Aspiculortis garifuna, Ruiz & Ereskovsky & Perez, 2022

Ruiz, Cesar, Ereskovsky, Alexander & Perez, Thierry, 2022, New Skeleton-Less Homoscleromorphs (Porifera, Homoscleromorpha) From The Caribbean Sea: Exceptions To Rules Are Definitely Common In Sponge Taxonomy, Zootaxa 5200 (2), pp. 128-148 : 132-133

Aspiculortis garifuna sp. nov.

Etymology: The genus name Aspiculortis refers to the absence of skeleton and to the genetic proximity of Plakortis . The species name garifuna honors the ethnical and cultural diversity of the Garifuna people, descendants of the first Caribs, Arawak Amerindians and the African people who inhabited the Lesser Antilles.

Diagnosis: Thick crust (about 5 mm thick) with irregular form. No spicules, nor fibrous skeleton. The surface is covered by ostia with a series of translucent canals ending in prominent oscula of about 2 mm diameter. One type of vacuolar cell abounds in the ectosome and is also present in the mesohyl.

Examined material: Holotype: Muséum National d’Histoire Naturelle de Paris , France MNHN DJV202 Martinique, “Grotte Fer à Cheval” (14°27.832’N, 61°01.065’W), 19 m depth, on a vertical wall in the semi-dark section of the cave, date 25/03/2012, sample code: 120325 MT4 b-TP6, collector: T. Pérez. Genbank accession number: MK 949483

Paratype: Muséum National d’Histoire Naturelle de Paris , France MNHN DJV203 Guadeloupe, “Grotte aux Barracudas” (16°27.301’ N, 61°32.253’ W), 19 m depth, on a vertical wall in the semi-dark part of the cave, date 30/05/2015, sample code: 150530GU5-CR6, collector: C. Ruiz. Genbank accession number: MK 949485

Other material examined: Bequia , The Grenadines “Full Moon Cave” (12°59.525’ N, 61°16.731’ W), 10-12 m depth, beneath an overhang, date 19/05/2015, sample code: 150519LG1-CR14, collector: C. Ruiz. Genbank accession number: MK 949484

Martinique, “Grotte Zeb” (14°27.832’N, 61°01.065’W), 19 m depth, on a vertical wall in the semi-dark section of the cave, date 11/06/2011, sample code: 110613 MT4 -TP3, collector: T. Pérez. Genbank accession number: MK 949482

Martinique, “Grotte Zeb” (14°27.832’N, 61°01.065’W), 19 m depth, on a vertical wall in the semi-dark part of the cave, date 11/06/2011, sample code: 110613 MT4 -TP8, collector: T. Pérez .

Martinique, “Grotte Zeb” (14°27.832’N, 61°01.065’W), 19 m depth, on a vertical wall in the semi-dark part of the cave, date 15/05/2015, sample code: 150515 MT4 -CR1, collector: C. Ruiz.

Martinique, “Grotte Zeb” (14°27.832’N, 61°01.065’W), 19 m depth, on a vertical wall in the semi-dark part of the cave, date 16/05/2015, sample code: 160515 MT4 -CR9, collector: C. Ruiz.

Comparative material examined: Aspiculophora madinina Ruiz, Muricy, Lage, Domingos, Chenesseau & Pérez 2017 , Martinique, “Grotte Zeb” (14°27.832’N, 61°01.065’W), 19 m depth, on a vertical wall in the semi-dark section of the cave, date 16/05/2015, sample code: 160515 MT4 -CR10, collector: C. Ruiz.

Plakina nathaliae ( Ereskovsky et al. 2014) , Saint Martin, “Basses Espagnoles” (18°07.821’N, 63°00.270’W), 15 m depth, beneath an overhang, date 27/05/2015, sample code: 270515SN5-TP01, collector: T. Pérez .

Oscarella zoranja Pérez & Ruiz, 2018 , Martinique, Rocher du Diamant , “Grotte Zeb” (14°27.832’N, 61°01.065’W), 19 m depth, on a vertical wall in the semi-dark section of the cave, date 16/05/2015, sample code: 150516 MT4 -CR05, collector: C. Ruiz.

Oscarella filipoi Pérez & Ruiz, 2018 , Saint Lucie, “Anse Chastenet reef” (13°51.848’ N, 61°04.729’ W), 15 m depth, beneath an overhang, date 22/05/2015, sample code: 150522SL1-CR05, collector: C. Ruiz.

Description:

External morphology: Aspiculortis garifuna sp. nov. has an encrusting irregular form and a brown color in vivo and after fixation in ethanol. The largest specimen recorded measured 10 cm in diameter. This sponge is quite fragile. The smooth surface is pseudo-criblate, that it is to say covered by numerous ostia diverging soon under the epidermal surface in various inhalant canals. The sponge surface also presents a series of larger translucent exhalant canals ending in prominent oscula of about 2 mm in diameter. This dense network can appear contracted in some specimens ( Figure 2 A-B).

