The Late Cretaceous brittle star Ophiosmilax? alternatus from Europe and northern Africa

Štorc, Richard

doi:10.1016/j.geobios.2003.01.010

Cited by 4 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus the transspondyline vertebrae of Ophiolebes vivipara Djakonov, 1949, andOphiosmilax? alternatus Kutscher &Jagt, 2000, are intermediate between the hourglass type and the zygospondyline type (Litvinova 1989;Kutscher & Jagt 2000: 48;Štorc 2004). Only Litvinova (1989: 51) mentioned and included Onychaster in this trajectory; so we are also testing this inclusion.…”

Section: Discussionmentioning

confidence: 98%

Observations on Onychaster Meek & Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*

Hotchkiss¹,

Glass

2012

Zoosymposia

View full text Add to dashboard Cite

Onychaster is prominent in discussions on the ancestry of crown group ophiuroids because about half of researchers have classified Onychaster as a Palaeozoic representative of the living Order Euryalida. With this classification there is a Mississippian to Cretaceous gap in the euryalid fossil record. Other researchers have classified Onychaster as non-euryalid, in which case there is no such gap. This undecided status is an important reason to review the classification of Onychaster using new observations. In Onychaster the lateral plates are strictly on the underside of the arm where they form a double row and nearly touch midventrally; there are no mid-ventral underarm plates. The undersurface-laterals bear a transverse row of spines that point proximally (in retro-direction). The disk in large specimens bulges interradially such that the arms insert subambitally. The morphology of Onychaster vertebrae is documented anew in SEM stereo-pair images. Distinctive features include: a median dorsal cleft or circular pit on the upper surface; an auluroid canal; paired epanapophyses; a zygosphene dorsal to the auluroid canal; exceptionally spacious fossae for the ventral longitudinal muscles; and an undersurface plastron that is dimensioned like a waist belt. These features are transformationally close to eospondylid/furcasterid vertebrae and progressively/increasingly distant from zygospondylous, transpondylous, and streptospondylous vertebrae. Classification of Onychaster as an euryalid is not supported. We reclassify the Onychasteridae next to the Furcasteridae.

show abstract

Section: Discussionmentioning

confidence: 98%

Observations on Onychaster Meek & Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*

Hotchkiss¹,

Glass

2012

Zoosymposia

View full text Add to dashboard Cite

show abstract

“…The misconception of transspondylous vertebrae by Alitto et al (2020) may have been caused by vertebrae not being fully developed in incompletely regenerated animals after fission. Also, this type of vertebra is still only known from the fossil tentatively assigned to Ophiosmilax alternatus Kutscher & Jagt in Jagt, 2000 by Štorc (2004). The genus Ophiosmilax is a member of the family Ophiobyrsidae (order Ophiacanthida) and its type genus Ophiobyrsa Lyman, 1878 has streptospondylous vertebrae (B. Thuy, unpublished data), similar to Ophiocamax vitrea , a type common in Ophiacanthida.…”

Section: Discussionmentioning

confidence: 99%

“…For instance, in some families ( e . g ., Ophiotrichidae) epizoic taxa, habitually attaching to other surfaces, have vertebrae that closely resemble the euryalid streptospondylous shape (Alitto et al, 2020; Litvinova, 1989a), erroneously termed transspondylous by Alitto et al (2020), which however is a morphologically different type limited to the genus Ophiosmilax Matsumoto, 1915 (Štorc, 2004). We propose the term ‘semi‐streptospondylous’ instead.…”

