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From the oldest Cretaceous marine sediments of Jamaica, the Copper Limestone within the Devils Racecourse Formation (Benbow Inlier, Clarendon Block), the oldest known coral fauna of the Caribbean is described. The small but diverse fauna encompasses 18 species in 17 genera of the suborders Amphiastraeina, Archeocaeniina, Heterocoeniina, Faviina, Fungiina, Microsolenina, and Stylinina. The fauna contains the first representatives of the suborder Amphiastraeina in the Caribbean and the Americas. One genus of the family Amphiastreidae, Monoaulastrea, and three species— Monoaulastrea rawi, Latusastrea rubrolineata, Camptodocis corralesi—are described as new. The preoccupied coral genus Floria is replaced by the new name Floriastrea. The new fauna shows relationships to faunas from the late Berriasian to late Albian. Most species are shared with the Hauterivian faunas from Georgia in the central Tethys and the Paris Basin in the Boreal, but also with younger faunas such as the Barremian of Central Mexico, the early Aptian of Greece and the early Albian of the Bisbee Basin (Northern Mexico).
Apektocrinus ubaghsi new genus and species is a monospecific taxon assigned to the new family Apektocrinidae based on additional preparation of a single previously studied specimen. Apektocrinus is among the oldest known crinoids (Early Tremadoc, Early Ordovician). Although expressing crinoid apomorphies, it is interpreted as retaining plesiomorphies in its arms reflecting early edrioasteroid rather than blastozoan (eocrinoid) ancestry. Apomorphies represent basal crinoid and cladid (crownward) levels of phylogeny.
Restudy fortifies previous reports of the presence of a basal echinoderm plesiomorphy; floor plates above brachials in the arms of Apektocrinus, as well as in other approximately contemporary crinoids. Apektocrinus furnishes the first record of podial basins in crinoid arms. Arms and calyx of Apektocrinus merge gradually, facilitated by continuations of interbrachials (extraxial body plates) extending onto the arms and separating floor plates from brachials. These arm interbrachials, which diminish and pinch out distally as floor plates nestle into the brachial (adoral) groove, have not been recognized as such in crinoids.
Morphometric analyses of shell morphology in the Cretaceous nautiloid Eutrephoceras clementinum (d'Orbigny, 1840) (Cephalopoda, Mollusca) from the Ariyalur area, southern India, reveal ontogenetic change from hatching to maturity as well as intra-specific variation in shell morphology. The shell breadth has a negative allometric relationship with shell diameter and with whorl height, and the umbilicus diameter has a positive allometric relationship with shell diameter. This shows that shell shape became relatively thinner with less variation, and the umbilicus diameter became relatively broader with growth. The siphuncle position moves from a dorso-central to ventro-central position with growth. A constriction was recognized on the early whorl at 20 mm in shell diameter, and the interval angles of succeeding septa were changed at the 8th septum, indicating that they hatched at this stage. The bending of umbilical walls of apertures toward the center of coiling suggests that E. clementinum attained maturity at about 115 mm in shell diameter. The comparison of the shell morphology of E. clementinum with that of E. bouchardianum (d'Orbigny, 1840) reported in the literature clarifies their difference in whorl shape and umbilical size, especially in the adult stage. This kind of morphometric study of nautiloids is essential for elucidating their adaptive designs for environment and mode of life, functional shell morphology, taxonomy, phylogeny, and evolution.
The occurrence of freshwater turtle remains in the late Miocene lignites of southern Tuscany (Montebamboli and Casteani, Italy) has been known since the nineteenth century. Three chelonian species were recognized by Ristori in 1891: Emys depressa, E. campanii, and E. parva. Revision of their type material, together with the study of new fossils from a different but correlated locality, Pian Calcinaio (Scansano), allows one to state that they can be referred to the genus Mauremys and that they belong to one single species. The new combination M. campanii (Ristori, 1891) is here proposed. Phylogenetic analysis indicates that M. campanii is closely related to the modern post-Miocene group of Mauremys species and shows a sister-group relationship with the Plio-Pleistocene M. gaudryi. The remains of M. campanii come from an insular setting which progressively lost its endemic mammal fauna, defined as the Oreopithecus Zone Fauna, enabling us to compare the pattern of survival of the chelonians with that of the mammals. In contrast to the radical turnover suffered by mammals, softshell turtles (Trionyx sp.) and terrapins (M. campanii) are present both in the pre-Messinian V1–V2 and Messinian V3 assemblages. Terrestrial tortoises (Testudo amiatae Pantanelli, 1893, Testudo s.l.) show a different pattern, because they appear only in the V3 assemblage, possibly because they apparently dispersed into Italy as recently as the Messinian. M. campanii represents the southernmost evidence of the genus Mauremys in the uppermost Miocene of Europe, filling a gap in the palaeogeographic and chronological distribution of this genus.
