D, F ). The subatrial spicules occur adjacent to the atrium, or slightly displaced, forming one or two additional layers in the choanosome, but the skeleton remains inarticulate. The subatrial tetractines are a little more abundant than the triactines. The atrial skeleton is formed almost exclusively by tetractines, as triactines are very rare ( Fig. 12G ).

Spicules ( Table 7):

Trichoxeas: Very thin, cylindrical and always broken (some fragments found on the cortex). Size:>850.0/5.0 µm.

Diactines: Fusiform, straight or curved, with both tips sharp ( Fig. 13A ). Often broken. Size:>800.0/25.0 µm.

Cortical triactines: Sagittal, but extremely variable in shape and size. Some are robust, with conical actines similar to the basal system of the cortical tetractines. Others are much thinner, with cylindrical actines, resembling the subatrial and atrial spicules, and with the unpaired actine straight and longer than the basal ones, which are inwardly or outwardly curved ( Fig. 13B ). Size: paired—160.2 (±45.0)/11.3 (±6.1) µm; unpaired—222.0 (±92.2)/11.8 (±5.0) µm.

Cortical tetractines: Large, sagittal. Basal actines are straight, conical and sharp. The unpaired actine is frequently a little shorter than the paired ones ( Fig. 13C ). The apical actine is long, conical to slightly conical, straight and sharp. Size: paired—265.8 (±32.2)/28.5 (±5.0) µm; unpaired—259.0 (±39.6)/28.0 (±3.5) µm; apical— 337.3 (±69.1)/26.1 (±4.3) µm.

Subatrial triactines and tetractines: Sagittal, but variable in shape and width. Basal actines are slightly conical to cylindrical and sharp. The unpaired actine is straight or slightly undulated and longer than the paired ones, which are inwardly curved and sometimes unequal in length. The apical actine of the tetractines is conical, straight or slightly curved and variable in length ( Fig. 13D, E ). Triactines size: paired—210.3 (±54.6)/15.9 (±4.4) µm; unpaired—350.5 (±59.2)/17.6 (±4.3) µm. Tetractines size: paired—214.6 (±53.8)/19.6 (±5.0) µm; unpaired—339.2 (±63.3)/20.1 (±4.6) µm; apical—113.3 (±68.8)/15.1 (±4.2) µm.

Atrial triactines and tetractines: Slightly sagittal (strongly sagittal only near the osculum). Basal actines are cylindrical to slightly conical, with sharp tips. The unpaired actine is straight and usually longer than the paired ones, which are curved and often unequal in length. The apical actine of the tetractines is short, conical, laterally compressed, curved, and sharply pointed ( Fig. 13F ). Tetractines size: paired—171.8 (±35.6)/9.9 (±1.0) µm; unpaired—231.0 (±81.7)/10.2 (±1.2) µm; apical—51.0 (±11.4)/7.1 (±1.2) µm.

Ecology: A polychaete was found inside the specimen MNRJ30127. Another specimen (MNRJ5855) was growing on a bryozoan colony.

Geographic distribution: Bermuda ecoregion— Bermuda Islands, North Atlantic Ocean ( Poléjaeff 1883), British Overseas Territory. Southeastern Brazil ecoregion—Arraial do Cabo, Rio de Janeiro State ( Muricy et al. 1991; Muricy & Silva 1999); São Sebastião Island (Ilhabela) and Alcatrazes Archipelago (São Sebastião), São Paulo State (present study), Brazil. Agulhas Bank ecoregion— South Africa ( Borojević 1967; uncertain). Torres Strait Northern Great Barrier Reef ecoregion— Australia ( Lendenfeld 1885; uncertain).

Remarks: Leucilla uter was originally described by Poléjaeff (1883) from Bermuda and from the Philippines. However, according to a recent unpublished revision of the genus Leucilla (Chagas 2021) , the specimens from the Philippines ( paralectotypes) belong to Paraleucilla . Our specimens from São Sebastião closely match the original description of L. uter , except for the presence of rare spicule types present in our samples but absent in the original description of L. uter (diactines, cortical triactines, and atrial triactines). To verify if these spicules are present and just not mentioned in the original description, we analysed microscope slides of the lectotype of L. uter , from Bermuda (kindly loaned by T. White and C. Valentine, NHM).

Indeed, rare triactines are present in the cortex and atrium of the lectotype. Concerning the diactines, Poléjaeff (1883) reported only the presence of trichoxeas (<400/2.5 µm) in L. uter , not diactines. Nonetheless, in our specimens the diactines are rare and confined to the oscular and suboscular regions. It is possible that the same happened with the type of L. uter , however, it was not possible to verify this because the lectotype is fragmented and no microscope slides of the oscular or suboscular regions are available (Cléslei Chagas, personal communication).

Regarding the aquiferous system of L. uter , it may be considered irregularly sylleibid or intermediate between sylleibid and leuconoid ( Poléjaeff 1883 —see Plate 6, fig. 2a; Lendenfeld 1885; Dendy 1893 —see Plate 13, fig. 21). This ambiguous designation arises from the presence of both spherical choanocyte chambers and elongated chambers arranged around canals. In our specimens, the aquiferous system exhibits a more typical sylleibid structure ( Fig. 12D ).

Borojević & Peixinho (1976) and Borojević & Boury-Esnault (1987) synonymised L. sacculata ( Carter, 1890) and L. australiensis ( Carter, 1886) to L. uter . These synonymies were not accepted by Muricy et al. (2011), however, they regarded specimens from South Africa and the Brazilian coast, previously identified as L. australiensis by Borojević (1967) and Borojević & Peixinho (1976), as L. uter . According to Chagas (2021), the South African specimens likely correspond to Paraleucilla , while those from northeastern and southeastern Brazil match the characteristics of Paraleucilla perlucida . Therefore, L. uter is currently known from the Bermuda and Southeastern Brazil ecoregions ( Poléjaeff 1883; Muricy et al. 1991; Chagas 2021; this study).

Figures

FIGURE 12. Leucilla uter. A, B. Preserved specimens MNRJ30127 and MRNJ 30126 (arrows point to projecting diactines). C. Skeleton of the oscular crown (arrowheads point to diactines), with details of the oscular spicules in the inset. D. Cross section. E. Tangential section of the cortex, showing the cortical triactines (arrowheads and inset). F. Cross section with arrowheads pointing to a subatrial triactine (white arrowhead) and tetractine (black arrowhead). G. Tangential section of the atrium. All skeleton photos were taken from the specimen MNRJ30127. cx = cortex, ec = exhalant canals, at = atrium.

FIGURE 13. Leucilla uter (MNRJ30127). A. Diactines. B. Cortical triactines. C. Cortical tetractines. D. Subatrial triactines. E. Subatrial tetractines. F. Atrial tetractine.