Section: Introductionmentioning

confidence: 99%

“…(a) Anatomy of the vertebra in Ophiocoma scolopendrina (terminology partially adopted from Hotchkiss et al [2007]). (b) Schematic images of vertebral articular structures; zygospondylous based on Bray (1985), semi‐streptospondylous based on the Ophiothela image in Alitto et al (2020) (here renamed semi‐streptospondylous due to its different morphology from transspondylous), streptospondylus (euryalid) based on Mortensen (1933) and transspondylous based on Štorc (2004)…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The evolutionary relationship between arm vertebrae shape and ecological lifestyle in brittle stars (Echinodermata: Ophiuroidea)

et al. 2021

View full text Add to dashboard Cite

Ophiuroidea are one of the most diverse classes among extant echinoderms, characterized by their flexible arms composed of a series of ossicles called vertebrae, articulating with each other proximally and distally. Their arms show a wide range of motion, important for feeding and locomotion, associated with their epizoic and non‐epizoic lifestyles. It remains to be explored to what degree the phenotypic variation in these ossicles also reflects adaptations to these lifestyles, rather than only their phylogenetic affinity. In this study, we analyzed the 3D shape variation of six arm vertebrae from the middle and distal parts of an arm in 12 species, belonging to the intertidal, subtidal and bathyal zones and showing epizoic and non‐epizoic behaviors. A PERMANOVA indicated a significant difference in ossicle morphology between species and between lifestyles. A principal component analysis showed that the morphology of epizoic ophiuroids is distinct from non‐epizoic ones; which may reflect variation in arm function related to these different lifestyles. The Phylogenetic MANOVA and phylogenetic signal analysis showed that shape variation in the vertebral articulation seems to reflect ecological and functional adaptations, whereas phylogeny controls more the lateral morphology of the vertebrae. This suggests a convergent evolution through ecological adaptation to some degree, indicating that some of these characters may have limited taxonomic value.

show abstract

Operculate cyclostome bryozoans (Eleidae) from the Bohemian Cretaceous

Taylor

Zágoršek

2011

Paläontol. Z.

View full text Add to dashboard Cite

Eleidae ('melicerititids') are unusual cyclostome bryozoans possessing operculate zooids and mandibulate polymorphs ('eleozooids') resembling the avicularia of cheilostome bryozoans. Here we describe 13 eleid species from the Cenomanian-Turonian of the Bohemian Cretaceous basin in the Czech Republic. Three species of Meliceritites are new: Meliceritites kankensis, M. stillativa and M. upohlavyensis. Reptoforicula gen. nov. is introduced for free-walled eleids with multilamellar encrusting colonies, containing the type species Reptoforicula zbyslavensis sp. nov. and R. vodrazkai sp. nov. Type specimens of three species erroneously assigned to Eleidae are refigured and their true affinities discussed. This study underscores the value of eleozooids in distinguishing between otherwise closely similar eleid species. The Bohemian late Cenomanian-early Turonian eleid fauna is dominated by encrusting species, a pattern that is typical of nearshore localities and contrasts with offshore chalks where erect, vincularian species are more numerous.

show abstract

The Late Cretaceous brittle star Ophiosmilax? alternatus from Europe and northern Africa

Cited by 4 publications

References 3 publications

<p><strong>Observations on Onychaster Meek & Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*</strong></p>

<p><strong>Observations on Onychaster Meek & Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*</strong></p>

The evolutionary relationship between arm vertebrae shape and ecological lifestyle in brittle stars (Echinodermata: Ophiuroidea)

Operculate cyclostome bryozoans (Eleidae) from the Bohemian Cretaceous

Contact Info

Product

Resources

About

The Late Cretaceous brittle star Ophiosmilax? alternatus from Europe and northern Africa

Cited by 4 publications

References 3 publications

<p><strong>Observations on Onychaster Meek &amp; Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*</strong></p>

<p><strong>Observations on Onychaster Meek &amp; Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*</strong></p>

The evolutionary relationship between arm vertebrae shape and ecological lifestyle in brittle stars (Echinodermata: Ophiuroidea)

Operculate cyclostome bryozoans (Eleidae) from the Bohemian Cretaceous

Contact Info

Product

Resources

About

<p><strong>Observations on Onychaster Meek & Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*</strong></p>

<p><strong>Observations on Onychaster Meek & Worthen, 1868 (Ophiuroidea: Onychasteridae) (Famennian – Visean age)*</strong></p>