|MESOZOIC MAMMALS; Gondwanatheria, an internet directory:|
PLEASE NOTE: THIS PROJECT IS NOT SCIENTIFIC. IT IS A HOBBY.
"I was looking for information on an old mammal and found this lot. What is this project?"
It's got lots of information on old mammals. For a short bit of background information, see here.
In 1987, Mones referred Gondwanatheria to
Multituberculata. This was originally widely accepted but then subsequently widely
rejected. However, beginning from about 2005, various gangs of researchers began revising
that rejection to some degree or other. Multi affinities seem to be back in the ring, either
as full blown multis or allies. The background to all this is rather complicated. This
directory should now be written from a perspective of gondwans as possible multis. What's
also possible is that I may have neglected to emend older parts of the text.|
Hopefully, at some stage, I'll also find time to build in more information from Gurovich's 2005 thesis on these critters, and their possible place in ancient Mammaldom. It's a work of epic proportions weighing in at over 600 pages, and packed full of details and discussion.
Introducing the gondwans
A possible early representative has been reported from the Cretaceous of Tanzania, (Krause et al, 2003). This referral is 'very tentative'. Further details can be found in the Other Reports section.
Original citation: Mones (1987), Gondwanatheria, un nuevo orden de Mamíferos Sudamericanos (Mammalia: Edentata: ?Xenarthra). Comunicaciones Paleontológicas del Museo de Historia Natural de Montevideo, 18, p.237-240.
What Gurovich and Beck, 2008 came up with
Mikko Haaramo's Allotheria
A quick guide to multidom, assuming that's what godwanatherians were.
Jeff Poling, Geological Ages of Earth History
A long, long time ago...
Order Xenarthra, The University of Michigan
In case this taxon indeed turns out to be somewhere near the origins of edentates, here's a guide to what happened later; armadillos, sloths and anteaters.
Journal of Vertebrate Paleontology, 19(2), 1999, p.373
Pascual R, Goin FJ, Krause DW, Ortiz-Jaureguizar E, & Carlini AA. The first gnathic remains of Sudamerica... 'Gnathic' refers to the jaw.
Palaeos, Allotheria, The Vertebrates, Toby White
Details on the dentistry.
Vucetichia (= Ferugliotherium),
Upper Cretaceous: Argentoides, Bharattherium, Ferugliotherium, Gondwanatherium, Lavanify, Trapalcotherium, Tanzania (maybe)
Kielan-Jaworowska Z, Ortiz-Jaureguizar E, Vieytes C, Pascual R & Goin FJ, 2007|
Remarks: Update 2008, warning
|Species:||Argentodites coloniensis Kielan-Jaworowska et al, 2007|
|Place:||La Colonia Formation, Patagonia|
|Remarks:||The following is based upon my reading of
Kielan-Jaworowska et al, 2007.|
At first, it's tempting to think this multi was part of a North South faunal exchange system operating at some time during the latter parts of the Upper Cretaceous. Dinosaurs are known to have migrated in both directions, and marsupial and placental mammals may have come south at around the same sort of time. The diversity of South American marsups during the lower Paleocene would be in line with that. Given those circumstances, it wouldn't be all too surprising if a line of multis had also migrated then, and perhaps one did. However, if Argentodites resulted from such an event, then its North American ancestral lineage happens to be unknown. It has no obvious links with any fairly contemporary multi family there. Actually, there's even room for doubting its cimolodontan credentials. The referral is no more than tentative. Some "plagiaulacidan" tendencies are also evident. In short, you'd hope that a relatively recent immigrant would carry luggage indicative of its line of origin; its pedigree. While Argentodites clearly must have such useful pointers, quite where they're pointing to isn't obvious. Should its ancestors indeed have scampered off down south, they could have done so many millions of years prior to its birth. That would be one way of accounting for its eccentricities.
Multi-plication in South America
When I first saw the title of this paper, I rapidly reached a wrong conclusion. It's been known for ten years that some multi remains have been found in Los Alamitos Formation of Patagonia, and I blithely assumed that would be the subject here. Those fossils had been originally assigned to what was thought to be a gondwanatherian multi. However, it then became clear that gondwanatherians weren't multis, but some of the fossils concerned were. Those are the first known traces of Mutltidom from South America and, seemingly in contrast to Argentodites and the rest of known contemporaries, they apparently stem from a "plagiaulacidan" rather than a cimolodontan.
However, that's not the subject of this study. It concerns a p4 premolar from a bit further south in Patagonia; La Colonia Formation. And this tooth seems to stem from an eccentric cimolodontan. Two multis must've been padding around during the latter years of the Argentinean Upper Cretaceous, although the first one spotted remains nameless (p.257).