The Callovian Lagerstätte of La Voulte-sur-Rhône represents deep (bathyal) environments at the bottom of a submarine rocky slope. Three sea star body fossils partially replaced with pyrite were collected from clay beds. A small, stellate specimen is assigned to Terminaster cancriformis, a species already known from Jurassic clay deposits of Germany, Switzerland and England. The morphology of Terminaster illustrates mostly plesiomorphic features for post-Paleozoic sea stars, and the genus may be considered either as a paedomorphic Zoroasteridae or a stem group Forcipulatacea. Two specimens of a large multiarmed sea star are assigned to Decacuminaster n. gen. solaris n. sp., characterized by a lack of abactinal plates and an axial skeleton typical of the Velatida. The two genera Xandarodaster and Plesiastropecten are close to Decacuminaster and must be transferred to the Velatida. In modern oceans, the association of a multiarmed Velatida and a zoroasterid-like species would be typical of bathyal/abyssal environments, which suggests that these groups explored deep sea environments early in their history.
Seven previously unrecognized fusulinid species from Lower Permian (Wolfcampian and Leonardian) turbidites near Conglomerate Mesa in east-central California, four of which are named as new species, are here described and figured. The four new species are Schwagerina merriami, S. wildei, Parafusulina mackevetti, and Skinnerella rossi. These fusulinid species have close affinities to similar taxa in Texas and northeastern Nevada, and they are distinct from some other faunas of slightly different age in the Conglomerate Mesa area that are dominated by endemic species and other species with Eastern Klamath Mountains affinities.
Ten newly recovered Dunbarites specimens significantly extend the known stratigraphic range of Dunbarites. These include the first documented Midcontinent Basin records of the Missourian type species Dunbarites rectilateralis (Miller, 1930) from north-central Oklahoma. Additional species of Dunbarites from south-central Oklahoma and north-central and West Texas are described as Dunbarites wewokensis n. sp. and Dunbarites boardmani n. sp. Although Dunbarites is an extremely rare component (∼0.025 percent) of Middle and Upper Pennsylvanian ammonoid assemblages, Ruzhencev and Bogoslovskaya (1971, 1978) suggested that Dunbarites and ParashumarditesRuzhencev, 1939 be used as genozone markers for the Kasimovian [Zhigulevian] Stage (Missourian in North America). As demonstrated by this report, the range of Dunbarites is not confined to the Kasimovian, thereby precluding its use as a Kasimovian Stage indicator.
Here we report the first detailed reconstruction of the eye and visual system of a Paleozoic ostracod, namely the dimorphic primitiopsid (Palaeocopa) Primitiopsis planifronsJones, 1887. Evidence from the cuticular lens morphology and its position on the valve suggests that P. planifrons had a naupliar eye, which is the most common optical system in crustaceans. The characters of the eye, such as the separated cuticular lens on each valve and the strongly calcified nature of the lens and its diameter, are concordant with that of some Recent podocopid ostracods in which a divided type of naupliar eye is present. Ray tracing of the reconstructed cuticular lens of the primitiopsid species demonstrates strong spherical aberration and a very long focal length (as in the eye of podocopids), which implies the presence of a spherical mirror (tapetum) below the lens. Study of the ontogenetic change of the valve thickness aids the suggestion that P. planifrons was nektobenthic. The size of its cuticular lens in relation to that of living podocopid ostracods, and the water depth at which these Recent forms occur, indicates that P. planifrons may have lived in a relatively shallow, well lit environment such as the deep subtidal zone. These interpretations are consistent with supposed paleoenvironmental conditions derived from geological evidence. Thus, analysis of the nature and relative size of the eye gives an independent test to help identify paleoenvironmental parameters of long extinct ostracods.
Deltaplax new genus, Deltaplax burdicki new species, and Deltaplax dellangeloi new species (Mollusca, Polyplacophora, Neoloricata, Multiplacophora) from the Mississippian Lower Buffalo Wallow Group (Chesterian) of Indiana, USA are described. The new genus is established by one partially articulated and one associated specimen with marginal fringes of two types of large spines, bilaterally symmetrical head and tail valves, and fifteen medial valves arranged in three longitudinal columns similar to those described previously for other multiplacophorans. The two specimens represent separate species differentiated by morphologies of the auxiliary valves, one type of spine, and subtrapezoidal versus triangular tail valves. The tail valve of the articulated specimen also had sutural laminae that projected under the preceding intermediate valve. The presence of sutural laminae allows for placement of multiplacophorans in Subclass Neoloricata of Class Polyplacophora. The head, intermediate, and tail valves are mucronate with comarginal growth lines and ridged insertion plates that probably inserted into soft tissue comparable to the girdle of modern polyplacophorans. The new specimens also indicate one left-handed, one auxiliary, and one right-handed valve in multiplacophorans was equivalent to a single bilaterally-symmetrical intermediate valve of extant polyplacophorans. However, multiplacophoran head valves have plates that project from the lower layer at the lateral margins and articulate with the first intermediate valves that overlap the head and second intermediate valves. These features have not been observed in more typical neoloricates, fossil or modern. Pending systematic revision of the class, Multiplacophora thus is retained as a separate order distinguished by the unique shared characters.
