Surface Microornamentation of Demosponge Sterraster Spicules, Phylogenetic and Paleontological Implications

Abstract

Siliceous spicules in demosponges exist in a variety of shapes, some of which look like minute spheres of glass. They are called “sterrasters” when they belong to the Geodiidae family (Tetractinellida order) and “selenasters” when they belong to the Placospongiidae family (Clionaida order). Today, the Geodiidae represent a highly diverse sponge family with more than 340 species, occurring in shallow to deep waters worldwide, except for the Antarctic. The molecular phylogeny of Geodiidae is currently difficult to interpret because we are lacking morphological characters to support most of its clades. To fill this knowledge gap, the surface microornamentations of sterrasters were compared in different genera. Observations with scanning electron microscopy revealed four types of surfaces, which remarkably matched some of the Geodiidae genera: type I characteristic of Geodia, type II characteristic of Pachymatisma, Caminus, and some Erylus; type III characteristic of other Erylus; type IV characteristic of Caminella. Two subtypes were identified in Geodia species: warty vs. smooth rosettes. These different microornamentations were mapped on new Geodiidae COI (Folmer fragment) and 28S (C1–D2) phylogenetic trees. The monophyly of the Geodiidae was once again challenged, thereby suggesting that sterrasters have evolved independently at least three times: in the Geodiinae, in the Erylinae and in Caminella. Surface microornamentations were used to review the fossil record of sterrasters and selenasters through the paleontology literature and examination of fossils. It was concluded that “rhaxes” in the literature may represent mixes of sterrasters and selenasters: while Rhaxella spicules may belong to the Placospongiidae, Rhaxelloides spicules belong to the Geodiidae. The putative Geodiidae fossil genera, Geoditesia, and Geodiopsis, are reallocated to Tetractinellida incertae sedis. Isolated Miocene-Pliocene fossil sterrasters Hataina (Huang, 1967), Silicosphaera (Hughes, 1985) and Conciliaspongia (Robinson and Haslett, 1995) become junior synonyms of Geodia (Lamarck, 1815). Overall, the fossil record suggested that Geodiidae was present at least since the Middle Jurassic (163–166 Mya), while Geodia sterrasters were present since the Santonian/Campanian boundary, Late Cretaceous (83.6 Mya).ZooBank Article Registrationurn:lsid:zoobank.org:pub:91B1B3AC-8862-4751-B272-8A3BDF4DEE77.

Campanian (Late Cretaceous) Theonellidae and Phymaraphiniidae (lithistid Demospongiae) from the Miechów and Mogilno‐Łódź synclinoria (southern and central Poland): new data and taxonomic revision

“…Uriz 2002; Cárdenas et al . 2011, 2013; Cárdenas 2020) while acanthorhabds, pseudospherasters, microxeas, streptasters and amphiasters characterize extant Theonellidae (Pisera & Lévi 2002 a ). The supposed sterrasters illustrated by Hurcewicz (1966, pl.…”

Opoka – a mysterious carbonate-siliceous rock: an overview of general concepts

“…4C, D), led to the conclusion that the silica (opal-CT) present in opoka is biogenic and originates from spicule dissolution (Sujkowski 1931, Pożaryska 1952, Rutkowski 1965. Moreover, the stratigraphic distribution of opoka rocks correlates with periods of significant siliceous sponge development (Pisera 1999, Cárdenas 2020) and indicates that opoka formation is linked to the mass occurrence of siliceous sponges (Jurkowska & Świerczewska-Gładysz 2020a).…”

High diversity of siliceous sponges in Western Tethyan areas during the Eocene: palaeobiogeographical, ecological and taxonomic significance

“…Caminus Schmidt, 1862 and Pachymatisma Bowerbank in Johnston, 1842 (subfamily Erylinidae Sollas, 1888)), but in the majority of cases (nearly 95%) sterrasters belong to the genus Geodia (subfamily Geodiinae Sollas, 1888; compare with van Soest et al . 2012; Cárdenas 2020).…”

“…Spicules of extinct geodiid spicules have been recorded from various strata in many parts of the world (e.g. Wiedenmayer 1994), and sterrasters of Geodia first occur in upper Cretaceous strata (Cárdenas 2020). From the Cenozoic level, sterrasters have been described from Portugal (Pisera et al .…”