There's a point that's well worth bearing in mind for this pair. In both cases, the referrals to the two branches of Multidom are tentative, a ?plagi and a ?cimolo. The fossil record for mammals from the southern hemisphere contains vast blank spaces for much of the Mesozoic and, as evidence slowly emerges to fill them to some degree, the picture could change radically.
Not much to go on Very little is known of this 'Argentinean traveller'; just a single lower tooth. While hardly enough to form the basis of a photo-fit picture, it does provide some basis comparisons. It's a lower p4 premolar refined, as for all but the most basal of multis, for slicing up food. Seen from the side, the front wall of the tooth is prodigiously rounded, it bulges, and that's typical for cimolodontans. The length reaches a respectable 4.15 millimetres while the maximum width attains 1.35.
Some speculation can be involved with isolated teeth when attempting to work out which was round the things went, but considerably less than might be thought. Teeth are functional members of working crews, and they have to be consistent with the rules dictated by nature as well as traits provided by ancestry. This can produce distinct characters for uppers and downers, fronts and backs and so on. Seen from the side, one end of this tooth bulges proudly outwards. The margin of the other end is much straighter. That bulge is consistent with the front of cimolodontan p4s, an affinity which is further supported by the organisation of enamel prisms. The authors term that "normal" (p.258). However, the straightness of the wear wall, and the relatively level height along the top of the crown happen to be more akin to some "plagiaulacidans". Cimolodontan models are generally shaped like the outline of an arch.
A more difficult challenge is provided by attempting to work out whether it's a left or right premolar. The buccal and lingual sides happen to be unusually similar; not the case for known northern cimolodontans with relatively large p4s. Tentatively, the authors opted for a left tooth with its buccal side somewhat less convex than the lingual one. What's presumably a cusp at the rear of the buccal side was less helpful than could've been hoped. There's a labial one as well, but what it was for isn't known.
Roots and ridges
The roots have gone but two were present (p.260). As generally for cimolodontans, but not for "plagiaulacidans", the front root was wider.
The roof of the tooth is adorned with eight serrations. Only the last of them shows much wear, and that suggests the former owner can't have lived until a grand old age. This premolar didn't do all that much work. Ridges run down from the serrations on both flanks, and the presumed buccal ones are more strongly developed than their lingual partners.
MPEF 604, the only specimen presently known, is a near complete but rootless lower premolar in the growing collection of the Museo Paleontológico Edgidio Feruglio, Trelew. Its specific name honours La Colonia Formation.
|Reference:||Kielan-Jaworowska Z, Ortiz-Jaureguizar E, Vieytes C, Pascual R & Goin FJ (2007), First ?cimolodontan multituberculate mammal from South America, Acta Palaeontologica Polonica, 52(2), p.257-262.|
Acta Palaeontologica Polonica 52(2)
Kielan-Jaworowska et al, 2007 is presently freely accessible in pdf format.
Prasad GVR, Verma O, Sahni A, Krause DW, Khosla A & Pamar V, 2007|
Family: Sudamericidae Scillato-Yané & Pascual, 1984
Remarks: Bharat is a Sanskrit word for 'India' and therion is Greek for
|Species:||Bharattherium bonapartei Prasad et al, 2007|
|Place:||Kisalpuri, Madhya Pradesh, & Naskal, Andhra Pradesh, Deccan Traps|
|Age:||Maastrichtian, Upper Cretaceous|
|Remarks:||The following is based upon my reading of
Prasad et al, and thanks are due to Omkar for both forwarding the paper and further
advice during a fairly confused day. I mean, there I was looking at a second
description from another team, thinking: "I can't see any difference!" That was three
days after having read this paper. Thanks also go to Greg Wilson for supplying that
one and further welcome advice. And congratulations are awarded to Mikko Haaramo for
noticing one of the specimens featured in both studies. Still, I think I've just
about recovered now. These notes were mainly written prior to hearing about the
second publication which I haven't yet read. It established Dakshina jederi.|
Getting on with the story
Despite the most recent know gondwanatherian having died about forty million years ago in the then lushly forested nature reserve of Antarctica, these herbivorous mammals remain maddeningly shy of human company. This can't be put down as some kind of survival instinct. It's sheer bloody mindedness. Their known fossil record spans about thirty million years (which isn't actually all that long in comparison to some lineages I could mention) but, even at their most daringly revealing, they've not yet allowed more than a tantalizing glimpse of a partial lower jaw. Generally, rather than going all the way and exposing the glories of their full naked bodies, they draw the line at isolated teeth. Ladies, I assure you, your chances are better for getting a monk out of his habit than can be said for your prospects of seeing a gondwanatherian in its birthday suit.
All the more reason for pleasure then, when a new gondwanatherian adds enrichment to the slowly unfolding story. These enigmatic mammals -whatever their wider affinities may have been- were, in some respects, millions of years ahead of their time; precocious exponents of then unprecedented methods of food exploitation. Quite what their food was is also unclear.
