Extant Specimens Research Articles

Inner structural organization of the mandibular corpus in the late Early Pleistocene human specimens Tighenif 1 and Tighenif 2

The present study investigates the inner structural organization of the two mandible specimens Tighenif 1 and Tighenif 2 from the late early Pleistocene site of Tighenif, Algeria. Using (micro)tomographic scans, we built a new protocol to investigate the cortical bone topography at the post-canine level. We selected two cross-sectional slices placed between the P3/P4 and M1/M2 on the right and left sides and assessed the cortical bone thickness topography (CBT) on each slice. Our analyses demonstrate that the mandibles from Tighenif exhibit higher CBT and a different topographic distribution pattern at the molar level than in modern humans, resulting in a proportionally more robust inner structure, while a similar signal is observed between the fossil and extant specimens at the premolar level. Further studies need to be done in order to determine if this feature is related to functional constraints during mastication or paramasticatory activities; or if it is related to any independent evolutionary process.

Occurrence of Dryobalanops Gaertn. (Dipterocarpaceae) in the late Miocene of Bengal basin, India and biogeography of the genus during the Cenozoic of Southeast Asia

ABSTRACTWe report here the occurrence of petrified wood resembling the modern dipterocarp Dryobalanops from the Neogene (late Miocene) of the Bengal Basin, India. We have determined the taxonomic position by comparing its anatomical features with similar extant and fossil specimens and have finally identified this late Miocene wood as Dryobalanoxylon neosumatrense. The record of this new member of Dipterocarpaceae indicates that it was present in a tropical, warm and humid eastern India during the late Miocene. Considering all earlier fossil records of Dryobalanops we suggest that this taxon was a common forest element in Asia during Neogene-Quaternary time. We also review in detail the biogeographic history of this taxon and suggest a possible migration route.

The golden age of arthropods: ancient mechanisms of colour production in body scales.

Insect colour is extremely diverse and produced by a large number of pigmentary and nanostructural mechanisms. Considerable research has been dedicated to these optical mechanisms, with most of it focused on chromatic colours, such as blues and greens, and less on achromatic colours like white and gold. Moreover, studies on the evolution of these colours are less common and largely limited to inferences from extant organisms, in part because of the limited amount and types of available fossil material. Here, we directly compare nanostructure and colour of extant and amber-preserved (approx. 15 and 99 Myr old, respectively) gold-coloured representatives of micromoths (Lepidoptera: Micropterigidae) and springtails (Collembola: Tomoceridae). Using electron microscopy, microspectrophotometry and finite domain time difference optical modelling, we show that golden coloration in the extant micromoth is produced by nanometre-scale crossribs that function as zero-order diffraction gratings and in the springtail by a diffraction grating without crossribs. Surprisingly, nanostructure and thus predicted colour of the amber-preserved specimens were nearly identical to those of their extant counterparts. Removal of amber enabled direct colour measurement of the fossil micromoth and further revealed that its colour matched both that of the extant specimen and the predicted colour, providing further support for our optical models. Our data thus clearly show an early origin and striking conservation of scale nanostructures and golden coloration, suggesting strong selection pressure either on the colour itself or on the mechanisms that produce the colour. Furthermore, we show the thus-far untapped potential for the use of amber-preserved specimens in studies on the evolution of organismal coloration.

Challenges of Establishing Native versus Exotic Status of Herbarium Specimens

In cases where invasive species are presumed to be strictly exotic, the discovery that the species is also native can be disconcerting for researchers and land managers responsible for eradicating an exotic invasive. Such is the case with reed canarygrass (Phalaris arundinacea), for which decades of misinformation led to the call for nationwide control of this species in the United States. However, native populations were first reported by LaVoie and then later confirmed by Casler with molecular analyses. This, coupled with the discovery by Anderson that this species has been used in weavings by Native Americans for centuries, also made the native forms of interest for protection. Identifying the native status of historic, herbarium specimens via molecular analyses is of great interest to determine localities of native populations for confirmation with extant specimens. Genetic-based methods describing DNA polymorphism of reed canary grass are not well developed. The goal of the presented research is to assess the utility of genomic DNA obtained from historic (herbaria) and extant (fresh) tissue of reed canarygrass and the application of using Diversity Arrays Technology sequencing low density for genetic population studies.

