A broadly resolved molecular phylogeny of New Zealand cheilostome bryozoans as a framework for hypotheses of morphological evolution

Abstract

Larger molecular phylogenies based on ever more genes are becoming commonplace with the advent of cheaper and more streamlined sequencing and bioinformatics pipelines. However, many groups of inconspicuous but no less evolutionarily or ecologically important marine invertebrates are still neglected in the quest for understanding species- and higher-level phylogenetic relationships. Here, we alleviate this issue by presenting the molecular sequences of 165 cheilostome bryozoan species from New Zealand waters. New Zealand is our geographic region of choice as its cheilostome fauna is taxonomically, functionally and ecologically diverse, and better characterized than many other such faunas in the world. Using this most taxonomically broadly-sampled and statistically-supported cheilostome phylogeny comprising 214 species, when including previously published sequences, we tested several existing systematic hypotheses based solely on morphological observations. We find that lower taxonomic level hypotheses (species and genera) are robust while our inferred trees did not reflect current higher-level systematics (family and above), illustrating a general need for the rethinking of current hypotheses. To illustrate the utility of our new phylogeny, we reconstruct the evolutionary history of frontal shields (i.e., a calcified bodywall layer in ascus-bearing cheilostomes) and asked if its presence has any bearing on the diversification rates of cheilostomes.

Paleozoic origins of cheilostome bryozoans and their parental care inferred by a new genome-skimmed phylogeny

“…S1A). In a genus-level example, Steginoporella , represented in the next most recent cheilostome molecular phylogeny by five species ( 20 ), is now represented by nine species: Steginoporella was, and still is, monophyletic. The genus Microporella is here inferred by molecular sequences to include Diporula and Flustramorpha .…”

“…The procedure summarized herein follows ( 20 ) closely with minimum modifications. Colonies whose sequences are presented here were collected and preserved in 70 to 96% ethanol (table S1).…”

“…The topology of the phylogenetic tree in this contribution was compared to that from ( 20 ) to gauge whether a substantial increase in sampled taxa had any detectable bearing on the inferred topology. To this end, we trimmed samples not represented in ( 20 ) from the full tree (fig. S1) and using Dendroscope ( 68 ) compared the topology of their remaining 263 shared taxa using the I cong index ( 69 ).…”

“…Two nuclear rRNA operon genes (18S and 28S) were also identified and annotated using RNAmmer (57). A total of 315 published cheilostome sequences (20,(58)(59)(60) and the mitogenomes and rRNA operons of 31 non-cheilostome out-group taxa, both bryozoan and nonbryozoan, were aligned with our sequences to compile a broader out-group taxon sample (table S3).…”

Apprehending novel biodiversity redux – thirteen new genera and three new families of Zealandian Bryozoa, with the first living species of the Eocene‒Miocene genusVincularia(Vinculariidae)

“…Dennis P. Gordon of Ellisina (Orr et al, 2021). For this reason, Ellisantropora, which lacks the ellisinid character of an ooecial heterozooid, having instead its ooecium formed by the distal autozooid, is provisionally included in Antroporidae.…”