Mycale (Mycale) lorea Dinn, Ott, Marmen, Steeves, Côté, Hayes, Nozères, Everett, Powell & Chu, 2023, sp. nov.

Mycale (Mycale) lorea sp. nov. (Fig. 6 and Table 2) ZOOBANK LSID: urn:lsid:zoobank.org:act: 0C67A722-A22B- 4F48-8AE5-68CD2571D47A. DIAGNOSIS: Large vase-shaped sponge with dense, protruding, light yellow veining spicule tracts and a firm, thick stalk. Often collected as large fragments in trawl samples. MATERIALS EXAMINED: Holotype: CMNI 2022-0001, Gulf of St. Lawrence, SE of Anticosti Island, 48.829 ◦ N, 61.106 ◦ W, 211 m, collected by Fisheries and Oceans Canada, 17 August 2018. Paratypes: CMNI 2022-0002, southern Tail of the Bank, Newfoundland, 43.09 ◦ N, 49.518 ◦ W, 589 m, collected by Fisheries and Oceans Canada, 23 October 2012. CMNI 2022-0003, NL Shelf, west of southern Labrador, 52.167 ◦ N, 53.135 ◦ W, 220 m, collected by Fisheries and Oceans Canada, 4 December 2020. CMNI 2022-0004, west of the Flemish Cap, Newfoundland, 46.37 ◦ N, 47.0983 ◦ W, 770 m, collected by Fisheries and Oceans Canada, 16 January 2015. CMNI 2022-0005, Gulf of St. Lawrence, SW of Anticosti Island, 48.855 ◦ N, 61.162 ◦ W, 181 m, collected by Fisheries and Oceans Canada, 16 August 2018. CMNI 2022-0006, Gulf of St. Lawrence, NW of Anticosti Island, 49.926 ◦ N, 65.074 ◦ W, 160 m, collected by Fisheries and Oceans Canada, 25 August 2017. ADDITIONAL SPECIMENS EXAMINED: QC _ 2020_215, Gulf of St. Lawrence, W of Anticosti Island, 49.401 ◦ N, 59.948 ◦ W, 206 m, collected by Fisheries and Oceans Canada, 24 August 2020. Specimens from Bouchard Marmen et al. (2021): PAA2010009061246, Davis Strait, northeast of Clyde River Nunavut, 70.677 ◦ N, 66.811 ◦ W, 677 m, collected by Fisheries and Oceans Canada, 25 October 2010. PAA2010009067237, Davis Strait, southeast of Clyde River Nunavut, 70.090 ◦ N, 65.692 ◦ W, 467 m, collected by Fisheries and Oceans Canada, 26 October 2010. PAA2012007038033, Baffin Bay, eastern entrance to Lancaster Sound, 74.446 ◦ N, 78.432 ◦ W, 663 m, collected by Fisheries and Oceans Canada, 5 October 2012. PAA2012007037332, Baffin Bay, eastern entrance to Lancaster Sound, 74.612 ◦ N, 77.832 ◦ W, 442 m, collected by Fisheries and Oceans Canada, 5 October 2012. COMPARATIVE MATERIAL EXAMINED: Syntype: Esperella bellabellensis Lambe, 1905 CMNI 1994-0038 / CMNI 1994-0039, off Bella Bella, Campbell Island, British Columbia, 52.17 ◦ N 128.17 ◦ W, 549 m, collected by F. Landsberg, 1904. ETYMOLOGY: From the Latin lorea meaning a laurel branch, crown, or wreath. The distinctive light-coloured veining spicule tracts are diagnostic of the species and resemble the roots and branches of a bay laurel tree. EXTERNAL APPEARANCE (Figs. 6A and 6B): Large vase-shaped sponge with a thick stalk. The vase is bolstered by thick, protruding spicule tracts, which are lightly coloured and thickest on the outer surface of the vase. The interconnecting spicule tracts form an irregular lattice filled with softer tissue. Specimens are firm and difficult to tear; however, choanosomal tissue may be removed easily while spicule tracts stay intact. A presumed specimen was seen in situ during a benthic video survey in the Eastern Honguedo Strait Coral and Sponge Conservation Area in July 2022, with a distinct vase shape and visible light-coloured veining spicule bundles (Fig. 6B). SKELETON (Figs. 6C and 6D): The skeleton consists of a dense mesh of spicule tracts formed by densely packed styles. On the outer surface of the sponge, these tracts are especially thick and prominently lightly coloured, reaching from the stem to the outer fringe. Thin tissue is spread between the dense tracts, with a mostly confused arrangement of loose tracts of styles, with palmate anisochelae variably occurring in rosettes (Fig. 6D). Styles flare out into soft tissue as spicule brushes at the ends of the dense tracts (Figs. 6C and 6D). In heavily damaged and trawl-worn specimens, tissue containing chelae may not be abundant. SPICULES (Figs. 6E–6L and Table 2): From the holotype CMNI 2022-0001: Styles: 354– 397 –428 × 14– 17 –19 µm, generally straight, but some are slightly curved. The head of the spicule near the rounded end is thin, and the spicule thickens at about a quarter of its length, with the thickest portion near the midpoint. From the middle, styles gradually taper to a sharply pointed tip. In some specimens, thinner styles show a slightly pronounced rounded head, somewhat reminiscent of a subtylostyle. Some specimens may have styles with multiple swellings down the shaft, but this is uncommon. Large anisochelae: 56– 61 –64 µm, with well-developed and broad upper alae. The free portion of the shaft is short, at less than 1/5 of the total spicule length. The upper alae have a considerable width, which may be wider than half the length of the whole spicule. The lower alae have a straight upper rim. A rounded, tooth-like extension protrudes above the upper rim of the lower alae, arising from the centre. Medium anisochelae: 27– 34 –39 µm, have an overall elongated shape with the free part of the shaft variable in size, less than 1/5 of the