Internal Anatomy: No spicule nor fibrous skeleton. The ectosome is 40-60 µm thick ( Figure 2 C-D). The aquiferous system is leuconoid. Inhalant canals are 10-15 µm wide, running perpendicular to the surface. Choanocyte chambers (15-33 µm in diameter) are diplodal, spherical to ovoid ( Figure 2E ). The proportion between mesohyl and choanocyte chambers is greater than 1.

Cytology: Choanocytes are cylindrical, 5 µm wide and 7 µm high. Their nucleus is spherical (2 µm diameter) in apical position, their cytoplasm usually contains osmiophilic inclusions and vacuoles of about 2-3 µm in diameter that often harbor phagocytized bacteria ( Figure 3A ). The exo- and endopinacocytes are flagellated and flattened (12- 19 µm long; 3-4 µm wide) with several vacuoles and osmiophilic inclusions. The external surfaces of the exo- and endopinacocytes are covered with a double-layer of 0.5 µm thick glycocalyx ( Figure 3B ).

One type of vacuolar cell is found in abundance in the ectosome, and to a lesser extent in the mesohyl. This irregular shaped-cell, 10 x 20 µm in dimension, harbors 2-4 translucent vacuoles which are 3 to 8 µm in diameter ( Figure 3C ) and which often contain dense or loose heterogeneous material ( Figure 3D ). No archaeocyte was observed. There is a high abundance of prokaryotic symbionts in the mesohyl, with at least five dominant morphotypes randomly distributed throughout the mesohyl ( Figure 3E ). The first morphotype is an ovoid cell 2 - 4 µm long, 2.5 – 3 µm wide with a clear cytoplasm. The second morphotype has the same ovoid shape and size but has a denser cytoplasm. The third morphotype is an irregular cell shape which is 2 – 4 µm long and about 1 – 2.5 µm wide. The fourth morphotype is bean-shaped, 2.5 - 3 µm long and about 0.5 wide. The fifth morphotype is circular with a diameter of about 0.5 µm.

Ecology: This new sponge has been collected in the Caribbean islands (Lesser Antilles) of Guadeloupe, Martinique and Bequia. In all sites, this sponge inhabits vertical walls and ceilings of dark marine caves, located at depths between 10 and 25 m, in syntopy with several other Homoscleromorpha species. No sign of predation was observed. Serpulidae worms live in close association and are often observed living among the new sponge species ( Figure 2B ).

Taxonomic remarks: Aspiculortis garifuna gen. nov. sp. nov. has an encrusting form, as do most of the cave-dwelling Homoscleromorpha. It clearly belongs to a well-supported clade gathering Plakortis species, but its pseudo-criblate surface is unique, and thus has never been observed in Plakortis . The lack of cytological description of Caribbean Plakortis did not allow any comparison with the cells content of the new sponge. The absence of skeleton and this original pseudo-criblate surface justify the creation of a new genus. The new sponge also clearly differs from the other skeleton-less Plakinidae by its external morphology and internal organization, particularly the proportion between mesohyl and choanocyte chambers and the low abundance of symbiotic microorganisms in the thinly encrusting Plakina nathaliae , and the thick collagen layer found in the ectosome of the massive Aspiculophora madinina , as well as its aphodal choanocyte chambers.

Figures

FIGURE 2. A, B. In situ photos of Aspiculortis garifuna sp. nov. of two color morphotypes, with a mostly contracted surface (A), and the pseudo-criblate surface (B). C. Light microscopy micrograph of the internal organization of A. garifuna. D. Detailed view of the ectosome showing concentration of vacuolar cells. E. Detailed view of the choanosome showing two choanocyte chambers and the sylleibid-like aquiferous system. cha, choanocyte chambers; ec, ectosome; pin, pinacocytes; pk, prokaryotes; vc, vacuolar cell.

FIGURE 3. TEM micrograph of Aspiculortis garifuna sp. nov. A. Detailed view of a choanocyte chamber: choanocytes have their nucleus in apical position.Some prokaryotesare phagocyted by choanocyte vacuoles.B. Detailed view of an endopinacocyte with a typical flat shape, surrounded by a thick glycocalyx layer. C, D. Vacuolar cells. E. Micrograph showing morphological diversity of prokaryotes inside the mesohyl of A. garifuna. cho, choanocyte; gly, glycocalyx layer; pk, prokaryotes; vc, vacuolar cell. Numbers from 1 to 5 represent different morphotypes.