<p><strong>First fossil record of the genus <em>Reissa</em> Evenhuis & Báez (Diptera: Mythicomyiidae: Mythicomyiinae) from the Eocene Green River Formation of North America, and discussion of biogeographical implications</strong></p>

The genus Reissa Evenhuis & Báez in Greathead & Evenhuis (2001) was originally described based on a short series of extant specimens from the island of Tenerife in the Canary Islands. No further species of the genus have been discovered since. A related fossil genus (Riga Evenhuis) was described from Eocene Rovno amber (Evenhuis, 2013) and has some characters in common with the fossil specimen but differs in thoracic and antennal features. The new species described and illustrated here is represented by a single compression fossil of the new species Reissa kohlsi sp. nov. from the Parachute Creek member of the Green River Formation of Wyoming/Utah/Colorado, USA, the site of which dates from 51.2–48.7 my (Smith et al., 2008). It marks the first fossil record of the genus and its first record from the New World, and the first fossil record of the family Mythicomyiidae from North America. The family was previously known in the New World fossil record from the Miocene Dominican amber (cf. Evenhuis, 2013), including two representatives from the Mythicomyiinae (Mythicomyia dominicana Evenhuis, 2002 and Pieza dominicana Evenhuis, 2002).

Prenatal developmental sequence of the skull of minke whales and its implications for the evolution of mysticetes and the teeth‐to‐baleen transition

Baleen whales (Mysticeti) have an extraordinary fossil record documenting the transition from toothed raptorial taxa to modern species that bear baleen plates, keratinous bristles employed in filter-feeding. Remnants of their toothed ancestry can be found in their ontogeny, as they still develop tooth germs in utero. Understanding the developmental transition from teeth to baleen and the associated skull modifications in prenatal specimens of extant species can enhance our understanding of the evolutionary history of this lineage by using ontogeny as a relative proxy of the evolutionary changes observed in the fossil record. Although at present very little information is available on prenatal development of baleen whales, especially regarding tooth resorption and baleen formation, due to a lack of specimens. Here I present the first detailed description of prenatal specimens of minke whales (Balaenoptera acutorostrata and Balaenoptera bonaerensis), focusing on the skull anatomy and tooth germ development, resorption, and baleen growth. The ontogenetic sequence described consists of 10 specimens of both minke whale species, from the earliest fetal stages to full term. The internal skull anatomy of the specimens was visualized using traditional and iodine-enhanced computed tomography scanning. These high-quality data allow detailed description of skull development both qualitatively and quantitatively using three-dimensional landmark analysis. I report distinctive external anatomical changes and the presence of a denser tissue medial to the tooth germs in specimens from the final portion of gestation, which can be interpreted as the first signs of baleen formation (baleen rudiments). Tooth germs are only completely resorbed just before the eruption of the baleen from the gums, and they are still present for a brief period with baleen rudiments. Skull shape development is characterized by progressive elongation of the rostrum relative to the braincase and by the relative anterior movement of the supraoccipital shield, contributing to a defining feature of cetaceans, telescoping. These data aid the interpretation of fossil morphologies, especially of those extinct taxa where there is no direct evidence of presence of baleen, even if caution is needed when comparing prenatal extant specimens with adult fossils. The ontogeny of other mysticete species needs to be analyzed before drawing definitive conclusions about the influence of development on the evolution of this group. Nonetheless, this work is the first step towards a deeper understanding of the most distinctive patterns in prenatal skull development of baleen whales, and of the anatomical changes that accompany the transition from tooth germs to baleen. It also presents comprehensive hypotheses to explain the influence of developmental processes on the evolution of skull morphology and feeding adaptations of mysticetes.