Excepting for Ferugliotherium, known gondwanatherians had high crowned teeth of a style known as hypsodont (p.17), with basically flat occluding molar surfaces excepting for corrugations provided by transverse lophs or other deliberate irregularities, such as in this case. These teeth were open rooted and the shape of the occlusal outline would, in some instances, provide suitable inspiration for aliens in a game of Space Invaders. The genus of Sudamerica is particularly tempting; a kind of melted H shape with additional smaller vertical bars on each side. Wear on the lophs even provides it with a belt of circles running horizontally along the middle, and they're crying out to be converted into spooky eyes or flashing lights on a spaceship.
(Note to myself: for the open-rootedness of Gondwanatherium and Sudamerica see page 301 of Gurovich, 2005).
There have been conflicting interpretations on gondwanatherian affiliations, but all have shared one essential component. They were wrong. One view saw them as perhaps related to placental xenarthrans, armadillos and the like. Another held them to be eccentric multituberculates. Multi affinities were actually correct for some fossils tentatively referred to the genus of Ferugliotherium, but not for the genuine generic fossils. Multidom was also kicked entirely out of consideration by a description of a gondwanatherian jaw in 1999. Although it lacked the tooth crowns, it had originally sported four molars, and that's twice the number allowed for multis. Finally, a form of consensus has emerged. Everybody now agrees that nobody has the foggiest idea of gondwanatherian affinities beyond them being small, plant-eating mammals of some kind or other. It's clear they were spread far and wide across the southern hemisphere landmasses for some time, but the known fossil record's thin, and in no fauna are they common.
Indian Upper Cretaceous mammals
At least three Maastrichtian aged localities in Central India are now contributing to knowledge about mammals from near the end of the Cretaceous (p.19). Two of these are close to one another and found about 70km west of Hyderabad: Naskal and Rangapur. A third, Kisalpuri, has been discovered more recently and radically extends the fossil front under assault by paleontologists -the intertrappean beds- around 700km further north. Presumably, the intervening stretch of land is presently hiding further localities. Research at Kisalpuri has so far yielded around fifty isolated teeth and bones of mammals, and most are from eutherians. One tooth, however, is gondwanatherian. A poorer specimen has previously turned up at Naskal and it belongs to the same species. Meanwhile, other researchers appear to have arrested some more.
'Indian beast' has been referred to the gondwanatherian family of Sudamericidae, and that might puzzle some present day geographers. However, sudamericids are now known to have inhabited a much wider area then the name might suggest. It's the smallest known member, with the holotype being around 65% the size of the Malagasy Lavanify, an approximate contemporary. (To undermine that, I've got to point out the type of Dakshina is larger than the molar described by these authors and, should it happen to be the corresponding tooth in the set, the size 'difference' between these two could disappear. Officially, however, D. is presently a separate genus.) The occlusal outline of the molar is termed "sub-rectangular" and, looking at the actual shape, that'd surprise some geometrists. It's rather rounded as sub-rectangles go. The crown features a wide 'v'-shaped island of dentine, as also known from Lavanify but, in this case, it contains a heart-shaped islet of enamel.
Speaking the tooth
The type molar is fairly described as high-crowned (p.20); 7.3mm high to be precise. That compares to a crown length of 2.66 and width of 2.0. Rather than arising as a straight column, the molar distinctly curves along its course, first outwards and then back inwards. Further ornamentation is provided by a similarly curving furrow running up the lingual side of the tooth, and that's the feature which serves to render the flat dentine crown into something approaching a v-shape when seen from above. Opposing the interruption imposed by the furrow is the inverted heart-shaped enamel islet. About two-thirds of the walls of the tooth are enamelled, while the concave area's free of the stuff excepting for at the very top.
The extreme height, the flattened roof and the full length furrow are all badges proudly worn by gondwanatherians, and particularly sudamericids (p.21). (Ferugliotherium molars are brachyodont rather than hypsodont.) As with Lavanify, and in contrast to Gondwanatherium and Sudamerica, no transverse lophs occur on the crown, the furrow continues down into the root, and their sizes are also smaller. The prismatic structure of the enamel, and the enamel free area also unite this pair. Some contrasts between them could, at least in part, reflect vagaries such as degrees of wear and differing tooth positions (p.22), factors which the small sample sizes don't presently allow much exploration of. In any case, as Madagascar and India are thought to have still been in contact with each other at approximately 90 million years ago, faunal similarities from late during the Cretaceous are to be expected (p.23).
