Friday 20 November 2015

Fumicollis hoffmani: A new species of Hesperornithiform Bird from the Late Cretaceous Niobrara Chalk of Kansas.

The Hesperornithiforms were a distinctive group of toothed Birds that appeared in the Early Cretaceous and persisted till the end of that period. They are thought to have been among the first Birds to adapt to an aquatic lifestyle, apparently having been powerful swimmers with proportion driven by the enlarged hind legs, though like other Cretaceous toothed Bird groups they are not thought to have any living descendants.

In a paper published in the journal PLoS One on 18 November 2015, Alyssa Bell and Luis Chiappe of the Dinosaur Institute at the Natural History Museum ofLos Angeles County, describe a new species of Hesperornithiform Bird from the Late Cretaceous Smoky Hill Member of the Niobrara Chalk of Kansas.

The species is named Fumicollis hoffmani, where 'Fumicollis' means 'Smoke Hill' in Latin and 'hoffmani' honours Karen and Jim Hoffman for their generous support of the Natural History Museum of Los Angeles County and in particular the Dinosaur Institute. The species is described from a single specimen, which was initially discovered in 1937 and thought to be a specimen of Baptornis advenus, but which has now been shown to be a separate species. The specimen comprises eight vertebrae, numerous fragments of ribs, plus most of the ilium, ischium, and pubis, some of the left half of the pelvis, part of the pygostyle (tailbone made from fused vertebrae), most of the left hindlimb and part of the right.

Reconstruction of Fumicollis hoffmani. Bell & Chiappe (2015).

Fumicollis hoffmani shows a mixture of traits seen in other Late Cretaceous Hesperornithiforms and more 'primitive' traits seen in earlier members of the group. However Bell and Chiappe believe that the 'primitive' traits of Fumicollis hoffmani relate to its size; most known Late Cretaceous Hesperornithiforms were quite large, while earlier members of the group were generally small.

The Smokey Hills Member is thought to have been laid down over a period of about five million years, but has produced a rich and diverse assemblage of Hesperornithiforms. This does not necessarily mean that all the species were present at the same time, though it leaves a very limited period for different species to replace one-another. Bell and Chiappe suggest that the diverse assemblage potentially represents an assemblage of Birds with different ecological requirements living in the same area. This can be seen today in Penguins around the Antarctic Peninsula and nearby islands, where up to six different species can be found living in the same area. While the Penguins are all essentially similar, being aquatic Birds feeding on Fish, the different species are all different sizes, and therefore feed at different depths, allowing the different species to live in the same area without directly competing with one-another.

See also... feathers in an Enantiornithine Bird from the Early Cretaceous Crato Formation of Brazil.                                                                               While feathers have been known in fossil Birds from... stomach contents in Early Cretaceous Ornithuromorph Birds.                     The Early Cretaceous Jehol Group of China has produced a remarkable number of well-preserved fossils of Mesozoic Birds, adding greatly to our understanding of the early history of this group... eggs from a Late Cretaceous colonial nesting site in Argentinean Patagonia.                In the 1980s a large collection of Avian eggs were uncovered at the campus of the National University of Comahue at Neuquén City in Argentinean Patagonia. These ages were located on a single bedding...

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