Systematic taxonomy of the Trilobatus sacculifer plexus and descendant Globigerinoidesella fistulosa (planktonic foraminifera)

The extant morphospecies of the Trilobatus sacculifer plexus (T. sacculifer, T. quadrilobatus, T. immaturus and T. trilobus) have widespread biogeographical distributions and long stratigraphical ranges, and are thus routinely utilized in palaeoceanographical studies. The descendant morphospecies Globigerinoidesella fistulosa is comparatively short-ranging (Pliocene–Pleistocene) and an important biostratigraphical marker. However, taxonomic concepts of these morphospecies are inconsistently applied between workers, leading to loss of information and incomparable datasets. We present a taxonomic appraisal of each morphospecies, including detailed taxonomic histories and refinement of their morphological concepts, using a combined population-based and typological approach. Morphometric data and scanning electron microscopy are used to illustrate morphological intergradation in the Trilobatus sacculifer plexus. The distinctive morphology of Globigerinoidesella fistulosa is shown to develop from T. sacculifer (as previously documented), but also from the other morphospecies in the plexus, providing the first fossil evidence demonstrating that the four morphospecies of the T. sacculifer plexus are the same species. Our new analyses support culturing and molecular genetic evidence from extant specimens that suggests the four T. sacculifer plexus morphospecies are the same biological species. However, we advocate using the four morphospecies concepts (T. sacculifer, T. quadrilobatus, T. immaturus and T. trilobus) and G. fistulosa, here refined, to increase their palaeoecological and biostratigraphical value.

The Late Pleistocene Orangutan from Tham Prakai Phet: New discoveries

This paper describes the collection of isolated orangutan fossil teeth identified in the newly excavated material from Tham Prakai Phet, a site located in the Chaiyaphum Province in northeast Thailand. The collection is composed of 18 isolated teeth belonging to Pongo. The morphology of the upper and lower teeth is similar to that of fossil and extant orangutans from mainland Indochina and Indonesia. Only the wrinkles on the occlusal surface are less pronounced and sometimes simpler than extant orangutans. The dimensions of the teeth fall in the range of variation of fossil and extant specimens, but the distribution of the crown areas of the Tham Prakai Phet specimens fall above the mean value observed for extant orangutans. This new collection of continental orangutans confirms the persistence of this taxa in this part of Thailand up to the late Pleistocene, and provides new data useful for understanding the evolution of this hominoid and advance in the reconstitution of the evolutionary lineage of Pongo. The size of the sample from Tham Prakai Phet is not sufficient to determine an accurate taxonomic attribution; pending the increase of the current sample, we attribute the material to Pongo sp. (Pongo aff. weidenreichi).

First Fossil of Rhinoclemmys Fitzinger, 1826 (Cryptodira, Geoemydidae) East of the Andes

We describe the first undisputable fossil of Rhinoclemmys (Cryptodira, Geoemydidae) east of the Andes, represented by an isolated nuchal bone found in one of the most important paleontological sites with association of fauna and humans (Muaco site, western Venezuela) from the Late Pleistocene of the southern Caribbean. The nuchal is complete and slightly wider (4.8 cm) than long (4.2 cm), preserving well-defined sulci of the cervical, vertebral 1, marginal 1, and pleural 1. Comparisons with extant and fossil specimens of Rhinoclemmys allow us to attribute this nuchal to Rhinoclemmys, albeit as an indeterminate species. The occurrence of Rhinoclemmys in the southern Paraguana Peninsula indicates that during the Late Pleistocene this region had environmental conditions that allowed the survival of these freshwater-terrestrially adapted reptiles, particularly of “paleo-springs” inside a semi-arid region.

Comments on the holotype of Alburnus kurui Mangit Yerli 2018 andre-description of A. carianorum Freyhof, Kaya, Bayçelebi, Geiger Turan, 2019 (Teleostei: Leuciscidae).

