Diversification dynamics of cheilostome bryozoans based on a Bayesian analysis of the fossil record

Abstract

Cheilostomata is the most diverse and ecologically dominant order of bryozoans living today. We apply a Bayesian framework to estimate macroevolutionary rates of cheilostomes since the Late Jurassic across four datasets: (I) manually curated genus ranges; (II) published text-mined genus ranges; (III) non-revised Paleobiology Database (PBDB) records; (IV) revised and augmented PBDB records. All datasets revealed increased origination rates in the Albian, and a twin K-Pg and Danian extinction rate peak. High origination rates in the Late Selandian-Ypresian in Dataset I indicate the onset of an ascophoran-grade radiation. Lineage-through-time plots confirm the macroevolutionary lag preceding the radiation of cheilostomes in the middle Cretaceous, and their renewed diversification in the late Paleocene and Eocene. A multivariate birth-death model indicates that origination rates are shaped by diversity-dependent dynamics coupled with a positive correlation with sea surface temperature, while extinction rates negatively correlate with sea level. Text-mined data provide broadly similar rate dynamics as manually curated data, although discrepancies could be attributed to the omission of key literature in Dataset II, and the inclusion of new published and unpublished data, and revised ranges in Dataset I. Revision and augmentation of PBDB occurrences were necessary to generate rate profiles akin to those of Datasets I and II and highlight the risks of using unedited occurrence data. Our results support the widely held assumption that diversification dynamics are controlled by both biotic and abiotic factors, and pave the way for integrating fossils with molecular phylogenies to study these processes in more detail.

Lunulite bryozoan biogeography – a convergent global success with a distinct Western Australian twist

“…Fig. 3) mirroring well-established declines in diversity in all bryozoan groups (e.g., Håkansson & Thomsen, 1979McKinney & Taylor, 2001;Stilwell & Håkansson, 2012;Moharrek et al, 2022) and other marine groups. In Europe, the last Danian remnants of the Chalk Sea province were home to only a few, rare species (Berthelsen 1962;Kvachko 1995), while Selandian and Thanetian free-living bryozoans are even more scarce, with four Thanetian taxa reported from Deep Sea Drilling Project site 117 at Rockall Bank (Cheetham & Håkansson, 1972) constituting a post-Danian Paleocene 'hotspot'.…”

Global diversity dynamics in the fossil record are regionally heterogeneous

“…This produces high computational burden, and models for larger sampling regions could not be estimated efficiently. PyRate can alternatively use an efficient Gibbs algorithm to sample from the posterior distribution of the parameters, producing preservation-corrected estimates of origination and extinction times that are virtually identical to those from the Metropolis Hastings algorithm, but with a coarse birth-death model that involves a dramatic loss of resolution in the resulting rate curves 83 . A second programme, LiteRate, has been developed to permit origination and extinction rate estimation for taxonomically large datasets 24 , 25 , gaining computational efficiency by implementing the same birth-death model used by PyRate with the rjMCMC and Metropolis Hastings algorithm, but without estimation of the complex preservation model.…”

Multiple evolutionary transitions of reproductive strategies in a phylum of aquatic colonial invertebrates

“…It was also suggested that endotrophic larvae could be advantageous at greater ocean depths where algal planktonic food is scarce [5]. One argument in favour of these hypotheses is that zygote-spawning malacostegans were (and still are) much less diverse and mostly occupy shallower habitats, while brooding neocheilostomes, which underwent a substantial radiation starting in the late Albian/ early Cenomanian [15,[19][20][21], still make up the vast majority of cheilostomes for all substrates and depths today.…”

“…By contrast, the more advanced neocheilostomes, all of which incubate their offspring and produce short-lived, non-feeding (=endotrophic, i.e. lecithotrophic or placentotrophic) larvae [5,[16][17][18], underwent a substantial radiation starting in the late Albian/early Cenomanian [15,[19][20][21] and make up the vast majority of extant cheilostomes. Although suborder Neocheilostomina d 'Hondt, 1985 [22] is not a currently accepted taxon name, 'neocheilostome' is a utilitarian term that will be used herein to refer to any cheilostome with an ovicell-a calcified brood chamber first found in the calloporid genus Wilbertopora from the late Albian [23].…”