Leucaltis clathria Haeckel, 1872

(Figures 11–12, Table 11)

Synonyms. Artynas clathria: Haeckel 1872: 159, Heteropegma nodusgordii: Poléjaeff 1883: 45, Hanitsch 1895: 209. Leucaltis clathria: Haeckel 1872: 159, Dendy 1913: 16, Arndt 1940: 46, Borojevic & Peixinho 1976: 1002, Borojevic 1998: 75, Borojevic et al. 2002: 1148, Muricy et al. 2008: 131, Lanna et al. 2009: 13, Muricy et al. 2011: 35, Klautau et al. 2013: 449, Van Soest 2017: 198, Cóndor-Luján et al. 2018: 61.

Material Examined. (One specimen) UFRJPOR 7671, Le Rocher du Diamant, Martinique (14°26.556' N – 61°2.408' W), collected by F. Azevedo, 25 April 2015, 18.8 m depth.

Colour. Light pink alive and white in ethanol.

Description. Sponge formed by anastomosed tubes with apical oscula and central atrium (Figures 11A–B). Each tube has a cortex and atrium. Consistency firm, friable and rough to the touch. Elongated choanocitary chambers. The analysed specimen has many larvae in the choanosome (Figure 11C).

Skeleton. The cortical skeleton is composed of giant triactines and tetractines (Figure 11D). The apical actine of the tetractines crosses the choanosome and penetrates the atrium, which becomes hispid (Figures 11D–E). The sagittal spicules are mainly found surrounding the canals and the atrium (Figure 11F). The choanosome is also composed of very small regular and sagittal triactines and tetractines (Figure 11G).

Spicules (Table 11).

Triactine I: Regular. Very variable in size. Actines are conical with sharp tips (Figure 12A). Size: 330.0– 720.0/40.0–75.0 µm.

Tetractine I: Regular. It is similar to triactine I, but larger and thicker (Figure 12B). The apical actine of the tetractines is conical, large, thick, straight, smooth with a sharp tip (Figure 12C). Size: 420.0–900.0/40.0–120.0 µm.

Triactine II: Regular or sagittal. Actines are cylindrical, with blunt or rounded tips (Figures 11F, 12D). Size: 52.5–65.0/2.5–5.0 µm (regular), 30.0–67.5/2.5–5.0 µm (sagittal, unpaired actine), 57.5–70.0/2.5–5.0 µm (sagittal, paired actines).

Tetractine II: Regular or sagittal. Actines are cylindrical with blunt or rounded tips (Figures 11F, 12E). Size: 30.0–62.5/2.5–3.7 µm (regular), 32.5–52.5/2.5–5.0 µm (sagittal, unpaired actine), 37.5–72.5/2.5–5.0 µm (sagittal, paired actine).

Ecology. The analysed specimen was collected at the entrance of a cave, in a shaded environment. No epibionts were found.

Geographical distribution. Atlantic Ocean: U.S.A. Florida (Haeckel 1872), off Bermuda (Poléjaeff 1883), Panama (Klautau et al. 2013), Portugal (Hanitsch 1895; Arndt 1940), Guyana Shelf (Van Soest 2017), Brazil— Pará State, Alagoas State, Ceará State, Rio Grande do Norte State, Sergipe State, Espírito Santo State (Borojevic & Peixinho 1976; Muricy et al. 2008; 2011, Lanna et al. 2009).

Remarks. For a long time, Leucaltis clathria was considered to be a cosmopolitan species (Poléjaeff 1883; Carter 1886; Dendy 1892, 1893, 1905; Borojevic 1998, Borojevic & Klautau 2000). However, in 2013 Klautau et al. generated DNA sequences of L. clathria from the Caribbean Sea (type locality of this species) and from Australia, and suggested that the specimens from Australia comprised a distinct species. In 2015, Van Soest & De Voogd published a work about calcareous sponges from Indonesia and proposed that Indo-Pacific specimens morphologically similar to L. clathria should be called L. nodusgordii (Poléjaeff, 1883) . Therefore, L. clathria is currently considered to be present only in the Atlantic Ocean, having an amphi-Atlantic distribution.