Some followers of fashion
The hypsodont molar became fashionable among some placental mammals as well, but not until much later during the Oligocene and Miocene. They turned out to be good for processing the spreading craze of grass. It all seemed to account for hypsodonts well enough, but then gondwanatherians turned up at just about the wrong sort of time and place. This outbreak of the fashion started off something like forty million years or so too early. While grasses weren't assumed to have been entirely absent, no signs of the stuff suggested they could only have been relatively sparse during the latter Cretaceous. An alternative explanation sought to pin the blame on soil laden roots or perhaps abrasive tree bark. Some digging mammals specialize in such trades today, and these include semi-aquatic exponents; most famously beavers. Another extant group, muroids, oblige by also possessing hypsodont molars with comparable microstructure of enamel, and the use of enamel-free zones (p.24). A hypothesis suggests a similar sort of lifestyle. However, as this conjecture can presently only be based upon dental characters, it can't fairly be termed totally convincing. Rather, it's a reasonable option among possible scenarios.
Given the presence of the new gondwanatherian in Indian, it's hardly surprising to find the authors citing very recent evidence of grass pollen found in the intertrappean beds of the Lameta Formation; at least five taxa have been identified in what appears to be fossilized dino dung. Perhaps, then, this bout of hypsodonty was also fuelled by grass. Perhaps, but lots of fossil pollen has been studied from other parts of the world, and evidence from elsewhere is even rarer than gondwanatherians. In fairness, I don't happen to know about the state of pollen studies at other gondwanatherian localities.
The latest Indian elections
Given the social problems, diversity and sheer size of India, many sensible and learned outsiders assumed that democracy couldn't work under such circumstances. This reasonable seeming conclusion is something most Indians failed to take into account. Across the lands of the Republic can be found governments ranging from dour conservative to flamboyant communist. Movie stars, priests and ex-bandits can all win elections.
However, that wasn't quite what I had in mind with the above subtitle. My interest here is more on the mounting early returns as the votes are being tallied in the intertrappean constituencies of Naskal, Rangapur and Kisalpuri. Not enough is yet known for confident announcements of outright victory, but it's starting to look like a massive landslide victory for the popularly called Northern Eutherian Front. Not even Mahatma Gandhi would've gained over 90% support. For one thing, I'm sure he wouldn't have voted for himself. At Kisalpuri, for example, the eutherians have around fifty votes and the entire Gondwanan Congress Party have mustered just one. This goes far beyond a bit of eutherian immigration. It's more like an overwhelming campaign of conquer. It's completely out of kilter with the (probably somewhat earlier) South American faunas involving Gondwanatherium. There's not a squeak of even a therian in the Campanian of Patagonia.
Reportedly, there is a eutherian presence in a mid-Maastrichtian aged fauna in Bolivia, but I've presently no details on that beyond: Gayet, M., L. G. Marshall, T. Sempere, F. J. Meunier, H. Capetta, and J.-C. Rage. 2001. Middle Maastrichtian vertebrates (fishes, amphibians, dinosaurs and other reptiles, mammals) from Pajcha Pata (Bolivia). Biostratigraphic, palaeoecologic and palaeobiogeographic implications. Palaeogeography, Palaeoclimatology, Palaeoecology 169, p.39–68. It would be better to compare the Indian faunas with other nearer Gondwanan localaties, but there's a persisting shortage aside from Madagascar.
VPL/JU/33 is a molar attending Jammu University. The specific name honours the emperor of Argentinean vertebrate paleontology, Dr Jose Bonaparte. He was the first to describe a gondwanatherian. To my shame, I've had to look up quite where Jammu is. The state and the city of that name are in northern India, with Kashmir further to the north.
|Reference:||Prasad et al (2007), A new Late Cretaceous gondwanatherian mammal from Central India, Proceedings of the Indian Natu. Sci. Acad, 73(1), p.17-24.|
Bonaparte JF, 1986|
Family: Ferugliotheriidae Bonaparte, 1986
Aka: Vucetichia Bonaparte, 1990
Remarks: Gondwanatheria is now generally not regarded as part of
Multituberculata but, according to
Kielan-Jaworowska & Hurum, 2001, (p.411): "a few specimens described as
?Ferugliotherium," are from multis. "These poorly known specimens (not
discussed herein) demonstrate that a branch of multituberculates apparently lived during the
Late Cretaceous in South America." As gondwanatherians aren't multis, these remains
would clearly not belong to this genus or grouping unless the genus happens to be a
multi of some strange kind!
|Species:||Ferugliotherium windhauseni Bonaparte JF, 1986|
|Aka:||Vucetichia gracilis Bonaparte, 1990|
|Place:||Los Alamitos Formation, Patagonia|
|Remarks:||The genus was established on the basis of a lower
molar, (m2), and provisionally referred to as a multi.
Further specimens were discovered, (m3 and M1), and other teeth were tentatively assigned;
incisors and premolars.