Article 16.4. of the International Code for Zoological Nomenclature (ICZN, 1999) requires that the fixation of name-bearing types for a new species to be explicit: "Every new specific and subspecific name published after 1999, except a new replacement name…, must be accompanied in the original publication 16.4.1. by the explicit fixation of a holotype,…..and 16.4.2. where the holotype or syntypes are extant specimens, by a statement of intent that they will be (or are) deposited in a collection and a statement indicating the name and location of that collection." That means that for species described after 1999, the holotype must be finally deposited in a collection and it is obligatory to indicate the name of the collection and where it is located.

A black Page in the French partridge's history: the melanistic variety of Red-legged Partridge Alectoris rufa

Summary. The melanistic variety of Red-legged Partridge Alectoris rufa was described from a small population in western France around the 1850s. In this region, the Red-legged Partridge population as a whole was hunted, but melanistic individuals were targeted for both private and museum bird collections, and by 1865 the variety was extinct in western France. An extensive search for extant specimens documented 13 melanistic birds in six museums, and their details are presented here. Remarkably, some of these specimens were collected in areas elsewhere in France or even in other countries. After 1915, the allele for melanism appears to have been lost within the Red-legged Partridge population as a whole, and we discuss possible reasons for this. ‘…, nous sommes persuade que cette perdrix qui tend a demeurer en Anjou [now Maine-et-Loire] se multipliera dans quelques annees, au grand contentement des amateurs de la chasse et de l'ornithologie.’ […, we are persuaded that this partridge which tends to remain i...

Stalked crinoids from Gan (Late Ypresian, southwestern France): exceptional stereom preservation, paleoecology and taxonomic affinities

Exceptionally well-preserved ossicles of xenomorphic stalked crinoids (Echinodermata) were found into the Late Ypresian clay of the Tuilerie de Gan (Pyrenees-Atlantiques, southwestern France). Three kinds of columnal articulation correspond to three different genera, including the new genus Eocenocrinus. These columnals are attributed to Paraconocrinus romanensis, Democrinus londinensis and Eocenocrinus hessi n. gen., n. sp. Associated benthic fauna as well as columnal characters related to water depth confirm an increasing depth to an epibathyal environment as previously suggested by mollusk and foraminifer associations. Paraconocrinus romanensis associated with Democrinus londinensis mark the maximum water depth, which did not exceed 300 m. Distal columnal series with proximal roots of P. romanensis and D. londinensis were collected with their ossicles connected, indicating that these species lived on a muddy bottom. E. hessi n. gen., n. sp. is suspected to have been attached on hard substrate. Without diagenetic crystallizing, the crinoid stereom and its micro-biocorrosion appear as in extant specimens. We attribute to Eocenocrinus n. gen. large columnals previously described from northeastern Italy and recognize two species: E. bayani n. gen., n. sp. (Middle Lutetian) and E. didymus (Priabonian). E. hessi n. gen., n. sp. may represent the oldest known species in the family Phrynocrinidae.

Rediscovery of Cylindera (Cylindera) uudata (W. Horn, 1915) (Coleoptera: Carabidae: Cicindelini) from Durango, Mexico: Systematics, Neotype Designation, and Recognition

We document the rediscovery of Cylindera (Cylindera) nudata (W. Horn, 1915), a rarely collected tiger beetle species, from Durango, Mexico, nearly a century after its description in 1879. This rediscovery is based on a single female collected in 1972, and is only the second known specimen. Images of this specimen are provided, together with an English translation of the original German description and a review of its nomenclature. The unique female specimen is here designated as neotype for this species because it is the only extant specimen known. The holotype, the sole male and sole specimen in the original description, was destroyed during World War II. The neotype is deposited at the Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA. The information presented here will assist tiger beetle taxonomists in recognizing this species should it ever be collected in the future in Durango, or from adjoining Mexican states.

Fossil snakes (Squamata, Serpentes) from the tar pits of Venezuela: taxonomic, palaeoenvironmental, and palaeobiogeographical implications for the North of South America during the Cenozoic/Quaternary boundary.

