Description

Remarks: Due to the small size of the type specimen (<1 cm), it could not be loaned, and microscope slides could not be prepared by the current staff of the Stazione Zoologica Anton Dohrn di Napoli (Andrea Travaglini, personal communication). Nevertheless, based only on the original description, we figured out that (1) important characters typical of Amphoriscus were not reported along the description of this species, such as the syconoid aquiferous system and the inarticulate skeleton formed by the apical actines of the cortical tetractines and the unpaired actine of the subatrial spicules; and (2) the shape of the small atrial tetractines, of which “ la forma è molto caratteristica ” (Sarà 1960), suggesting that they are pugioles. These spicules correspond to small harpoon — (or dagger-) shaped spicules present in the order Baerida (Borojevic et al. 2002; Alvizu et al. 2018, 2019). Besides the presence of pugioles, the description provided by Sarà (1960) contains other characters found in the definition of Baerida: the presence of cortical large and giant spicules (triactines and tetractines, respectively, in the case of A. dohrni), and the presence of microdiactines abundant in the atrial skeleton (although it is not clear if they are more abundant than the atrial pugioles). Therefore, based on these features, there is no support for keeping the species inside the genus Amphoriscus, and we propose to transfer it to Baerida. According to Van Soest et al. (2021), Baerida is formed by four families: Baeriidae Borojevic, Boury-Esnault & Vacelet, 2000, Petrobionidae Borojevic, 1979, Trichogypsiidae Borojevic, Boury-Esnault & Vacelet, 2000, and Lepidoleuconidae Vacelet, 1967. Among the families mentioned above, only Baeriidae and Petrobionidae include pugioles in their composition (Borojevic et al. 2002; Alvizu et al. 2019). Petrobionidae has a basal calcareous skeleton of calcite. This family is monotypic, and Petrobiona massiliana Vacelet & Lévi, 1958 does not resemble “ A ”. dohrni, in which the basal skeleton is absent (Borojevic et al. 2002). Baeriidae includes four genera: Leuconia Grant, 1833, Eilhardia Poléjaeff, 1883, Lamontia Kirk, 1895, and Leucopsila Dendy & Row, 1913. However, only Leuconia and possibly Lamontia are pugiole-bearing genera. The latter is characterised by having diactines perforating the cortex and microdiactines throughout the choanoskeleton, characters that were not reported for “ Amphoriscus ” dohrni (Sarà 1960; Borojevic et al. 2002). Since this species does have atrial pugioles, we decided to allocate it within Leuconia ¸ despite the absence of sagittal triactines in the atrium. We therefore highlight the need for a taxonomic revision of Leuconia and the entire order Baerida, echoing recent suggestions from Alvizu et al. (2018, 2019).

Common Names

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Porifera

Class: Calcarea

Order: Baerida

Family: Baeriidae

Genus: Leuconia

Species: Leuconia dohrni (Sarà, 1960)