Leucandrilla quadriradiata, Cóndor-Luján & Louzada & Hajdu & Klautau, 2018

LEUCANDRILLA QUADRIRADIATA View in CoL SP. NOV.

( FIGS 21–23 View Figure 21 View Figure 22 View Figure 23 ; TABLE 14)

Etymology: Derived from the predominance of tetractines in the skeleton of the species.

Type Locality: Water Factory , Willemstadt, Curaçao .

Material examined: Holotype. UFRJPOR 6705, Water Factory , Willemstadt, Curaçao (12°12′43.12″N, 69°05′8.42″W), 3–5 m depth, coll. B. Cóndor-Luján, 18 August 2011 GoogleMaps . Paratypes. UFRJPOR 6696, Sunset Waters , Soto, Curaçao (12°07′18.94″N, 68°58′11.46″W), <10 m depth, coll. B. Cóndor-Luján and G. Lôbo-Hajdu, 17 August 2011 GoogleMaps . UFRJPOR 6752, Tug Boat , Caracasbaai, Willemstadt, Curaçao (12°04′08.20″N, 68°51′44.40″W), 15.2 m depth, coll. E. Hajdu, 23 August 2011 GoogleMaps .

Diagnosis: Leucandrilla with a cylindrical body. The choanosomal and atrial skeletons are exclusively composed of tetractines.

Colour: White to light blue in life ( Fig. 21A, B View Figure 21 ) and white to beige in ethanol ( Fig. 21C–E View Figure 21 ).

Morphology and anatomy: This species has a cylindrical massive body ( Fig. 21A–E View Figure 21 ). The holotype (UFRJPOR 6705) is fragmented (1.3 × 1.0 × 0.5 cm). The largest specimen (paratype UFRJPOR 6752) measures 3.8 × 2.0 × 0.8 cm ( Fig. 21C View Figure 21 ). The surface is slightly hispid and the consistency is hard. The osculum is apical and its diameter is 1.2 mm. The atrial cavity is not hispid. The aquiferous system is leuconoid with subspherical choanocyte chambers ranging from 75.6 to 162.0 µm in diameter. The diameter of canals varied from 108.0 to 238.0 µm.

Skeleton: In the three analysed specimens, the oscular margin is composed of T-shaped spicules including triactines and rare tetractines ( Fig. 22A View Figure 22 ). The skeleton is not typical of the genus as it has rare pseudosagittal tetractines ( Fig. 22B View Figure 22 ). The cortical skeleton is composed of triactines tangentially positioned on the surface ( Fig. 22B, C View Figure 22 ) and of the basal actines of large sagittal tetractines. Some of them are pseudosagittal ( Fig. 22D View Figure 22 , white arrow). The apical actines of the cortical tetractines cross the choanosome and sometimes reach the atrial skeleton. The choanosomal skeleton is disorganized, formed by the same large tetractines of the cortex. The choanosomal canals are surrounded by small tetractines which have an apical actine projected into them ( Fig. 22E View Figure 22 ). The poorly developed subatrial skeleton is formed by rare tetractines ( Fig. 22D View Figure 22 , black arrow). The atrial skeleton is exclusively composed of tetractines with an apical actine which is projected into the atrial cavity ( Fig. 22F View Figure 22 ).

Spicules: Cortical triactines. Sagittal. Actines are conical with blunt to sharp tips. Some paired actines are slightly curved ( Fig. 23A View Figure 23 ). Highly variable size: 97.2– 421.2/8.1–21.6 µm (paired actine), 75.6–421.2/5.4– 21.6 µm (unpaired actine). Cortical and choanosomal tetractines. Sagittal. Actines are conical with sharp tips. The paired actines are slightly curved ( Fig. 23B View Figure 23 ). Rare pseudosagittal-like tetractines were also observed ( Fig. 23C View Figure 23 ). Size: 248.4–1188.0/27.0–75.6 µm (paired actine), 162.0–564.0/27.0–64.8 µm (unpaired actine) and 345.6–1122.0/21.6–75.6 µm (apical actine). Canal tetractines. Sagittal. Actines are conical with sharp tips. The paired actines are curved following the shape of the canals and they are longer than the other actines ( Fig. 23D View Figure 23 ). Size: 118.8–264.6/8.1–17.6 µm (paired actine), 70.2–213.3/8.1–17.6 µm (unpaired actine) and 40.5–132.3/8.1–13.5 µm (apical actine). Subatrial tetractines. Sagittal. Actines are conical with sharp tips ( Fig. 23E View Figure 23 ). The apical actine is shorter than the basal ones. Size: 205.2–993.6/21.6–75.6 µm (paired actine), 205.2–766.8/21.6–70.2 µm (unpaired actine) and 129.6–432.0/16.2–54.0 µm (apical actine). Atrial tetractines. Sagittal. Actines are conical with blunt to sharp tips ( Fig. 23F View Figure 23 ). Sometimes, the paired actines are slightly curved. The apical actine is conical, shorter than the basal ones, smooth and has sharp tip. Size: 67.5–391.5/8.1–21.6 µm (paired actine), 59.4–270.0/8.1–21.6 µm (unpaired actine) and 21.6– 108.0/6.4–13.5 µm (apical actine).

