A new leptomitid-like sponge from the Early Ordovician of China with heteractinid spicules

Botting, Joseph P.; Zhang, Yuandong

doi:10.3140/bull.geosci.1361

Cited by 8 publications

(8 citation statements)

References 13 publications

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“…Traditionally considered to be a group of primitive demosponges, the large‐spiculed protomonaxonids are now recognized as an earlier‐branching lineage of either Silicea or Porifera (Botting et al . , ; Botting & Zhang ), rather than crown‐ or stem‐group Demospongiae.…”

Section: Systematic Palaeontologymentioning

confidence: 99%

Early Cambrian sponges of the Sirius Passet Biota, North Greenland

Botting

Peel

2016

Papers in Palaeontology

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The Sirius Passet Biota of the Buen Formation in North Greenland is one of the key Burgess Shale‐type faunas, as it represents the only diverse early Cambrian (Stage 2, Series 3) biota from Laurentia. The sponges are one of the major components of the fauna, although they appear to be much less abundant than arthropods, based on the available collections. At least 13 species are described here, including the new taxa Hamptonia limatula sp. nov., Lenica perversa sp. nov., Saetaspongia procera sp. nov., Constellatispongia canismajorii gen. et sp. nov. and Crassicoactum cucumis gen. et sp. nov. An additional new species, Ratcliffespongia freuchenensis sp. nov., is described from the upper part of the Buen Formation. The assemblage is dominated by a major lineage of protomonaxonids, together with rarer reticulosans and demosponges. Some taxa, such as the anthaspidellid lithistid Fieldospongia bellilineata, were previously known only from Laurentian faunas; others, such as Saetospongia densa, Solactiniella cf. plumata and Lenica unica, were previously recognized from South China and/or Siberia. The described assemblage confirms the cosmopolitan distribution of Cambrian sponges generally, and suggests that the differences between Laurentian and Chinese assemblages are due more to a taxonomic overturn during Cambrian Series 2, Stage 4, than to the geographical separation. Furthermore, crown‐group demosponges appear to have occupied shallow‐water (perhaps dominantly platform) environments at this time, and may have been much more diversified and widespread than is currently recognized during the early Cambrian.

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Section: Systematic Palaeontologymentioning

confidence: 99%

Early Cambrian sponges of the Sirius Passet Biota, North Greenland

Botting

Peel

2016

Papers in Palaeontology

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“…8 morphology. Alternatively, an Ordovician sponge (Botting and Zhang, 2013) suggests that the Leptomitidae were derived from a related, but slightly separated branch of hexactine-bearing sponges that possessed both longitudinal and transverse monaxons, and also heteractine (pentaradiate and triradiate) spicules. The precise origin of this family therefore remains uncertain, and they may originate from a deep division within the protomonaxonids, or from a separate region of either the poriferan or a class-level stem group.…”

Section: Group One Protomonaxonidsmentioning

confidence: 99%

Relationships of the Cambrian Protomonaxonida (Porifera)

Botting

Muir

Lin

2013

Palaeontologia Electronica

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The Protomonaxonida consist of a heterogeneous group of early fossil sponges traditionally assigned to the demosponges. However, an affinity to the hexactinellid-like Reticulosa has also been suggested, and their relationships are potentially critical to understanding the origins of the extant sponge classes. In this paper, the relationships of the protomonaxonid sponges to each other and to other sponge groups have been reassessed, using previously described specimens as well as new material from the Burgess Shale of Canada and the Hetang Biota of South China. The sponges fall into two coherent groups, one consisting of taxa with long, mostly sub-longitudinal spicules, and the other with complex arrays composed of tracts of minute (millimetre-scale) monaxons, which grade into aspiculate taxa such as the Vauxiidae. Previous ideas relating the Protomonaxonida to extant demosponge lineages are supported in the case of the second group, whereas the first group confirms the view of derivation from a hexactinellid-like ancestor. Whether the two groups were directly related or evolved monaxonid spiculation in parallel is currently uncertain.

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“…However, as discussed under the systematic paleontology, the family Protospongiidae currently includes genera with diverse morphologies, some with regularly arranged and ranked stauractines forming regularly nested quadrules, others with irregularly arranged and poorly ranked stauractines forming local sub-quadrules, and still others that may not have quadrules or stauractines (e.g., Quadrolaminiella and Saetaspongia). Thus, although the Protospongiidae has been traditionally classified in the class Hexactinellida (Finks et al, 2004;Carrera and Botting, 2008), it is possible that this family as currently defined may be paraphyletic and may include both hexactinellids and stemgroup siliceans, particularly if hexactine-based spicules are not a unique feature of hexactinellids (Botting and Butterfield, 2005;Botting and Zhang, 2013;Botting et al, 2014a). A more thorough systematic evaluation of this family may result in its breakup into several families.…”

Section: Discussionmentioning

confidence: 94%