Polyplacophora from the Eocene of Gant, Hungary

Dell’Angelo, Bruno; Sosso, Maurizio; Kroh, Andreas; Dulai, Alfréd

doi:10.3140/bull.geosci.1517

Cited by 3 publications

(1 citation statement)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S8). Our time-calibrated phylogeny indicates shell eyes evolved in the last common ancestor of Acanthopleurinae + Toniciinae between 150 and 100 million years (Ma) ago and in Schizochitonidae between 250 and 200 Ma ago, estimates considerably older than the earliest verified fossil evidence of shell eyes in fossil Toniciinae from the middle Eocene (48 to 38 Ma ago) and fossil Schizochitonidae represented by two species of Incisiochiton from the Lower Paleocene (66 to 59.2 Ma ago) ( 48 – 50 ). Time-calibrated phylogeny and fossil evidence together indicate that both instances of shell eyes in chitons represent the most recent origins of camera-type eyes known.…”

Section: Chitons Rapidly Evolved Visual Systems Four Times In Two Dis...mentioning

confidence: 85%

A morphological basis for path-dependent evolution of visual systems

Varney,

Speiser,

Cannon

et al. 2024

Science

View full text Add to dashboard Cite

Path dependence influences macroevolutionary predictability by constraining potential outcomes after critical evolutionary junctions. Although it has been demonstrated in laboratory experiments, path dependence is difficult to demonstrate in natural systems because of a lack of independent replicates. Here, we show that two types of distributed visual systems recently evolved twice within chitons, demonstrating rapid and path-dependent evolution of a complex trait. The type of visual system that a chiton lineage can evolve is constrained by the number of openings for sensory nerves in its shell plates. Lineages with more openings evolve visual systems with thousands of eyespots, whereas those with fewer openings evolve visual systems with hundreds of shell eyes. These macroevolutionary outcomes shaped by path dependence are both deterministic and stochastic because possibilities are restricted yet not entirely predictable.

show abstract

Section: Chitons Rapidly Evolved Visual Systems Four Times In Two Dis...mentioning

confidence: 85%

A morphological basis for path-dependent evolution of visual systems

Varney,

Speiser,

Cannon

et al. 2024

Science

View full text Add to dashboard Cite

show abstract

Phylogeny, divergence times and species delimitation of Tonicia (Polyplacophora: Chitonidae) from the eastern Pacific Ocean

Ibáñez

Eernisse

Méndez

et al. 2019

Zoological Journal of the Linnean Society

View full text Add to dashboard Cite

The chiton genus Tonicia is composed of 12 species, 11 of which are found in the eastern Pacific, but the taxonomic status and geographical distribution of these species have long been controversial. In this study, we compare eastern Pacific Tonicia species using molecular systematics. The molecular markers cytochrome oxidase c subunit I (COI), 16S and 18S ribosomal RNA were used to estimate the phylogenetic relationships and divergence times among species. Species delimitations were inferred using a Bayesian generalized mixed Yule coalescent (bGMYC) and a Bayesian Poisson tree processes (bPTP) approach. We assigned southeastern Pacific specimens to nine recognized species based on their morphology, but these were resolved into only six species in our molecular phylogeny, suggesting that three of the recognized morpho species need to be synonymized. The bGMYC and bPTP analyses indicate the existence of six total coalescent groups interpreted as seven species in our gene tree results. Likewise, pairwise genetic distances, phylogenetic estimates and coalescent approaches support only seven lineages when considering specimens that match the nine currently recognized southeastern Pacific Tonicia species. We suggest that the colouration and morphological characters used to identify Tonicia species must be re-examined in depth.

show abstract