BackgroundTar seep deposits in South America historically are well-known for their rich record of fossil mammals, contrasting with only a few formal reports of reptile remains. Here we report a new snake fauna recovered from two tar pits from Venezuela. The fossil remains come from two localities: (a) El Breal de Orocual, which comprises an inactive tar seep estimated to be Plio/Pleistocene in age; and (b) Mene de Inciarte, an active surface asphalt deposit with an absolute age dating to the late Pleistocene.MethodsThe taxonomic identity of all specimens was assessed via consultation of the relevant literature and comparison with extant specimens. The taxonomic assignments are supported by detailed anatomical description.ResultsThe Mene de Inciarte snake fauna comprises vertebral remains identified as the genus Epicrates sp. (Boidae), indeterminate viperids, and several isolated vertebrae attributable to “Colubridae” (Colubroidea, sensu Zaher et al., 2009). Amongst the vertebral assemblage at El Breal de Orocual, one specimen is assigned to the genus Corallus sp. (Boidae), another to cf. Micrurus (Elapidae), and several others to “Colubrids” (Colubroides, sensu Zaher et al., 2009) and the Viperidae family.ConclusionsThese new records provide valuable insight into the diversity of snakes in the north of South America during the Neogene/Quaternary boundary. The snake fauna of El Breal de Orocual and Mene de Inciarte demonstrates the presence of Boidae, Viperidae, “colubrids”, and the oldest South American record of Elapidae. The presence of Corallus, Epicrates, and viperids corroborates the mosaic palaeoenvironmental conditions of El Breal de Orocual. The presence of Colubroides within both deposits sheds light on the palaeobiogeographical pattern of caenophidians snake colonization of South America and is consistent with the hypothesis of two episodes of dispersion of Colubroides to the continent.

Calicioid lichens and fungi in amber – Tracing extant lineages back to the Paleogene

Calicioid lichens and fungi are a polyphyletic grouping of tiny ascomycetes that accumulate a persistent spore mass (mazaedium) on top of their usually well-stalked ascomata (‘mazaediate fungi’). In addition to extant forms, six fossils of the group were previously known from European Paleogene amber. Here we report nine new fossils and analyze the preserved features of all fossils to assess their applicability for dating molecular phylogenies. Many fossils are extremely well preserved, allowing detailed comparisons with modern taxa. SEM investigation reveals that even fine details of ascospore wall ultrastructure correspond to those seen in extant specimens. All fossils can confidently be assigned to modern genera: three to Calicium (Caliciaceae, Lecanoromycetes), five to Chaenotheca (Coniocybaceae, Coniocybomycetes), six to Chaenothecopsis (Mycocaliciaceae, Eurotiales), and one to Phaeocalicium (Mycocaliciaceae, Eurotiales). Several Calicium and Chaenotheca fossils are assignable to specific lineages within their genera, while the Chaenothecopsis fossils demonstrate the extent of intraspecific variation within one such lineage. Some features in the morphology of Chaenotheca succina nov. sp. seem to be ancestral as they have not been reported from modern species of the genus.

Museum, Library and Archives Partnership: Leveraging Digitized Data from Historical Sources

