Search for: All records

Sixty-five species and nine indeterminate taxa of Florida Paleogene echinoids are discussed, and their geographic and stratigraphic distributions provided. These include 49 species documented from the Eocene and 16 from the Oligocene. Ten new species are described: Prionocidaris robertsi n. sp., Rhyncholampas mariannaensis n. sp., Rhyncholampas bao n. sp., Weisbordella inglisensis n. sp., Weisbordella libum n. sp., Durhamella tetrapora n. sp., and Brissus jonesi n. sp. from the Eocene; and Plagiobrissus cassadyi n. sp., Eupatagus dumonti n. sp., and Schizaster carlsoni n. sp. from the Oligocene. We reconsidered subjective junior synonyms of all species and resurrect Neolaganum archerensis, Echinocyamus macneili, and Eupatagus mooreanus. Furthermore, we updated the taxonomy for all included species and their known distributions and provide emended diagnoses for the genera and species of Florida Neolaganidae. In addition, we herein report the occurrence of Porpitella micra in Cretaceous strata of the subsurface of Florida. This remarkable finding makes P. micra the earliest known of all the scutelloids. Echinoids within the Ocala Limestone are placed in five echinoid biozones, which are defined within, these include the Oligopygus phelani, Oligopygus haldemani, Oligopygus wetherbyi, Wythella eldridgei, and Haimea brooksi Zones. This document complements the Neogene (including the Quaternary) fossil echinoid fauna of Florida we published in 2020 and represents a compilation of the known Florida Paleogene echinoid record. The region is currently known to have the most speciose and diverse assemblage of Paleogene echinoids in the United States. 

The Brissidae is a family of heart urchins that includes shallow‑water, infaunal species, some of which are rarely observed. One species,Rhynobrissus cuneusCooke, 1957, has only been recorded from the western Atlantic off the coast of North Carolina, USA and in the Gulf of Mexico off the coast of Veracruz, Mexico. This work identifies new records from the coast of Florida, USA, increasing our knowledge of this species’ geographic distribution. 

The echinoid genus Tetrapygus was initially described by L. Agassiz (1841) based on a single species, Tetrapygus niger Molina, 1782. Since the extensive work conducted by Mortensen (1935), Tetrapygus has received limited taxonomic attention over the past century. Recent discoveries of new fossil species of Arbacia Gray, 1835 from the upper Pliocene of northern Chile revealed striking morphological similarities between the two distinct Arbaciidae genera Arbacia and Tetrapygus. These findings compelled new investigations to evaluate the taxonomic status of these genera. Based on molecular mitochondrial (COI), nuclear (28S), and morphological evidence, Tetrapygus niger is here recovered as the sister species to Arbacia dufresnii, both species forming a clade within the phylogeny of South American species of Arbacia. Consequently, the diagnosis and description of Tetrapygus niger are here revised, and the species is reattributed to Arbacia, as previously proposed by A. Agassiz in Agassiz & Desor (1846) under the species name Arbacia nigra. An emended diagnosis of Arbacia is also proposed in light of these new findings.  

The methane seeps on the Pacific margin of Costa Rica support extensive animal diversity and offer insights into deep-sea biogeography. During five expeditions between 2009 and 2019, we conducted intensive faunal sampling via 63 submersible dives to 11 localities at depths of 300–3600 m. Based on these expeditions and published literature, we compiled voucher specimens, images, and 274 newly published DNA sequences to present a taxonomic inventory of macrofaunal and megafaunal diversity with a focus on invertebrates. In total 488 morphospecies were identified, representing the highest number of distinct morphospecies published from a single seep or vent region to date. Of these, 131 are described species, at least 58 are undescribed species, and the remainder include some degree of taxonomic uncertainty, likely representing additional undescribed species. Of the described species, 38 are known only from the Costa Rica seeps and their vicinity. Fifteen range extensions are also reported for species known from Mexico, the Galápagos seamounts, Chile, and the western Pacific; as well as 16 new depth records and three new seep records for species known to occur at vents or organic falls. No single evolutionary narrative explains the patterns of biodiversity at these seeps, as even morphologically indistinguishable species can show different biogeographic affinities, biogeographic ranges, or depth ranges. The value of careful molecular taxonomy and comprehensive specimen-based regional inventories is emphasized for biodiversity research and monitoring. 