length of the spicule. Lower alae also have a straight upper rim but no noticeable protrusions. Small anisochelae: 15– 19 –23 µm, also elongated and similar in overall shape to the medium size category; however, there is a median tooth-like extension arising from the lower alae along the upper rim. Medium and small anisochelae measurements from eastern Canadian Arctic specimens are combined into a single size category (Table 2) as these measurements were taken prior to SEM imagery confirmation of the three size categories of anisochelae (Bouchard Marmen et al. 2021). GENETIC DATA: COI, D13–E 13 28S, and ITS sequences were obtained for Mycale (Mycale) lorea sp. nov. The sequences of the three gene regions appear most similar to species from the genus Mycale based on a BLAST search. Maximum likelihood trees comparing available Mycale ITS and D13–E 13 28S sequences were constructed, which resulted in separate monophyletic clades for Mycale (Mycale) loveni and M. (M.) lorea sp. nov. (Figs. 4 and 5). As assembled COI sequences for M. (M.) loveni were not obtained, M. (M.) lorea sp. nov. could not be positively differentiated using this gene fragment. DISTRIBUTION AND ECOLOGY: Mycale (Mycale) lorea sp. nov. has a wide range in the western North Atlantic. Specimens from DFO catch databases have been collected from 114 to 1336 m depth. The species has been collected in the eastern Canadian Arctic, along the Newfoundland and Labrador Shelf, and in the northern Gulf of St. Lawrence (Figs. 1B and 1C). The species is also present on the Grand Banks of Newfoundland. This area includes both the southern extremity known as the Tail of the Bank and the Flemish Cap, areas outside of Canada’s exclusive economic zone (Fig. 1C). A presumed specimen was seen in situ at 334 m depth during a video survey of sea pen (Pennatula aculeata Danielssen, 1860; Balticina finmarchica (Sars, 1851)) fields in the Eastern Honguedo Coral and Sponge Conservation Area (DFO 2023) aboard the Coriolis II, living in a mud/silt bottom habitat attached to a rock showing the diagnostic vase shape and light-coloured veining formed by style bundles (Fig. 6B). From underwater video, the surrounding habitat in the conservation area was home to redfish (Sebastes spp.), Marlin-spike grenadier (Nezumia bairdii (Goode & Bean, 1877)), Norway king crab (Lithodes maja (Linnaeus, 1758)), and several sponge species, including Polymastia spp. From survey trawls in the northern Gulf of St. Lawrence, M. (M.) lorea sp. nov. was collected along with large catches of Atlantic Cod (Gadus morhua Linnaeus, 1758), Redfish (Sebastes spp.), Greenland halibut (Reinhardtius hippoglossoides (Walbaum, 1792)), white hake (Urophycis tenuis (Mitchill, 1814)), and northern shrimp (Pandalus borealis KrØyer, 1838). In shallower habitats (100–200 m depth), the sponge was collected alongside American plaice (Hippoglossoides platessoides (Fabricius, 1780)) and striped shrimp (Pandalus montagui Leach, 1814). The direct association of fish and invertebrate species with sponges cannot be inferred from these occurrences, and sponge catchability in trawls is low (Kenchington et al. 2011); therefore, the distribution of this species may be more widespread than is currently known. Both Atlantic and striped wolffish (Anarhichas lupus Linnaeus, 1758; A. minor Olafsen, 1772) also occurred in some captures of the sponge southeast of Anticosti Island, which is of particular interest as the former is listed under Canada’s Species at Risk Act as a species of special concern and the latter as a threatened species (Government of Canada 2002). Mycale (Mycale) lorea sp. nov. also co-occurs in trawl catches with other sponge species, notably Polymastia spp., Crella (Crella) cutis Goodwin, Dinn, Nefedova, Nijhof, Murillo, and Nozeres, 2021, and Plicatellopsis bowerbanki (Vosmaer, 1885) (Dinn et al. 2020 a; Goodwin et al. 2021). REMARKS: It has been suggested that megasclere size is a solid taxonomic character to distinguish closely related species (van Soest et al. 2021), and in the case of Mycale (Mycale) loveni and M. (M.) lorea sp. nov., the megascleres are not only different in size, but in shape as well. The styles are often longer than 450 µm and thickest near the point in M. (M.) loveni, and the styles in M. (M.) lorea sp. nov. are generally less than 450 µm in length and are thickest near the middle. A single specimen from the Gulf of St. Lawrence had many thinner styles, which were measured here as a second size category (Table 2); however, silica concentration in ambient water has also been suggested to affect spicule width (Stone 1970; Mercurio et al. 2000; Austin et al. 2014). Further, van Soest et al. (2021) state that differences in width are strongly influenced by the growth stage of the individual spicules and are not likely diagnostic. Although both species have three size categories of anisochelae, the size difference and shape difference between the species are obvious in light micrographs for most specimens. Note: n =

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.