Rowella, Lopes & Klautau, 2023

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, Zoological Journal of the Linnean Society 198, pp. 691-746 : 715-716

GENUS ROWELLA GEN. NOV.

Z o o b a n k r e g i s t r a t i o n: h t t p s: / / z o o b a n k.o r g / urn:lsid:zoobank.org:act:5163DADD-AD0B-47B9-A595-369DACFA329C .

Type species: Leucettusa simplicissima Burton, 1932 .

Synonym: Leucetta – Poléjaeff, 1883: 28; non Haeckel, 1872: 117. Leucettusa – Dendy & Row, 1913: 738; Burton, 1963: 50; Borojević et al., 1990: 258; 2002: 1148; Hooper & Wiedenmayer, 1994: 481; Voigt et al., 2012: 11; Klautau et al., 2013: 454; Riesgo et al., 2018: 835.

Etymology: Named after Dr Harold Row for his efforts on the systematics of calcareous sponges and for being the co-author of Leucaltidae .

Diagnosis: Leucettidae with an amorphous or tubular massive body.The well-developed cortical skeleton can be comprised of single or multiple layers of triactines and/ or tetractines. The choanosomal and the atrial skeletons are comprised of pygmy triactines and tetractines. Aquiferous system leuconoid, syconoid or both.

Remarks: Most of the species here assigned to RoƜella have a tubular body but several others can grow ramifications (e.g. R. simplicissima ), while some have a pyriform or amorphous shape (e.g. R. pyriformis and R. dyctiogaster ). More than the external morphology, every member of this genus has a peculiar spicule category, named primarily as pygmy triactines and/ or tetractines by Poléjaeff (1883: 67). These spicules are present in the choanosomal and atrial regions, in different proportions among species. We opt to follow Poléjaeff’s termination and refer to these spicules as pygmy in our descriptions. It is important to highlight that Leucaltis and RoƜella were not recovered as sister-taxa. Hence, pygmy spicules are different from the small choanosomal and atrial spicules of Leucaltis , differing from what was previously thought (e.g. Borojević et al., 1990). Pygmy spicules may have even a reduced actine (assuming a V-shape). As Poléjaeff (1883) just called them pygmy, not defining them, we are defining them by their size range (from 10.0–83.0 μm length to 2.5–13.0 μm width) and location scattered in the choanosomal and atrial skeletons. The presence of these morphological traits should be considered in the diagnosis of the genus.

We could not resolve doubts on Leucettusa soyo ( Hôzawa, 1933) . This species had its position questioned in previous works (e.g. Dendy & Row, 1913; Rapp, 2004; Cavalcanti et al., 2013) and was allocated in different calcinean genera. Hôzawa’s (1933) description is doubtful, because important morphological characters, such as the presence of anastomosed tubes, were not clearly mentioned. He described a massive sponge, with radial choanocyte chambers around the atrium. Yet, he also mentioned the presence of ‘ascon-tubes’ and described the aquiferous system as ‘Dendy’s type D’ ( Dendy, 1891), i.e. solenoid ( Cavalcanti & Klautau, 2011). This is the only description available for this species and it is not satisfactory for its identification. We consider this a case of species inquirenda and highlight Cavalcanti et al. ’s (2013) statement that its position is uncertain and new material is necessary to make a proper genus assignment.

Scope: Ten previously described ‘ Leucettusa ’ species are being transferred to the new genus RoƜella : R. connectens ( Brøndsted, 1926) ; R. dictyogaster ( Row & Hôzawa, 1931) ; R. haeckeliana ( Poléjaeff, 1883) ; R. imperfecta ( Poléjaeff, 1883) ; R. lancifera ( Dendy, 1924) ; R. mariae ( Brøndsted, 1926) ; R. pyriformis (Brønsted, 1926) ; R. simplicissima ( Burton, 1932) ; R. tubulosa ( Dendy, 1924) and R. Ʋera ( Poléjaeff, 1883) . Leucettusa nuda ( Azevedo et al., 2009) is considered a junior synonym of R. simplicissima . Leucettusa soyo ( Hôzawa, 1933) is considered species inquirenda.