The upper premolars may be genuinely multituberculate, which explains their multi
The holotype, MACN-RN 20, is an inmate of the Museo de Ciencias Naturales, Buenos Aries. It's a lower molar (m2) with both a length and a width of 1.7mm, (Kielan-Jaworowska & Bonaparte, 1996). A cellmate is the holotype of Vucetichia, (MACN-RN 174). These were synonymized by Krause in 1993, (Krause & Bonaparte 1993, p.9379.)
In the view of Gurovich & Beck, 2008
|References:||Bonaparte (1986), Sobre Mesungulatum houssayi y nuevos mamíferos Cretácicos de Patagonia, Argentina. (Spanish, with English summary). Actas Congr. Argent. Paleontol. Bioestratigr. 4, p.48-61.|
|Bonaparte (1990), New Late Cretaceous mammals from the Los Alamitos Formation, northern Patagonia. National Geographic Research, 6, p.63-93.|
|Krause DW (1993), Vucetichia (Gondwanatheria) is a junior synonym of Ferugliotherium (Multituberculata). Journal of Paleontology 67, p.321-324.|
|Place:||Los Alamitos Formation, Patagonia|
|Remarks:||Update, November 2008|
Other authors have rebelled! Gurovich & Beck, 2008 have backed the original identification and transferred all the specimens back to Ferguliotherium. That should be held in mind while reading this episode.
The following is based upon my reading of Kielan-Jaworowska & Bonaparte, 1996, and it specifically concerns the material which was held to be from a multituberculate. (Thanks are due to Steve for sending the paper.)
The star of this paper is a fragment of dentary called MACN-RN 975. It's not very large but seemingly points to something significant; southern multis. As it was found in the same fossil beds as isolated teeth of the compatibly sized Ferugliotherium, it was questionably assigned to the same genus and species, (p.1). However, this fossil can't be placed in that taxon or even Gondwanatheria. The one preserved tooth on the piece of jaw is a long premolar (p4) with eight ridges and no cusp(s) on the buccal side. It's from a relatively derived, gondwanan multituberculate.
The fossil was found in 1991, (p.2). As well as the heavily worn tooth, the fragment also contains an alveolus for a relatively large incisor. A short diastema separates both teeth, but fracturing makes its length uncertain, (p.4). As the hole for the incisor continues along the whole length of the preserved fossil, the i1 must have been robust, (p.5). An i1 tentatively referred to Ferugliotherium would fit it well.
The premolar is 4.8 millimetres long, and that's a healthy size for Cretaceous multis (should it indeed come from a multi). Its external face shows eight faint ridges with at least that number on the lingual side as well. The lack of a buccal cusp is a relatively derived characteristic. This tooth has thin enamel, but that's probably due to processes of preservation rather than the natural condition. Both roots are strong, with the front one being larger than its rear colleague. As the premolar is relatively long and complex, (even though wear means its height can't be precisely determined), it isn't reminiscent of any multi premolars other than a p4. No known further anterior teeth have anywhere near eight ridges. Thus, despite the lack of an alveolus for a p3, a p4 is what it appears to be, (p.6). Presumably, this lineage had only a single premolar, as is the case for some later northerners.
The presence of only one premolar excludes this fossil from being a 'plagiaulacidan', as those animals had three to four of these teeth per side, (p.8). However, (and bearing in mind this was tentatively associated with remains of a different genus), affinities with the more advanced cimolodontans are not apparent. The find seems likely to represent an otherwise unknown southern radiation of multis, which could conceivably have arisen prior to the emergence of northern cimolodontans. The present lack of anything reasonably comparable inevitably results in little clarity. Clear is that the career of Multidom wasn't exclusively Laurasian.
Repetition for clarity: this fossil doesn't belong in Gondwanatheria.
|Reference:||Kielan-Jaworowska & Bonaparte (1996), Partial dentary of a multituberculate mammal from the Late Cretaceous of Argentina and its taxonomic implications, Revista del Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', New Series, 145, p.1-9.|
Bonaparte JF, 1986|
Family: Sudamericidae Scillato-Yané & Pascual, 1984
|Species:||Gondwanatherium patagonicum Bonaparte JF, 1986|
|Place:||Los Alamitos Formation, Patagonia|
Though earlier than Sudamerica, Gondwantherium is held to be more
derived. This may sound surprising, but there's no reason
why ancestral lines might not outlive descended ones.|
The genus was described on the basis of isolated, hypsodont, rodent-like molars. Originally, it was referred to the monotypic family of Gondwanatheriidae. Close similarities with Sudamerica were recognized, but the ridges of the enamel had a different pattern. Subsequently, further finds of Sudamerica teeth showed varying amounts of wear. This narrowed the differentiations and the genera were assigned to the same family by Bonaparte, (Krause & Bonaparte 1993, p.9379).
|Reference:||Bonaparte (1986), A new and unusual Late Cretaceous mammal from Patagonia, Journal of Vertebrate Paleontology, 6, p.264-270.|
|The affinities of Gondwanatheria|
The following is largely based upon my reading of Krause & Bonaparte, 1993.
