Miocene Of Chile Research Articles

Brazilian Miocene crabs II. A new genus and species (Crustacea: Decapoda: Brachyura) from Pirabas Formation, northern Brazil

In this study, we describe and illustrate Pirabacarcinus iaran. gen. n. sp., a novel species within the family Pilumnidae, collected from Miocene deposits of the Pirabas Formation, Brazil. Notably, this constitutes the first known fossil Pilumnidae from Brazil and only the second in South America, with the prior record from the Miocene of Chile. Pirabacarcinus iaran. gen. n. sp. is characterized by a series of distinct morphological characters, setting it apart from other known brachyuran species from the Pirabas Formation and other morphologically similar groups. The combination of a carapace with anterolateral margin longer than posterolateral margin, with three blunt spines anteriorly upturned; and a posterior region of carapace, including metabranchial and intestinal regions sloped, metabranchial region without lobes, and intestinal region reduced, faintly delimited set the new species apart from several brachyuran fossil genera. Opportunity is taken to describe and illustrate three cheliped fragments collected from the same locality of the new species.

A new taxonomic approach to Krithe Brady, Crosskey and Robertson, 1874 (Crustacea: Ostracoda) based on specimens from the Miocene of Chile

This study on Early Miocene species of Krithe from south-central Chile adopts a new taxonomic approach. The shape and number of posterior pits appear to be reliable diagnostic features that are especially useful in fossil specimens when recrystallization or infilling obscures the diagnostic anterodorsal radial pore canals (ADRPC). Based on this approach, three new species are proposed: Krithe dawnpetersonae n. sp., K. nerudai n. sp. and K. araucoensis n. sp. Moreover, additions are made to the diagnoses of Krithe dolichodeira van den Bold, K. sinuosa Ciampo, and K. dilata Ayress et al. Another two species of Krithe are kept in open nomenclature due to the scarcity of well-preserved adult specimens. This study reveals that some species of Krithe have wide geographic and stratigraphic distributions, while others have shorter ones.

Dinochelus steeplensis, a New Species of Clawed Lobster (Nephropidae) from the London Clay (Eocene) of England

A new species of clawed lobster, Dinochelus steeplensis, is reported from the London Clay (Eocene: Ypresian) of England. This is the first report of Dinochelus from the fossil record. The genus was previously known by one recent, deep-water species. Four genera, the fossil Oncopareia and extant Thaumastocheles, Thaumastochelopsis and Dinochelus, comprise the thaumastochelid lobsters, a cladistically cohesive group (minus Dinochelus) formerly given family-level status as Thaumastochelidae Bate, 1888. These lobsters are united, and readily distinguished from other nephropids, by their short, quadrate, pleonal pleura and by their major claw morphology (a short, bulb-like palm and very long, slender fingers bearing acicular dentition). Also described herein is an occurrence of Thaumastocheles sp. from the Miocene of Chile. We now have a monophyletic group of lobsters with a fossil record extending back 90 million years and, with the new fossils reported herein, morphologic end members connected by a range of intermediates. It seems certain that Oncopareia is the least derived of the thaumastochelids, and it is reasonable to conclude that Dinochelus and Thaumastocheles are intermediate between Oncopareia and the most derived genus, Thaumastochelopsis. The new fossil species, D. steeplensis, shows that the carapace and minor claw form of recent thaumastochelids had evolved by the early Eocene (ca. 52-58 mya), and that thaumastochelids were living in outer shelf depths at that time. The new species, being morphologically, stratigraphically, and bathymetrically intermediate between previously known fossil Oncopareia and recent thaumastochelids, is at least consistent with the previously hypothesized retreat of the thaumastochelids off of the shelf and into deeper waters in the Cenozoic.

