22 August 2017
There are not many papers hosted online featuring Megalibgwilia. Considering that these echidna ancestors have been known and described for almost 150 years, the lack of modern articles is somewhat sad and almost depressing. There are plenty of articles that make passing mentions of Megalibgwilia or compare the "giant echidnas" to extant members of the genus. One of the original articles describing Megalibgwilia by Owen in 1883 originally named the animal Echidna ramsayi and consisted of less than a half page of text. That abstract of a lecture by Professor Owen can be viewed in the archives of the Proceedings of the Royal Society here. Unfortunately, Dun's 1896 description of the other species, Megalibgwilia robusta, has not been hosted anywhere online. Print copies may be nearly impossible to find as well given the age.
20 August 2017
Megalibgwilia is an unusual animal for a variety of reasons. Some of these reasons are detailed in the facts that are know about the animal and shared on various websites and fact pages. There are a number of sites we have used before and many that many among us may have never heard of before that host files, short essays, and illustrations of the two species of this genus. The first of these familiar sites which appears in a search is the Dinopedia. Despite this animal clearly being a monotreme, a type of non-placental mammal now represented by only extant echidnas and the Platypus, the Dinopedia entry is fairly comprehensive and discusses Megalibgwilia almost identically as sources like Wikipedia. This makes it neither more nor less useful than Wikipedia of course. Wikispecies entries for the animals are taxonomically useful, but again, this information can be found in Wikipedia as well. A slightly more detailed history of taxonomy is available on the Fossilworks site which also provides some locality details for known fossils as well. One of the most interesting new sites is the Australian Broadcasting Corporation's site discussing the extinction of megafauna in Australia. While it does not specifically discuss Megalibgwilia exclusively, this site does discuss the environment it lived in and how it may have been subjected external and internal pressures leading to its extinction.
19 August 2017
In looking for new animal this week we are going out of our normal range and into the time of the mammals. Becoming extinct approximately 50,000 years ago during the Pleistocene, the tachyglossid (a group that includes the extant genera of Echidnas) Megalibgwillia consists of two species, M. ramsayi (Owen, 1884) and M. robusta (Dun, 1896), and represents the oldest known echidna genus found. Both species are often referred to as the "giant echidna" but recent evidence shows that they are approximately the same size as the largest living echidnas rather than immense fossil animals, respective to extant echidna. Both species are represented by largely complete fossils and, because we know basically what the animals looked like, we can state that they were most likely as bizarrely intriguing as extant echidnas.
17 August 2017
16 August 2017
At least one site mentions that Conchoraptor remains have been discovered with attached feathers. These feathers have been described sparingly, but have been described as sexually dimorphic characters of Conchoraptor. Sexually dimorphic characters are typically most reliable in adult animals. The assumption with the assertion that the feathers represent dimorphism is that they most likely came from adult specimens. One of the hypotheses of discerning adults from juveniles and sub-adults in Conchoraptor is less concerned with feathers and sexual dimorphism and more concerned with the crest on the cranium. Most oviraptorids possess a large crest along the midline of the skull that is larger rostrally than caudally. The original material lacks a crest entirely and remains recovered later also appear to lack crests or possess very minimal crests. The hypothesis that crests grew as the dinosaur aged are not abnormal or new, but without known fully adult specimens possessing full crests, we can neither, as yet, support nor refute that hypothesis. However, if evidence comes to light to fully support this and the hypothesis concerning dimorphism and feather morphology, then we will know a lot more about the life histories of these animals.
15 August 2017
Brains and other soft tissues are of great interest to scientists in extant and fossil specimens. There are a variety of ways to study organs in extant specimens and many of those methods can actually be applied to fossil specimens as well. Many of the methods used to investigate fossil soft tissue systems originate in studies of the soft tissues of extant organisms. These are systems that we can readily devise methods for and test out the methods on. Interpretation of the results can be compared with observations of behavior and organ use in extant animals as well. These model organisms and their organ systems allow for inquiries into similar systems in fossil animals. These steps result in studies such as Kundrat 2007 which looks at virtual brain models of Conchoraptor derived from CT scans of the skull. The scans are used to create virtual endocasts, or models of the negative space of the skull where the brain would have been in a living Conchoraptor. Endocasts show scientists potential lobes of the brain (assuming that the skull retained its original dimensions during the fossilization process). Kundrat 2007was able to identify characteristics of the brain that Conchoraptor appears to have shared, or at least approximated, with the brains of birds. Additional studies of the skull have been undertaken which look at other organ systems of Conchoraptor and use some similar methods. Kundrat and Janacek 2007 explored the hearing capabilities as well as the structure of the skull of Conchoraptor. They described pneumatization and sinuses of the cranium (another avian-like feature). This study also described and analyzed the bones surrounding the tympanum (eardrum). Recesses in the bone helped to describe the tympanum itself as well as the different portions of the ear. Specifically, Kundrat and Janacek were able to describe distinct proportions and geometry of the inner and middle ear of Conchoraptor and infer the hearing capabilties of the dinosaur.