The Museum of Comparative Zoology at Harvard University (MCZ), founded in 1859, has approximately 20 million extant and fossil invertebrate and vertebrate specimens. These historical collections continue to be a focus of research and teaching for the MCZ, Harvard and outside researchers. The Ernst Mayr Library/Archives (EMLA) of the MCZ is a founding member of the Biodiversity Heritage Library (BHL), an international consortium with a mission to make biodiversity literature openly available for use. Meeting the needs of the MCZ is a priority for EML Museum/library and achives collaboration One collaborative Museum/Library project was the digitization of approximately 81,000 MCZ specimen ledger pages/cards associated with various collections. These historical items, once digitized and deposited in the Harvard Digital Repository Service (DRS), were linked to the relevant specimen records in MCZbase, the museum-wide database. Over 1.2 million specimen records are now linked with digitized sources which benefit all users by adding to the provenance of the specimen data and allowing direct referral to the primary collection source. The EMLA holds an extensive collection of field notes, letters and manuscripts of researchers associated with the MCZ. Collector records are a gold mine of unpublished observations, notes, sketches, specimen lists and narratives. They are primary source data at its most personal, and may be the only documentation of a scientist’s thought processes and observations, particularly for unpublished materials. William Brewster was a prominent late 19th, early 20th century naturalist associated with the MCZ Ornithology Department until his death in 1919. Brewster provided authoritative and novel additions to the knowledge of birds, and his detailed, long-term observations are the key to his published contributions. Brewster’s unpublished scientific legacy is being digitized and deposited in the Harvard DRS and BHL by the EMLA. Transcribed notebook pages will be attached to images in BHL thus improving data discovery. Brewster deposited over 45,000 specimens in the MCZ Ornithology Collection. Combining specimens and unpublished notes is an opportunity to link hidden data and enhance research capabilities. Next steps for this collaborative project include finely grained cross-linking of specific pages, correspondence and photographs to and from the MCZ’s specimen database and BHL. We show how MCZ has leveraged data in digital repositories to enhance and directly relate to MCZbase, with citations to notes, transcriptions and published literature. These collaborations enhance discoverability of hidden data while promoting cross-discipline research to interrelated historical sources.

How does the curvature of the upper beak bone reflect the overlying rhinotheca morphology?

The beak has independently been evolved accompanied by the edentulism in many tetrapod linages, including extant Testudinata and Aves, and its form and function have been greatly diversified. The beak is formed by beak bones and the overlying keratinous cover, although their profiles are different from each other. Therefore, it is difficult to reliably reconstruct the entire profile of the beak in extinct taxa, whose keratinous tissues are rarely preserved. For elucidation of the morphological relationship between beak bone and overlying keratinous cover, we compared the curvature distribution of the culminal profiles of the upper beak bone and the overlying keratinous cover (rhinotheca) with each other using CT-scan, in 66 extant testudinatan and avian specimens (Aves: 33 genera, 24 families; Testudinata: 12 genera seven families). In both, rhinotheca and beak bone, the curvature of the profile was nearly constant rostral to a certain point, which was defined as the transition point, and the transition points of the rhinotheca and beak bone were close to each other. The profiles of the rhinotheca and beak bone rostral to their transition point were different in curvature and length. However, the ratio between the curvatures of rhinotheca and the beak bone strongly correlated with the arc angle of the rostral culminal profiles of the beak bone. The upper beak profile in extinct taxa is expected to be reconstructed more reliably using the abovementioned relationship between the beak bone and the rhinotheca.

Особливості росту сосни кедрової сибірської різного географічного походження у культурах 17-46-річного віку

Охарактеризовано особливості інтенсивності росту сосни кедрової сибірської 17-46-річного віку в загущених посадках залежно від місця збору насіння. Дослідження проведено у Караульному дільничному лісництві Навчально-дослідного лісгоспу Сибірського державного технічного університету (зелена зона м. Красноярська), 56°00` пн.ш., 92°30` сх.д., висота над рівнем моря становить 300 м. Дослідну ділянку створено садінням шестирічних сіянців за схемою 2 х 1 м. Сіянці вирощено з насіння, зібраного в популяціях Алтаю, Хакасії, Красноярського краю, Іркутської і Читинської областей. Середня висота дерев у 17-річному біологічному віці становила 2,2 м, у 28-річному – 7,1 м, у 46-річному – 15,9 м. Встановлено, що лідерські позиції за висотою і діаметром стовбура дерев змінюються залежно від віку. Так, 17-річні деревні рослини відрізнялися найбільшими показниками в шуміхінскому (місцевому) і північно-єнісейському варіантах. Дерева 28-46-річного віку мали перевищення за висотою та діаметром стовбура в шуміхінскому, алтайському, черемхівському, читинському варіантах (висота над рівнем моря становить 500-1000 м, пн.ш. – від 50°22` до 56°00`, сх.д. – 86°54`-108°43`). Відношення висоти дерева до діаметра стовбура змінювалося від 0,83 у 17-річному віці до 1,16 – у 46-річному. Відзначено збільшення співвідношення між висотою дерева і діаметром стовбура з віком, що свідчить про підвищену конкуренцію дерев. Кореляція між висотою, діаметром стовбура насіннєвого потомства і показниками материнських популяцій в перші роки вирощування відсутня; у 46-річному віці тіснота зв’язку між висотою, діаметром дерев і класом бонітету материнських популяцій помірна. До 46-річного віку в дослідних посадках відбувався природний відбір і збережені екземпляри, незалежно від географічного походження, відрізнялися кращими біометричними показниками. Проведено відбір кращих дерев для вирощування селекційного садивного матеріалу.
 До групи швидкорослих віднесено дерева читинського, алтайського, черемхівського і шумихінського походжень. Відсталі в рості дерева представляють північно-єнісейське, слюдянське і сонське походження. Відмінності підтверджуються показником достовірності (tф > t05).