In this study, gondwanatherians were referred to as members of a Superfamily,
(Gondwantherioidea), within Multituberculata. They
were held to be closer to 'Plagiaulacida',
(Plagiaulacoidea in the terminology employed), than the further
derived cimolodontans. This view didn't stand up in
the light of subsequent research, but the paper is still informative. Before making a case
for affinities with multis, the authors gave some details on apparent similarities with
|Genus: Lavanify Krause DW,
Prasad GVR, von Koenigswald W, Sahni A & Grine FE, 1997|
Family: Sudamericidae Scillato-Yané & Pascual, 1984
|Species:||Lavanify miolaka Krause DW et al, 1997|
|Place:||Maevarano Formation, Mahajanga Basin|
|Age:||Maastrichtian, Upper Cretaceous|
This genus is based a tooth, which was found whilst quarrying for
a dinosaur skull, (Majungatholus). A second specimen was also referred.|
"The teeth of Lavanify differ from those of the only previously known sudamericid genera Gondwanatherium and Sudamerica in possessing prominent and continuous inter(-)row sheets of interprismatic matrix in dental enamel and at least one cheek-tooth position that has a single, V-shaped dentine island and lacks enamel on one side of the crown. Lavanify further differs from Gondwanatherium in having cheek-teeth with vertical furrows that extend to the base of the crown and onto the root", (Krause et al, 1997, p.504).
|Reference:||Krause et al (1997), Cosmopolitanism among gondwanan Late Cretaceous mammals. Nature 390, p.504-507.|
Dino Land Paleontology Interviews, Dr Cathy Forster
Lavanify gets a brief mention in this interview. I particularly enjoyed the last line, her favourite moment in paleontology.
Scillato-Yané GJ & Pascual R, 1984|
|Species:||Sudamerica ameghinoi Scillato-Yané GJ & Pascual R, 1984|
|Place:||Punta Peligro, Patagonia|
In common with Gondwanatherium, this genus had high-crowned teeth, which are very
useful for eaters of grass. As there's still little evidence of grass in South America until later,
they may also have been effective for other food stuffs, (with thanks to Martin Jehle).|
Update: Research into Upper Cretaceous dino dung in 2005, suggests grasses are now known from the Upper Cretaceous of India, now also known Gondwnatherian territory. Caroline Strömberg of the Swedish Museum of Natural History and colleagues came across some pollen in samples from Central India.
"Pascual et. al. (1999) recently demonstrated the presence of four cheek-teeth, all of them molariform, in the dentary of the sudamericid Sudamerica, which is the only definitively identified gondwanatherian represented by a substantial jaw fragment", (Krause et al 2003, p.326). These authors also mention that the incisor of this critter had a root which extended underneath the entire length of the tooth row.
Gurovich & Beck, 2008 fully accept that dentary belongs to this genus and does have four molariform teeth. Furthermore (p.4), known isolated molariforms (both uppers and lowers) neatly divide into eight morphological groups. Both facts indicate that the molariform tooth count per adult jaw half was four. What these authors doubt are the strict molar identities of the first two molariforms. They suggest these could actually be molarized premolars.
A bit more on the molariforms
As mentioned by Kemp 2005 (p152-153), the presence of four molars and no premolar capable of shearing, aren't multituberculates characteristics. The molars have ridges running across the tops of them, and this effect is produced by wear. They probable worked well on tough plants of some kind. Of course, should Gurovich & Beck, 2008 be correct, then only two of the four teeth in question are strictly speaking molars.
The genus was originally based upon one hypsodont,
rodent-like molar, (Krause & Bonaparte 1993, p.9379).
|Reference:||Scillato-Yané & Pascual (1984), Un peculiar Paratheria, Edentata (Mammalia) del Paleoceno de Patagonia. Primeras Jornadas Argentinas de Paleonotologia de Vertebrados, Resumenes, p.15.|
Acta Palaeontologica Polonica, 44(3), p.263-300
Wighart v. Koenigswald, Francisco Goin, and Rosendo Pascual: Hypsodonty and enamel microstructure in the Paleocene gondwanatherian mammal Sudamerica ameghinoi.
Martin Jehle, Multituberculates: Heyday of the longest lived mammalian order
The last section of this overview of multis concerns Gondwanatheria.
