|
Slender-snouted Crocodile
''Mecistops'' is a genus of crocodiles, the slender-snouted crocodiles, native to sub-Saharan Africa. Taxonomy and etymology Traditionally placed in ''Crocodylus'', recent studies in DNA and morphology have shown that it is in fact basal to ''Crocodylus'', thus was moved its own genus. This genus itself was long considered to contain only one species, '' M. cataphractus'', but recent genetic analysis has revealed the existence of two species: the West African slender-snouted crocodile (''M. cataphractus'') and the Central African slender-snouted crocodile (''M. leptorhynchus''). Both species diverged during the Miocene (about 6.5–7.5 million years ago) and are separated by the Cameroon Volcanic Line. Phylogeny The cladogram below is based on two studies that combined morphological and molecular (DNA sequencing) data. (Note that most morphological analyses find a closer relationship between ''Euthecodon'' and ''Brochuchus''.) Alternatively, other morphological studies h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, colour, pattern, size), i.e. external morphology (or eidonomy), as well as the form and structure of the internal parts like bones and organs, i.e. internal morphology (or anatomy). This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Friedrich Burdach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodylus Anthropophagus
''Crocodylus anthropophagus'' is an extinct species of crocodile from the Pleistocene of Tanzania. It lived 1.84 million years ago. It was a large-sized predator reaching a length of . Etymology ''Crocodylus anthropophagus'' was first named by Christopher A. Brochu, Jackson Njau, Robert J. Blumenschine and Llewellyn D. Densmore in 2010. The specific name ''anthropophagus'' is from Greek word "''anthropos''" that means "human" and Greek word "'" that means "eater", in reference to the evidence that this animal included hominids in its diet. Taxonomy The holotype specimen, NNHM-1001, comprises a skull and partial skeleton. All specimens were discovered in Olduvai Gorge, Tanzania, in two different rock formations dating to 1.845 and 1.839 million years ago in the Plio-Pleistocene. The cladogram below is from a 2021 study based on the finding of a new ''C. anthropophagus'' partial cranium. Description The skeleton is consistent with living representatives of the genus. The a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voay
''Voay'' is an extinct genus of crocodile from Madagascar that lived during the Late Pleistocene to Holocene, containing only one species, ''V. robustus''. Numerous subfossils have been found, including complete skulls, noted for their distinctive pair of horns on the posterior, as well as vertebrae and osteoderms from such places as Ambolisatra and Antsirabe. The genus is thought to have become extinct relatively recently. It has been suggested to have disappeared in the extinction event that wiped out much of the endemic megafauna on Madagascar, such as the elephant bird and Malagasy hippo, following the arrival of humans to Madagascar around 2000 years ago. Its name comes from the Malagasy word for crocodile. Description One unusual feature of ''V. robustus'' that distinguishes it from other crocodilians is the presence of prominent "horns" extending from the posterior portion of the skull. They are actually the posterolaterally extended corners of the squamosal bone. Other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodylinae
Crocodylinae is a subfamily of true crocodiles within the family Crocodylidae, and is the sister taxon to Osteolaeminae ( dwarf crocodiles and slender-snouted crocodiles). Taxonomy Crocodylinae was cladistically defined by Christopher Brochu in 1999 as ''Crocodylus niloticus'' (the Nile crocodile) and all crocodylians more closely related to it than to ''Osteolaemus tetraspis'' (the Dwarf crocodile). This is a stem-based definition, and is the sister taxon to Osteolaeminae. Crocodylinae contains the extant genus '' Crocodylus''. It is disputed as to whether is also includes ''Mecistops'' (slender-snouted crocodiles), or the extinct genus Voay. Phylogeny Some morphological studies have recovered ''Mecistops'' as a basal member of Crocodylinae, more closely related to '' Crocodylus'' than to ''Osteolaemus'' and the other members of Osteolaeminae, as shown in the cladogram below. The below cladogram is based on a 2021 study using paleogenomics that extracted DNA from the ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Crocodile
The dwarf crocodile (''Osteolaemus tetraspis''), also known as the African dwarf crocodile, broad-snouted crocodile (a name more often used for the Asian mugger crocodile) or bony crocodile, is an African crocodile that is also the smallest extant (living) species of crocodile. Taxonomy and etymology The second species has had a somewhat convoluted taxonomical history. It was first described as ''Osteoblepharon osborni'' by Schmidt in 1919, based on a few specimens from the Upper Congo River Basin in what is now the Democratic Republic of Congo. However, Inger in a 1948 paper found the specimens wanting of characteristics that would justify a generic separation from ''Osteolaemus'' and referred the specimens to '' Osteolaemus osborni''. In 1961, it was reduced to subspecies rank. A study of morphology published in 2007, and studies of DNA in 2009, 2013 and 2015 indicate that three distinctly different populations of ''Osteolaemus'' may merit full species recognition. These are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osborn’s Dwarf Crocodile
