LEUCALTIS CLATHRIA HAECKEL, 1872 (FIGS 4, 5; TABLE 1) Synonyms: Artynas clathria – Haeckel, 1872: 159. Leucaltis clathria – Haeckel, 1872: 159; Arndt, 1941: 46; Burton, 1963: 598; Borojević & Peixinho, 1976: 1002; Borojević et al., 2002: 1148; Dohrmann et al., 2006: 832; Muricy et al., 2008: 131; Lanna et al., 2009: 13; Muricy et al., 2011: 35; Klautau et al., 2013: 449; Van Soest & De Voogd, 2015: 43; Cóndor-Luján & Klautau, 2016: 232; Van Soest, 2017: 198, Cóndor-Luján et al., 2018: 61; Fontana et al., 2018: 354; Lopes et al., 2018a: 59; 2018b: 139; non Dendy, 1913: 16; Leucetta clathria – Poléjaeff, 1883: 29; Heteropegma nodus gordii – Poléjaeff, 1883: 45 (in part, Bermuda material only); Heteropegma nodus-gordii – Hanitsch, 1895: 209; Amphoriscus nodusgordii – Breitfuss, 1898: 90; Leucaltis sp. – Thacker et al., 2013: 385. Type specimen: Fragment (MNHN. LBIM. C 1968.667) and slides (BMNH 1956.4.26.42) of Haeckel’s specimen used in the original description (holotype). Type locality: Florida, United States of America (27°54ʹ N, 80°01ʹ W; inaccurate coordinates). Floridian ecoregion. Description: Sponge body tubular and repent with some anastomosis (Fig. 4A, B). The anastomosis is variable; it can be loose and sparse or dense, with tubes closely attached to each other. Tubes are mostly cylindrical, but commonly compressed in few parts, giving the body a folded appearance. Consistency harsh to the touch, relatively firm and friable. Colour white or pink in life and white, beige to light brown or pink after fixation (Fig. 4A, B). Outer surface smooth. Body wall thin (Fig. 4C). Atrial cavity wide and spacious. Atrial surface slightly hispid due to the apical actines of cortical and atrial tetractines. Oscula are few, simple circular apertures without ornamentation (Fig. 5A). The aquiferous system represents the new type, kladonoid, with choanocyte chambers mostly elongated and ramified, commonly these ramifications fuse with each other (Fig. 4C). Skeleton: The oscular margin has a transitional skeleton comprised of large sagittal triactines and tetractines, gradually becoming regular as the body wall thickens. Cortical skeleton well developed, with several layers of tangential triactines and tetractines (Fig. 4D). Choanosomal skeleton reduced, with many regular triactines and tetractines sparse around the canals (Fig. 4E). Excurrent canals and atrial skeleton comprised of sagittal triactines and tetractines, lying tangentially, with the apical actines pointing into the atrial cavity (Fig. 4F).

Published as part of Lopes, Matheus Vieira & Klautau, Michelle, 2023, Phylogeny and revision of Leucaltis and Leucettusa (Porifera: Calcarea), with new classification proposals and description of a new type of aquiferous system, pp. 691-746 in Zoological Journal of the Linnean Society 198 on page 699, DOI: 10.1093/zoolinnean/zlad008, http://zenodo.org/record/7894159