Abstract Evidence from the earliest-known crinoids (Tremadocian, Early Ordovician), called protocrinoids, is used to hypothesize initial steps by which elements of the calyx evolved. Protocrinoid calyces are composed of extraxial primary and surrounding secondary plates (both of which have epispires along their sutures) that are unlike those of more crownward fossil and extant crinoids in which equivalent calycinal plating is strongly organized. These reductions inspired several schemes by which to name the plates in these calyces. However, the primary-secondary systems seen in protocrinoids first appeared among Cambrian stem radial echinoderms, with primaries representing centers around which secondaries were sequentially added during ontogeny. Therefore, the protocrinoid calyx represents an intermediate condition between earliest echinoderms and crownward crinoids. Position and ontogeny indicate certain primaries remained as loss of secondaries occurred, resulting in abutting of primaries into the conjoined alternating circlets characteristic of crinoids. This transformative event included suppression of secondary plating and modification or, more commonly, elimination of respiratory structures. These data indicate subradial calyx plate terminology does not correspond with most common usage, but rather, supports an alternative redefinition of these traditional expressions. Extension and adoral growth of fixed rays during calyx ontogeny preceded conjoined primaries in earliest crinoids. Restriction with modification or elimination of calyx respiratory structures also accompanied this modification. Phylogenetic analyses strongly support crinoid origination from early pentaradiate echinoderms, separate from blastozoans. Accordingly, all Tremadocian crinoids express a distinctive aggregate of plesiomorphic and apomorphic commonalities; all branch early within the crinoid clade, separate from traditional subclass-level clades. Nevertheless, each taxon within this assemblage expresses at least one diagnostic apomorphy of camerate, cladid, or disparid clades. 

A new species of clypeasterid sea biscuit, Clypeaster brigitteae n. sp., is described from material collected in the Philippines at depths between 100 and 200 m. The new taxon increases the number of Clypeaster species recorded from the Philippines to nine, representing nearly a quarter of the world’s diversity of the genus. Other Philippine species include: C. annandalei Koehler, 1922; C. fervens Koehler, 1922; C. humilis (Leske, 1778); C. japonicus Döderlein, 1885; C. latissimus (Lamarck, 1816); C. pateriformis Mortensen, 1948; C. reticulatus (Linnaeus, 1758); and C. virescens Döderlein, 1885. Using type material where available, each of these species is compared and contrasted with C. brigitteae n. sp. in tables consisting of new data derived from general test shape and size, petal structure, food grooves, plate architecture, internal structure, and morphology of spines, pedicellariae, and tube feet. 

Echinoids are key components of modern marine ecosystems. Despite a remarkable fossil record, the emergence of their crown group is documented by few specimens of unclear affinities, rendering their early history uncertain. The origin of sand dollars, one of its most distinctive clades, is also unclear due to an unstable phylogenetic context. We employ 18 novel genomes and transcriptomes to build a phylogenomic dataset with a near-complete sampling of major lineages. With it, we revise the phylogeny and divergence times of echinoids, and place their history within the broader context of echinoderm evolution. We also introduce the concept of a chronospace – a multidimensional representation of node ages – and use it to explore methodological decisions involved in time calibrating phylogenies. We find the choice of clock model to have the strongest impact on divergence times, while the use of site-heterogeneous models and alternative node prior distributions show minimal effects. The choice of loci has an intermediate impact, affecting mostly deep Paleozoic nodes, for which clock-like genes recover dates more congruent with fossil evidence. Our results reveal that crown group echinoids originated in the Permian and diversified rapidly in the Triassic, despite the relative lack of fossil evidence for this early diversification. We also clarify the relationships between sand dollars and their close relatives and confidently date their origins to the Cretaceous, implying ghost ranges spanning approximately 50 million years, a remarkable discrepancy with their rich fossil record.