The Hydroids of the Scottish National Antarctic Expedition / by James Ritchie ; communicated by W.S. Bruce.

Bruce, William S.; Ritchie, James C.

doi:10.5962/bhl.title.46272

Cited by 3 publications

(12 citation statements)

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“…With a shared location and morphology, it seems likely that the ‘chain’ shares functional homology too, with the units demarcating the branchial openings in Lasanius , as previously proposed (e.g. Kiaer 1924; Simpson 1926; Stetson 1927; Ritchie 1963).…”

Section: Discussionsupporting

confidence: 58%

“…4C, D). The presence of a dark C ring around the paired optic region may support hypotheses inferring a cartilaginous sclerotic ring (see Ritchie 1963 and Van der Brugghen 2010). Yet, differentiation between pigmentation and cartilage can be problematic without further analyses (e.g.…”

Section: Discussionmentioning

confidence: 57%

“…1956). The scutes of Lasanius may also have provided a defensive weapon against predators, such as large eurypterids that shared their habitats (Ritchie 1963; Lomax et al . 2011), but this does not preclude other potential uses, such as hydrodynamic stabilizing similar to a true dorsal fin (Webb 1984; Fish et al .…”

Section: Discussionmentioning

confidence: 99%

“…While Ritchie included L . ‘ altus ’ throughout his PhD thesis (Ritchie 1963) it was with reference to more detailed work by Dr I. C. Smith from the University of Glasgow in 1958. This work consisted of a restudy of Lasanius , and also established L .…”

Section: Methodsmentioning

confidence: 99%

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Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

et al. 2023

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The fossil record of non-biomineralizing, softbodied taxa is our only direct evidence of the early history of vertebrates. A robust reconstruction of the affinities of these taxa is critical to unlocking vertebrate origins and understanding the evolution of skeletal tissues, but these taxa invariably have unstable and poorly supported phylogenetic positions. At the cusp between mineralized bony vertebrates and entirely soft-bodied vertebrates is the enigmatic Lasanius, a purported anaspid from the Silurian of Scotland. Interpretations of its affinity and significance are conflicted, principally because of its poorly understood anatomy due to taphonomic distortion and loss of soft-tissues. Here we use an array of modern techniques to reassess the anatomy of Lasanius via a comprehensive study of 229 complete and partial specimens. A new reconstruction clarifies the identity and position of preserved features, including paired sensory organs, a notochord, and digestive tract, supporting the vertebrate affinities of this genus. SEM-EDS trace element mapping suggests a bone-like composition of mineralized parts, but finds no evidence for mineralized dermal armour. Phylogenetic analysis recovers Lasanius as an early stem-cyclostome, and subsequent analysis supports the rejection of alternative placements (such as stemgnathostome). We highlight that while distinguishing between the early cyclostome and gnathostome condition is problematic, increasing confidence in the anatomy of key taxa, such as Lasanius, is vital for increased stability throughout the early vertebrate tree.

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Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

et al. 2023

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“…Elsewhere.-Some (dubious) records from S Atlantic islands, NW Atlantic, South Africa and Pacific (Ritchie 1907(Ritchie , 1909Fraser 1944;Ralph 1961;Vervoort 1972;Park & Rho 1986;Hirohito 1995).…”

Section: Family Sertulariidae Lamouroux 1812mentioning

confidence: 99%

The hydrozoan fauna (Cnidaria: Hydrozoa) from the peaks of the Ormonde and Gettysburg seamounts (Gorringe Bank, NE Atlantic)

Moura

2015

Zootaxa

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Twenty-seven species of hydroids were collected from the peaks (35-42 meters depth) of the Gorringe Bank (NE Atlantic) during the oceanographic campaign 'LusoExpedição Olympus 2008'. Twenty-one of these species are new for the Gorringe Bank that now has published records for a total of 37 hydroid species. Lafoeina tenuis, Sertularella ellisii and Clytia hemisphaerica were the most abundant hydroid species collected. Results revealed spatial differences in the composition of species assemblages along the summits of the Gorringe, as only 14 of the species sampled were found both in the Ormonde and Gettysburg seamounts. The large density of algae at the peaks of the seamounts sustain a considerable hydrozoan diversity (23 species), but visibly inhibits the establishment of hydroids to the rocky substrates (only 2 species found). All the known hydrozoan species from the peaks of the Gorringe were exclusively collected during summer, thus sampling in other seasons may reveal further hydrozoan diversity due to seasonal patterns of growth of algae and hydroids. Nevertheless, the reasonably high levels of hydrozoan biodiversity demonstrated only from a small portion the summits of the Gorringe, corroborate its seamounts as 'biodiversity hotspots'. In agreement with previous investigations with shallow-water molluscs and sponges, the shallow-water hydroid fauna of the Gorringe revealed greater biogeographical affinities with the Mediterranean and mainland Portugal. This is the first report of Eudendrium armatum outside of the Mediterranean.

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Antarctic hydroids (Cnidaria, Hydrozoa) of the families Campanulinidae, Lafoeidae and Campanulariidae from recent Antarctic expeditions with R.V.Polarstern, with the description of a new species

Cantero

Svoboda

Vervoort

2004

Journal of Natural History

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Species of the thecate hydroid families Campanulinidae, Campanulariidae and Lafoeidae have been studied. The material studied originates from the Weddell Sea and was collected by several French and German Antarctic expeditions with R.V. Polarstern. Fourteen species were found, three belonging to Campanulinidae, four to Campanulariidae and seven to Lafoeidae, one of these new to science (Filellum magnificum sp. nov.). The coppinia of Lafoea gaussica Vanhö ffen, 1910, is described for the first time as well as the gonothecae of Opercularella belgicae (Hartlaub, 1904). A neotype is indicated for Filellum antarcticum (Hartlaub, 1904). Available data concerning autecology and geographical distribution for each species are given, as well as a description and figures when considered necessary.

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The Hydroids of the Scottish National Antarctic Expedition / by James Ritchie ; communicated by W.S. Bruce.

Cited by 3 publications

References 0 publications

Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

The hydrozoan fauna (Cnidaria: Hydrozoa) from the peaks of the Ormonde and Gettysburg seamounts (Gorringe Bank, NE Atlantic)

Antarctic hydroids (Cnidaria, Hydrozoa) of the families Campanulinidae, Lafoeidae and Campanulariidae from recent Antarctic expeditions with R.V.Polarstern, with the description of a new species

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