Osteology of a new giant bony-toothed bird from the Miocene of Chile, with a revision of the taxonomy of Neogene Pelagornithidae

ABSTRACT Bony-toothed birds (Pelagornithidae) were among the largest volant birds, but their representatives from the upper size range have so far been known only from very fragmentary fossils. Here we report an exceptionally well-preserved giant species from the late Miocene of the Bahía Inglesa Formation in northern Chile, in which most major limb bones are complete and uncrushed. The fossil has the longest wing skeleton of any bird, and its wingspan in life was at least 5.2 m. Mass estimates of 16–29 kg are, however, surprisingly low and within the range of large extant volant birds, or only moderately above. The fossil constitutes the most substantial record of the Pelagornithidae (bony-toothed birds), and is assigned to a new species, Pelagornis chilensis. It is one of the largest known pelagornithids and the three-dimensionally preserved bones allow recognition of many previously unknown osteological features, especially concerning the vertebrae, pectoral girdle, and limb elements. We revise the taxonomy of Neogene pelagornithids and propose classification of all Miocene and Pliocene species into a single genus, Pelagornis. Osteological features are highlighted in which giant Neogene Pelagornithidae differ from their smaller Palaeogene relatives.

A review of the systematics, biogeography, and evolutionary relationships of Recent and fossil brachiopods of the Superfamily Kraussinoidea Dall, with descriptions of two new fossil species from New Zealand and Chile

ABSTRACTA review is presented of the genera and species, both living and fossil, comprising the Superfamily Kraussinoidea and of their geographic and stratigraphic distributions. Two new fossil species are described, Kraussina chilensis and Megerlina miracula, from the Miocene of Chile and New Zealand respectively. The ontogenetic development of the brachidium in each of the four kraussinid genera is described and on the basis of recognised differences it is proposed that a new taxonomic subdivision is made that places Megerlia in a new subfamily Megerliinae, distinct from the other three genera in the existing subfamily Kraussininae Dall. The loop ontogeny of kraussinoids is compared with that of other terebratellidines and a phylogenetic linkage between kraussinoids and laqueoids is suggested.

Miocene Vetigastropoda and Neritimorpha (Mollusca, Gastropoda) of central Chile

Species of Vetigastropoda (Fissurellidae, Turbinidae, Trochidae) and one species of Neritimorpha (Neritidae) from the Navidad area, south of Valparaı́so, and the Arauco Peninsula, south of Concepción, are described. Among these, the Fissurellidae comprise Diodora fragilis n. sp., Diodora pupuyana n. sp., two additional unnamed species of Diodora, and a species resembling Fissurellidea. Turbinidae are represented by Cantrainea sp., and Trochidae include Tegula (Chlorostoma) austropacifica n. sp., Tegula (Chlorostoma) chilena n. sp., Tegula (Chlorostoma) matanzensis n. sp., Tegula (Agathistoma) antiqua n. sp., Bathybembix mcleani n. sp., Gibbula poeppigii [Philippi, 1887] n. comb., Diloma miocenica n. sp., Fagnastesia venefica [Philippi, 1887] n. gen. n. comb., Fagnastesia matanzana n. gen. n. sp., Calliostoma mapucherum n. sp., Calliostoma kleppi n. sp., Calliostoma covacevichi n. sp., Astele laevis [Sowerby, 1846] n. comb., and Monilea riorapelensis n. sp. The Neritidae are represented by Nerita (Heminerita) chilensis [Philippi, 1887]. The new genus Fagnastesia is introduced to represent low-spired trochoideans with a sculpture of nodes below the suture, angulated whorls, and a wide umbilicus. This Miocene Chilean fauna includes genera that have lived at the coast and in shallow, relatively warm water or deeper, much cooler water. This composition therefore suggests that many of the Miocene formations along the central Chilean coast consist of displaced sediments. A comparison with different fossil and Recent faunas from around the Pacific and South America indicates that the vetigastropod and neritid fauna from the Miocene of Chile has only minor affinities with taxa living near New Zealand, Argentina, and the tropical eastern Pacific at that time.