''Osteolaemus osborni'', commonly known as Osborn's dwarf crocodile, is a species of crocodile endemic to the Congo Basin in Africa. This species has had a somewhat convoluted taxonomical history. It was first described as ''Osteoblepharon osborni'' by Schmidt in 1919, based on a few specimens from the Upper Congo River Basin in what is now the Democratic Republic of Congo. However, Inger in a 1948 paper found the specimens wanting of characteristics that would justify a generic separation from ''Osteolaemus'' and referred the specimens to ''Osteolaemus osborni''. In 1961, it was reduced to subspecies rank, but was revalidated to full species status in 2021. The subspecific name, ''osborni'', is in honor of American paleontologist Henry Fairfield Osborn Henry Fairfield Osborn, Sr. (August 8, 1857 – November 6, 1935) was an American paleontologist, geologist and eugenics advocate. He was the president of the American Museum of Natural History for 25 years and a cofounder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rimasuchus
''Rimasuchus'' is an extinct genus of crocodile from the Miocene of Egypt and possibly Libya. Only one species - ''Rimasuchus lloydi'' - is currently known. It was previously thought to be a species of ''Crocodylus'', but is now thought to be more closely related to the modern African dwarf crocodiles (''Osteolaemus''). History and naming The first fossil of ''Rimasuchus'' an incomplete skull with associated mandible, was collected by lieutenant colonel Arthur H. Lloyd in the early 20th century in Wadi Moghara, Egypt. The holotype specimen, CGM 15597, was given to the Egyptian Geological Museum and described by Fourtau in 1920 under the name ''Crocodylus lloydi''. Other material includes an uncatalogued skull housed at the Natural History Museum, London (likewise from Wadi Moghara) and fossils found at Gebel Zelten in Libya. Eventually other skulls further south in Africa ended up being assigned to ''"Crocodylus" lloydi'' , with the oldest and southern-most material stemming fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteolaeminae
Osteolaeminae is a subfamily of true crocodiles within the family Crocodylidae containing the dwarf crocodiles and slender-snouted crocodiles, and is the sister taxon to Crocodylinae. Taxonomy Osteolaeminae was named by Christopher Brochu in 2003 as a subfamily of Crocodylidae separate from Crocodylinae, and is cladistically defined as ''Osteolaemus tetraspis'' (the Dwarf crocodile) and all crocodylians more closely related to it than to ''Crocodylus niloticus'' (the Nile crocodile). This is a stem-based definition, and is the sister taxon to Crocodylinae. Osteolaeminae contains the two extant genera ''Osteolaemus'' and ''Mecistops'', along with several extinct genera, although the number of extant species within Osteolaeminae is currently in question. Phylogeny The cladogram below is based on two studies that combined morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data. Alternatively, other morphological studies have recovered ''Mecistops'' a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, which includes the most recent common ancestor of all modern birds, and all of its extant or extinct descendants. The concept was developed by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms relative to their extinct relatives in his "Die Stammesgeschichte der Insekten", and the "crown" and "stem" group terminology was coined by R. P. S. Jefferies in 1979. Though formulated in the 1970s, the term was not commonly used until its reintroduction in 2000 by Graham Budd and Sören Jensen. Contents of the crown gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodylidae
Crocodiles (family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to include all extant members of the order Crocodilia, which includes the alligators and caimans (family Alligatoridae), the gharial and false gharial (family Gavialidae) among other extinct taxa. Although they appear similar, crocodiles, alligators and the gharial belong to separate biological families. The gharial, with its narrow snout, is easier to distinguish, while morphological differences are more difficult to spot in crocodiles and alligators. The most obvious external differences are visible in the head, with crocodiles having narrower and longer heads, with a more V-shaped than a U-shaped snout compared to alligators and caimans. Another obvious trait is that the upper and lower jaws of the crocodiles are the same width, and the teeth in the lower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brochuchus
''Brochuchus'' is an extinct genus of crocodile known from the Early Miocene Hiwegi Formation of Rusinga Island in Lake Victoria, Kenya; it was originally named as a species of ''Crocodylus''. It contains two species, ''B. parvidens'' and ''B. pigotti''. ''Brochuchus'' belongs to the family Crocodylidae, which includes all living crocodiles. The closest living relative of ''Brochuchus'' is ''Osteolaemus'', the dwarf crocodile. Compared to ''Osteolaemus'', which has a small body and blunt snout, ''Brochuchus'' has a more generalized crocodylid anatomy. ''Brochuchus'' is characterized by a flat and relatively narrow skull, and although it is larger than ''Osteolaemus'' it is smaller than most other crocodylids. It has two prominent bumps on the surface of its snout. The genus was named in honor of Christopher A. Brochu, for his scientific work on Crocodylia and its relatives. The unusual combination and spelling are intended as an auditory and visual pun such that the ‘ch’ soun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