Rougier et Al, 2009|
Family: Ferugliotheriidae Bonaparte, 1986
|Species:||Trapalcotherium matuastensis Rougier et Al, 2009|
|Place:||Allen Formation, Patagonia|
|Age:||Campanian-Maastrichtian, Upper Cretaceous|
|Remarks:||The following is based upon my reading of Rougier
et al, 2008. That's a prepublication version of the description which appeared in print
early in 2009, and the page numbering also differs. Thanks are due to the supplier.|
'Trapalco beast' is presently known from but a single tooth, but it does add some more meat to an already somewhat unclear stew. The authors uncontroversially enough refer it to the family of Ferugliotheriidae, and I envisage everybody will be happy enough with that. However, they then refer the family (with a question mark) to ?Multituberculata. What they don't discuss, presumably due to irrelevance in terms of their study, is the relationship of feruglios and sudamericids; both families of Gondwanatherians according to many. They make no comment about whether feruglios are or aren't also gondwans; a possibility should sudams also be ?multis. Another matte they look at is a purported ?cimolodontan multi (again, note the question mark) named Argentoides. They think it more likely to be material from a feruglio, a conclusion they share with Gurovich & Beck, 2008.
The tooth is a lower m1 molar with about half the buccal edge absent. The front of the occlusal surface is said to have "a more compressed" "anterior triangle" than Ferugliotherium. I think I know what that's referring to but I'm not certain. (My uncertainty may result from my lack of familiarity with papers on feruglios.) In any case, this genus differs by having this triangular feature in a more compressed form, and that applies whether my recognition is right or wrong! More clear to me is the presence of a crest curving along the front of the crown. Bases of cusps for this genus are less well developed, in that they've become more greatly merged into the crests running across the crown. Also, in this case, the buccal and lingual cusp rows differ more in terms of height.
In short, there are a number of distinctions from Ferugliotherium, thus a new genus was established.
Roughly the shape of things
The tooth is interpreted as a lower left molar. Reasons for this include the presence of only two cusp rows, the tooth being longer than wide, and the transversely running ridges as displayed by feruglios and sudamericids. One side has more cusps than the other and, as that's the buccal side, this identifies it as being a left molar. Whilst the rear of the buccal side is missing, the remains of transverse ridges suggest two further cusps were probably located there.
The crown outline is roughly rectangular in shape with the front, as mentioned, being curved somewhat like a bay window. Lingual cusps number three whereas there were probably five buccal ones, although four also can't be fully ruled out. In any event, buccal cusps were more numerous. Ridges link the cusps of both rows and furrows occur between those. There's a groove running between the cusp rows, but this gets blocked along its course by the ridges. The authors inform me: "The pattern of cusps, crests and furrows determines a mesial triangle pointing lingually and followed distally by two incompletely developed transverse ridges." As they go on to say, there's a triangular arrangement of the first two buccal and first lingual cusps (p.11), and I suppose you can base a triangle on those points well enough.
In short summary, this is a multituberculate-like lower molar in the sense that there are two rows of cusps, albeit cusps that can be difficult to see due to indistinctiveness, and a groove running between the rows, albeit somewhat eccentrically. Atypical for multis would be the lophs running across crown blocking that groove at various junctures.
The maximum length is 2.48mm and the greatest width manages 2.07. That's proportionately shorter and wider than Ferugliotherium windhauseni. However, I don't happen to know how may lower molars are known for that genus, and whether anything has been discovered with regards to possible distinctions between molar positions. (It's possible I've got some relevant information somewhere, so I'd better remember to check.) Such matters could be of relevance to comparisons.
Sudamericids aren't entirely ignored by this study. They're accused of being notable absentees in La Colonia Formation. While, given the minimalist sample size of mammal fossils from the Allen Formation, a lack of specimens from there has little significance as yet, over 300 mammalian specimens have been obtained from La Colonia. That lack of sudams is less likely to be merely some sampling blip. Preservation bias could be an explanation or, perhaps, sudams didn't find the paleo-environment there to their tastes.
Although a new source of mammals, this locality had already yielded a variety of other vertebrates; small and large sauropods, big bullying theropods, birds, hadrosaurs and ankylosaurs, snakes, sphenodont reptiles, turtles, frogs and several types of fish. This cast list also reflects themes played by the house orchestras of other Patagonian localities, which is none too surprising. Up north in Bolivia, the probably somewhat later El Molino Formation is also moving into the business of Mesozoic mammals, albeit presently unpublished ones. That fauna may include invading therians of northern ancestry. Unfortunately, that "may" must suffice until more and better specimens are available from there.
As much of South America was under water during the Upper Cretaceous, it would be interesting to know how more northerly faunas compared with Patagonian ones. Such comparisons would require new discoveries and then publications.