Neogene tropical sea catfish (Siluriformes; Ariidae), with insights into paleo and modern diversity within northeastern South America

Herein we describe five new fossil species of the catfish family Ariidae: †Amphiarius paleoorinocoensis, †Ariopsis ariopsilus, †Bagre urumacoensis, †Sciades latissimum and †Sciades peregrinus from the late Miocene Urumaco Formation in Venezuela, South America. These identifications were based on comparison of morphological characters between the fossil skulls and the skulls of extant specimens from tropical America. The extant ariids from the Atlantic plume of the Orinoco-Amazon rivers reveal close taxonomic relationship to the fossil species. †Amphiarius paleoorinocoensis n. sp. and †Aspistor verumquadriscutis are closely related to Amphiarius rugispinis, Amphiarius phrygiatus and Aspistor quadriscutis, species endemic to areas under the influence of the Orinoco-Amazon plume. Another genus whose extant species are almost exclusively found in this region of the Atlantic is Sciades. Nevertheless, †Sciades latissimus n. sp. and †Sciades peregrinus n. sp., are closely related with Sciades dowii, found in the Pacific. This condition supports the extinction of Sciades dowii lineage in the Atlantic. The fossil †Ariopsis ariopsilus n. sp. shares many characters with extant species of the genus, which does not occur in the Amazon delta and which has no representative species in the Atlantic plume. The close relationship of †Bagre urumacoensis n. sp. to Bagre aff. marinus suggests a marine paleoenvironment with average to higher salinities. These new fossil catfish specimens from the Urumaco Formation suggest that they are ancestral lineages from both the Orinoco-Amazon Atlantic plume influence area ( Aspistor and Amphiarius) and the Caribbean-Western Pacific (Ariopsis), and extinct lineage of Sciades from the Atlantic.

A Post-pleistocene Calibrated Mutation Rate from Insect Museum Specimens.

Quantifying the age of recent species divergence events can be challenging in the absence of calibration points within many groups. The katydid species Neoconocephalus lyristes provides the opportunity to calibrate a post-Pleistocene, taxa specific mutation rate using a known biogeographic event, the Mohawk-Hudson Divide. DNA was extracted from pinned museum specimens of N. lyristes from both Midwest and Atlantic populations and the mitochondrial gene COI sequenced using primers designed from extant specimens. Coalescent analyses using both strict and relaxed molecular clock models were performed in BEAST v1.8.2. The assumption of a strict molecular clock could not be rejected in favor of the relaxed clock model as the distribution of the standard deviation of the clock rate strongly abutted zero. The strict molecular clock model resulted in an intraspecific calculated mutation rate of 14.4-17.3 %/myr, a rate substantially higher than the common rates of sequence evolution observed for insect mitochondrial DNA sequences. The rate, however, aligns closely with mutation rates estimated from other taxa with similarly recent lineage divergence times.