Yacimiento paleontológico de Taima-Taima. “Una ventana a la última Edad de Hielo en la costa caribeña”

El yacimiento de Taima-Taima, ubicado en la costa caribeña de Venezuela, es un sitio de referencia para el estudio de los primeros pobladores de las Américas. Luego de las primeras excavaciones sistemáticas realizadas en el lugar en la década de 1960, abundantes restos de megafauna y inequívocas evidencias antrópicas fueron encontradas. El ambiente sedimentario ha sido referenciado como un antiguo manantial, y dataciones absolutas le asigan al sitio una edad comprendida entre los 9.650 ± 80 y 14.440 ± 435 años de antigüedad; sustentándose así la teoría de que el paleoindio de la región usó estos bebederos naturales para acechar y cazar grandes mega-mamíferos. Una reseña histórica del yacimiento de Taima-Taima es ofrecida, apuntalando la importancia de carácter patrimonial, histórico y científico del lugar.The Taima-Taima deposit, located on the Caribbean coast of Venezuela, is a reference site for the study of the first settlers of the Americas. After the first systematic excavations carried out on the site in the 1960s, abundant remains of megafauna and unequivocal anthropic evidence were found. The sedimentary environment has been referenced as an ancient spring, and absolute dates give the site an age between 9,650 ± 80 and 14,440 ± 435 years old; thus sustaining the theory that the Paleoindian in the region used these natural drinking troughs to stalk and hunt large mega-mammals. A historical review of the Taima-Taima site is offered, underlining the importance of heritage, historical and scientific character of the place

A fossil assemblage from the mid–late Maastrichtian of Gavdos Island, Greece, provides insights into the pre-extinction pelagic ichthyofaunas of the Tethys

The global body-fossil record of marine ‘fishes’ from the time interval immediately preceding the Cretaceous–Paleogene Extinction is markedly poor. This deficiency appears to be further exacerbated with regards to offshore and deep-water taxa, obscuring our understanding of the state and composition of corresponding vertebrate faunas at the onset of this major extinction event. Recent fieldwork in the mid–late Maastrichtian exposures of the Pindos Unit in Gavdos Island, Greece, yielded a small but informative sample of fossil ‘fishes’, which inhabited the Tethys approximately three to four million years before the extinction. In this work we describe this sample, which comprises between eight and nine discrete morphotypes of various size classes, belonging to †Ichthyodectoidei, Aulopiformes (†Dercetidae, †Enchodontidae, †Ichthyotringidae), cf. †Sardinioididae, as well as the hexanchid shark †Gladioserratus sp. The new material expands the faunal list for the Maastrichtian of Gavdos Island, and the Pindos Unit as a whole, and further allows for the description of a new genus and species of †Enchodontidae and a new species of †Ichthyotringidae. The two new taxa are found to be widespread in the Maastrichtian of the Pindos Unit. The overall character of the assemblage agrees with previous interpretations of an offshore and rather deep depositional environment for the fossiliferous horizons. Furthermore, it exhibits a higher diversity than, and little taxonomic overlap with penecontemporaneous teleost assemblages from the Tethys, and informs on the otherwise poorly known Maastrichtian offshore and deep-water marine ichthyofaunas of the region

New record of Pachyarmatherium (Cingulata: Pachyarmatheriidae) from the Late Pleistocene in Venezuela

The Falcón state, in northwestern Venezuela, preserves one of the oldest localities documenting human presence on the Americas in association with megafauna remains. One of these localities is the Late Pleistocene Taima-Taima site, which is located in the vicinity of the Caribbean coast. Excavations since the 1960s in the Taima-Taima site, and surroundings, have offered new insights into the faunal assemblages that inhabited this arid coastal savannah region during the Late Pleistocene. Isolated osteoderms collected in recent prospections allow us to report here the presence of the extinct cingulate Pachyarmatherium cf. brasiliense and Pachyarmatherium sp. from the Taima-Taima site, and the new locality Cucuruchú (Las Dunas). The record of these taxa in the Late Pleistocene of the Falcón state increases the known paleodiversity of Cingulata for the region and expands the geographical distribution of the genus, which is poorly known in South America