We document evidence of endophytic oviposition on fossil compression/impression leaves from the early Eocene Laguna del Hunco and middle Eocene Río Pichileufú floras of Patagonia, Argentina. Based on distinctive morphologies and damage patterns of elongate, ovoid, lens-, or teardrop-shaped scars in the leaves, we assign this insect damage to the ichnogenus Paleoovoidus, consisting of an existing ichnospecies, P. rectus, and two new ichnospecies, P. arcuatum and P. bifurcatus. In P. rectus, the scars are characteristically arranged in linear rows along the midvein; in P. bifurcatus, scars are distributed in double rows along the midvein and parallel to secondary veins; and in P. arcuatum, scars are deployed in rectilinear and arcuate rows. In some cases, the narrow, angulate end of individual scars bear a darkened region encompassing a circular hole or similar feature indicating ovipositor tissue penetration. A comparison to the structure and surface pattern of modern ovipositional damage on dicotyledonous leaves suggests considerable similarity to certain zygopteran Odonata. Specifically, members of the Lestidae probably produced P. rectus and P. bifurcatus, whereas species of Coenagrionidae were responsible for P. arcuatum. Both Patagonian localities represent an elevated diversity of potential fern, gymnosperm, and especially angiosperm hosts, the targets of all observed oviposition. However, we did not detect targeting of particular plant families. Our results indicate behavioral stasis for the three ovipositional patterns for at least 50 million years. Nevertheless, synonymy of these oviposition patterns with mid-Mesozoic ichnospecies indicates older origins for these distinctive modes of oviposition.
Based on the type material and a new, virtually intact skull from the mid-Maastrichtian part (probably Tierra Loma Shale) of the Moreno Formation, San Joaquin Valley, central California, the cranial osteology of the enigmatic mosasaurine Plesiotylosaurus crassidens (Squamata, Mosasauridae) is here described in detail. Plesiotylosaurus is characterized by a protruding rostrum on the snout and mandibles, a wide and virtually unconstricted internarial bar, large and robust pterygoid teeth, and quadrates with distally fused suprastapedial and infrastapedial processes. Distinctly obtruding predental prows, along with a number of elaborate cranial features, suggest a morphological convergence with tylosaurine mosasaurs.
New Palatobaena material from the Hell Creek Formation (Maastrichtian), including the first skull and shell association, from southwestern North Dakota represents a new species named herein Palatobaena cohen. The material consists of 4 skulls, 2 lower jaws, and 2 shells and represents a true biological population (spatially and temporally restricted), which provides unprecedented access to ontogenetic and other intraspecific variation found in this taxon. The skull's round shape and lack of a lingual ridge on the greatly expanded triturating surface indicate its Palatobaena affinities, but it differs from both previously existing Palatobaena taxa in a number of features. The addition of shell characters to the most inclusive baenid phylogenetic analyses (Maximum parsimony and Bayesian) to date indicate that Pa. cohen is sister taxon to the other Palatobaena taxa. Notably, both the maximum parsimony analysis and Bayesian analysis provide strong support for Plesiobaena antiqua as sister to the Palatobaena clade. In addition, both analyses provide strong support for Stygiochelys estesi as sister to the Eocene clade of Baena arenosa and Chisternon undatum, which significantly reduces this clades' ghost lineage. The baenid topology reveals a demonstrably homoplastic trend towards the reduction of the temporal emargination and unique thickening of the posterior portion of the parietals that corresponds with the K/T boundary and is hypothesized to have provided limited protection from increasingly effective mammalian predators.
The Hapsidopareiontidae are microsaurian amphibians known only from the Lower Permian of the U.S. The hapsidopareiontid skull has a large temporal embayment that occupies most of the area of the cheek, in which the quadratojugal is either absent (Hapsidopareion) or present and greatly reduced (Llistrofus). The unique holotype skull of Llistrofus pricei is well preserved in soft clay. It was originally prepared and described in dorsal view only, but has now been prepared completely free of the matrix. This permitted the first description of the palate, occiput and mandible along with a redescription of the rest of the skull, resulting in substantial emendation of previously published descriptions. Comparison with the eight known complete and partial skulls of Hapsidopareion lepton demonstrates that the two genera are much more similar than had been recognized earlier. Their continued separation is advocated, however, based on size difference, a small number of osteological differences, and the difficulty of obtaining comparably detailed morphological information for Hapsidopareion, which is less well preserved than the Llistrofus specimen. The new morphological information, combined with results of recently published cladistic analyses, suggests that Hapsidopareion and Llistrofus are the only microsaurs that can at present be assigned to the Hapsidopareiontidae. The large temporal embayment of hapsidopareiontids might be thought to have significant functional implications, possibly including “escape” of jaw adductor musculature onto the skull roof. Detailed consideration of this possibility reveals morphological evidence to the contrary, however, and the functional implications of the embayment remain uncertain.
The systematic position of taxa from the work of Gerard Troost has been confused and many have not been properly credited. Complete synonymy listings of Troost names indicate that the author and date of many names need revision, including several taxa that can finally be credited to Troost.
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