Ecology: The three specimens were collected in light-protected habitats at depths varying from 5 to 15 m.The holotype (UFRJPOR 6705) and one of the paratypes (UFRJPOR 6696) were collected underneath boulders. A polychaete was found inside one of the paratypes (UFRJPOR 6752).

Geographical distribution: Southern Caribbean (provisionally endemic to Curaçao, present study).

Molecular analysis: The C-LSU sequences of the specimens of L. quadriradiata sp. nov., UFRJPOR 6696 (paratype) and UFRJPOR 6705 (holotype), clustered together in a monophyletic clade with high support (pp = 1, b = 99, Fig. 15 View Figure 15 ). The genetic variability between them was 0%.

Leucandrilla quadriradiata sp. nov. appeared as a new lineage in a large clade recovered with high support values (pp = 1, b = 90). This clade was composed of one Grantiidae , Leucandra nicolae Wörheide & Hooper, 2003 and two Amphoriscidae P. dalmatica and P. magna . Within this clade, P. magna appeared as the sister species of L. quadriradiata sp. nov. (pp = 1, b = 91) with 2.2% of p distance.

Taxonomic remarks: The identification of this new species as Leucandrilla is not very clear. Pseudosagittal spicules are expected to be present only in the family Heteropiidae , and in that case, our new species would be closer to Vosmaeropsis Dendy, 1893 . However, large cortical tetractines are not expected to be found in that genus, instead they are characteristic of the family Amphoriscidae . Within that family, we would expect to allocate the new species to Leucilla , as it has leuconoid aquiferous system and the subatrial skeleton is adjacent to the atrial one. Nonetheless, the new species does not have an inarticulated skeleton, which is a diagnostic characteristic of Leucilla .

In the absence of phylogenetic studies indicating which morphological characters are good for the systematics of Calcaronea, we decided to consider the current morphological systematics and to place the new species in Leucandrilla , taking into account Borojevic et al. (2000): ‘ In any calcaronean sponge with a strong cortex, some subcortical spicules may be in the position and have the shape of pseudosagittal spicules, due to the restriction of their growth by the rigidity of the cortical skeleton. They should not be interpreted as an indication that the sponge belongs to the family Heteropiidae ’.

According to Borojevic et al. (2002), three species belong to the genus Leucandrilla : L. intermedia (Row, 1909) from the Red Sea, L. lanceolata (Row & Hôzawa, 1931) from Southwestern Australia and L. wasinensis from East Africa. Herein, we propose to transfer some types = UFRJPOR 6696 and UFRJPOR 6752)

species of the genus Leucandra to Leucandrilla as their original descriptions match the current accepted diagnosis of Leucandrilla . Those species are: L. connectens Brønsted, 1927 from New Zealand, L. fernandensis (Breitfuss, 1898) from Juan Fernández Islands ( Chile), L. ovata ( Poléjaeff, 1883) from Kerguelen Islands, L. pallida Row & Hôzawa, 1931 and L. thulakomorpha Row & Hôzawa, 1931 from Southwestern Australia and L. tropica Tanita, 1943 from Japan. Among these nine species, none has the same skeletal composition as L. quadriradiata sp. nov. ( Table 15). The new species can be easily differentiated from the others as it is the only Leucandrilla with chaonosomal and atrial skeletons exclusively composed of tetractines.

FAMILY HETEROPIIDAE DENDY, 1893