“Muaco” un yacimiento olvidado del pleistoceno tardío de Venezuela

Venezuela presenta un alto potencial paleontológico, evidenciando en los innumerables registros fósiles reportados a lo largo de la geografía nacional, desde principios del siglo XIX. En este artículo se quiere dar continuidad a la divulgación de algunos de los yacimientos paleontológicos más importantes del territorio venezolano. Se trata del sitio Muaco (Pleistoceno Tardío), el cual fue uno de los primeros yacimientos estudiados de manera sistemática en la región durante la mitad del siglo XIX, y considerado durante mucho tiempo, el sitio con presencia de actividad humana más antiguo en el continente. La excavación del sitio estuvo liderizada por el reconocido geólogo y paleontólogo de origen español Dr. José Royo y Gómez que dejó un valioso legado científico y cultural a la ciencia paleontológica de Venezuela y de las Américas.Venezuela has a high paleontological potential. It has been evidenced with the fossil record reported throughout the national geography since the beginning of the 19th century. In this article, we want to give continuity to the disclosure of some of the most important paleontological sites in Venezuelan territory. It is the Muaco site (Late Pleistocene), which was one of the first sites systematically studied in the region during the mid-nineteenth century, and considered for a long time, the site with the oldest human activity on the continent. The excavation of the site was led by the renowned geologist and paleontologist of Spanish origin Dr. Jose Royo y Gomez, who left a valuable scientific and cultural legacy to the paleontological science of Venezuela and the Americas

Fish otoliths from the middle Miocene Pebas Formation of the Peruvian Amazon

A small assemblage of 22 otoliths was identified from the historical collection of Bluntschli and Peyer gathered in 1912 on the Itaya riverbank at Iquitos, Peru (Amazonia), from the Pebas Formation. The Pebas Mega-Wetland System in western Amazonia during the Miocene represented a unique, albeit short-lived, biotope characterized by a pronounced endemic evolution with gigantism in some vertebrate groups (e.g., turtles, crocodylians). Thus far, fishes have mainly been recorded based on isolated skeletal remains and teeth. Here, we describe the first well-preserved otolith assemblage from the Pebas Formation. This otolith assemblage adds a new facet to the fauna by complementing the skeletal bony fish data, primarily with species of the Sciaenidae and, to a lesser extent, Ariidae and Cichlidae. The sciaenids and ariids indicate that migration must have occurred between the marginal marine environments to the north and the Pebas Wetland System. The otoliths also indicate the likelihood of endemic developments of adapted marine immigrants to the Pebas Wetland System, some of which have become extinct (Pogonias, Umbrina), while others now represent typical South American freshwater fish groups (Plagioscion). Six new species are described based on otoliths, one in the Cichlidae—Cichlasoma bluntschlii n. sp., one in the Ariidae—Cantarius ohei n. sp., and four in the Sciaenidae—Pebasciaena amazoniensis n. gen. et n. sp., Plagioscion peyeri n. sp., Pogonias tetragonus n. sp. and Umbrina pachaula n. sp

Shark and ray diversity in the Tropical America (Neotropics)—an examination of environmental and historical factors affecting diversity

We present the first comprehensive review of the present and past shark and ray diversity in marine waters of Tropical America, examining the patterns of distribution in the Eastern Central Pacific (EP) and Western Central Atlantic (WA) realms. We identified the major regions of diversity and of endemism, and explored the relations to physical variables. We found a strong relationship between shark and ray diversity with area and coastal length of each province. The Tropical Northwestern Atlantic Province is characterized by high diversity and greater occurrence of endemic species, suggesting this province as the hotspot of sharks and rays in Tropical America. The historical background for the current biogeography is explored and analyzed. Referential data from 67 geological units in 17 countries, from both shallow and deep-water habitats, across five time-clusters from the Miocene to the Pleistocene were studied. New data include 20 new assemblages from six countries. The most diverse Neogene and extant groups of shark and ray are Carcharhiniformes and Myliobatiformes, respectively. The differentiation between Pacific and Atlantic faunas goes to at least the middle Miocene, probably related with the increasing closure of the Central American Seaway acting as a barrier. The highest faunal similarity between the assemblages from the EP and the WA at the early Miocene could be related to the lack of a barrier back then, but increased sampling is needed to substantiate this hypothesis

Pliocene sigmodontine rodents (Mammalia: Cricetidae) in northernmost South America: test of biogeographic hypotheses and revised evolutionary scenarios

We document the first occurrence of Sigmodontinae (Mammalia, Rodentia, Cricetidae) from the Pliocene of northern South America, from the San Gregorio Formation of northwestern Venezuela. The recovered isolated molars are identified as Oligoryzomys sp. and Zygodontomys sp., two currently widespread sigmodontines in South America. These records constitute the oldest representatives of these genera, potentially new species, and the first Pliocene occurrence for Oryzomyini and the whole subfamily outside Argentina. Hypotheses on the historical biogeography of sigmodontines have been constructed almost exclusively using genetic data and the fossils we report provide a new kind of evidence. The occurrence of Oligoryzomys sp. and Zygodontomys sp. in Venezuela provides novel information for the diversification models suggested for Oligoryzomys, by supporting a potential eastern corridor of open environments from northern to southern South America. The presence of sigmodontines from the locality home of the new reports, Norte Casa Chiguaje, is consistent with the palaeoenvironmental conditions originally proposed for it based on mammals and botanical records, being characterized as mixed open grassland/forest areas surrounding permanent freshwater systems. The new sigmodontine evidence is used to discuss the putative scenarios of the ancient evolution of the subfamily in South America, favouring a model in which open areas (savannahs) to the east of the Andes played crucial role aiding or obstructing Late Miocene-Pliocene sigmodontine dispersion southwards

First fossil record (Middle Miocene) of the viper shark Trigonognathus Mochizuki and Ohe, 1990, in the Mediterranean realm

The genus Trigonognathus Mochizuki and Ohe, 1990, is a monospecific taxon of `lantern sharks¿ (i.e., family Etmopteridae), a group of small-sized bioluminescent deep-sea chondrichthyans, ranging in mature male specimens between 42¿47 cm total length, and at least 52 cm for females (Ebert et al., 2021). This shark inhabits the upper continental slopes as well as the uppermost slope of seamounts, often at the bottom, at depths ranging between 250¿1000 m, but has been caught at 150 m and 270 m in deep open waters (Mochizuki and Ohe, 1990; Compagno et al., 2005; Ebert et al., 2021). Only two species have been described thus far, the extant species Trigonognathus kabeyai Mochizuki and Ohe, 1990, and the extinct ¿Trigonognathus virginiae from the middle Eocene of France (Cappetta and Adnet, 2001). Trigonognathus kabeyai exhibits a combination of morphological characteristics that are unique among Squaliformes, like a highly protrudable jaw articulation (Shirai and Okamura, 1992; Straube et al., 2010), and a lack of dignathic heterodonty. Additionally, the tearing-type dentition, and strong monognathic heterodonty with hypertrophied anterior teeth, differentiate it from the genus Squalus and Cirrigaleus (with cutting-type dentition), and Centroscyllium and Aculeola (with no monognathic heterodonty and clutching-type dentition) (Cappetta and Adnet, 2001). The geographic distribution of T. kabeyai is restricted to the Pacific Ocean, in the Wakayama and Tokushima coasts of Japan (Mochizuki and Ohe, 1990; Shirai and Okamura, 1992; Ebert et al., 2021), Taiwan (Ebert et al., 2013), and in the north-west of Hawaii (Wetherbee and Kajiura, 2000). However, the fossil record of the genus Trigonognathus indicates a broader geographic distribution in the past (Aguilera and Rodriguez de Aguilera, 2001; Cappetta and Adnet, 2001; Carrillo-Briceño et al., 2015). These findings include ¿T. virginiae from the middle Eocene of Landes (eastern Atlantic), southwestern France (Cappetta and Adnet, 2001), and two isolated teeth assigned to Trigonognathus sp. and Trigonognathus aff. kabeyai from the Upper Miocene of Panama (Carrillo-Briceño et al., 2015) and the Upper Miocene¿Lower Pliocene of Venezuela (Caribbean Sea) (Aguilera and Rodriguez de Aguilera, 2001), respectively. Given the apparent rarity of this elusive taxon, any new finding, especially in the fossil record, is of note and increases our knowledge of this genus. Herein we describe a Middle Miocene locality with the first known record of Trigonognathus in the Mediterranean realm (south-eastern Spain), which offers new insight into the paleoenvironmental and paleobiogeographic history of this shark. In addition, with the objective of providing new information about possible diagnostic characteristics of the genus, the first description of its internal tooth histology is provided