MML-Pv 16 is a lower molar (m1) in the collection of the Museum Municipal de Lamarque. The specific name pays homage to the important paleontological contributions selflessly made by the amateur researcher, Puesto El Matuasto. In professional life Matuasto performs valuable service as a shed. It's a herder's shed owned by the Cabazza family. The herd should also be thanked for agreeing to allow paleontologists to make use of their facilities, and this with a complete disregard for any offensive odours this might have resulted in.
|Reference:||Rougier GW, Chornogubsky L, Casadio S, Arango NP & Giallombardo A (2009), Mammals from the Allen Formation, Late Cretaceous, Argentina, Cretaceous Research, 30(1), p.223-238.|
Some unnamed material has been identified from the Deccan Traps.
NSF News, 3.12.1997
Strange South American Fossil Mammals Found in Madagascar and India.
Seymour Island, Antarctica
Antarctica apparently has more to offer than just marsupials.
"The occurrence on Seymour Island of sudamericids, that had become extinct in South
America in the Paleocene, also indicates that isolation may have allowed extended survival
of this Gondwanan group in the Eocene of Antarctica and the factors that caused their
extinction did not affect this continent," (Reguero et al 2002, p.189).
In case you thought I'd made a typing error, these photos show remains of marsupials from Antarctica.
|Specimen:||NMT 02067 Krause DW, Gottfried MD, O'Connor PM & Roberts EM, 2003|
|Place:||"Red Sandstone Group", Mbeya District|
The following is based upon my reading of Krause et al, 2003.|
The fist to state about this specimen is that the referral to Sudamericidae isn't simply tentative. It's very tentative, (p.321). In keeping with this spirit, the age of these particular sandstones is also poorly understood, (p.322).
The fossil in question is a partial lower jaw. It comes from deposits which probably represent the work of an ancient river system, (fluvial). The locality evidently took exception to having once been described as not rich in fossils, as it has since decided to yield an array of vertebrate remains: bony fish, crocs and the like, sauropod and theropod dinosaurs, a bit of bird leg and this jaw. Dino fossils have been found above, below and alongside the level where 02067 was found, so a pre-Paleocene age is a good bet. Taken as a whole, the faunal assemblage suggests Cretaceous, (p.323).
A jaw with teeth
This mammal fossil is a worn, left dentary but: "It lacks sufficient morphological information to allow the diagnosis of a new taxon." What can be said is that's it's short and deep and was home to one incisor and probably five single-rooted cheek teeth. None of these are now in Colgate-clean condition. The remains of the incisor show it was a large, forwardy-pointing tooth, with a root set at an angle of roughly 55° from the horizontal axis. This extends all the way back to below the front of the third cheek tooth.
Behind the incisor is a gap of a couple of millimetres or so, (a diastema). This is followed by remains of two cheek-teeth roots, the first of which suggests a slightly smaller chopper than the latter. The rest of the series are somewhat better preserved. Number three is clearly large and tall, and curves inwards to some extent. It's also well anchored, in that the root goes down to a depth of about 75% of the dentary, (p.324). The fourth in the sequence is similar in size to numbers 1 and 2, whilst the final member is the smallest tooth present. # These also have strong roots and all three hindmost teeth are "truly hypsodont", (p.325), which prompts me to search for a reliable translation; learning through googling.
('Hypsodont' literally translates as 'high tooth' -with thanks to Dental Anatomy of Horses. This page includes some interesting images, and the text is far from baffling; a fine bit of demystification from Colorado State University. And now back to p.325...)
Part the difficulty with this specimen is that it displays superficial similarities to a host or critters, and more diagnostic bits aren't preserved. It may be from an early representative of various taxa or evidence of a previously unknown one. However, amongst Mesozoic mammals, it shares the following series of characteristics with taeniolabidoidoid and djadochtatheroidean multituberculates and gondwanatherians: "body short and deep, unfused mandibular symphysis, distinct diastema and coronoid process originating far anteriorly". Those multi group are currently only known from the northern hemisphere, none are known to have hypsodont cheek teeth or more than two molariform teeth in each half of the lower jaw.
"We tentatively conclude that NMT 02067 is not a multituberculate and is most parsimoniously referred to the Gondwanatheria, and more specifically to the Sudamericidae (i.e., all gondwanatherians save Ferugliotherium)."
Whilst tantalizing, this find is also somewhat frustrating. It points to various interesting possibilities, but doesn't provide as much information as would be wished. However, any locality which contains one mammalian fossil very probably provides a refuge for more. Additional specimens would be most welcome. The jaw now lives in the collection of the National Museums of Tanzania, Dar Es Salam. It was discovered by Yasemin Tulu, (p.327).
|Reference:||Krause et al (2003), A Cretaceous mammal from Tanzania, Acta Palaeontologica Polonica, 48 (3), p.321-330.|
Acta Palaeontologica Polonica, 48(3), p.321-330
The full paper is freely available on-line.
Alvaro Mones home page
The on-line paleontologist and father of Gondwanatheria.
Should anybody have any further information, I'd be pleased to hear of it.
Regarding references and Bibliography:
With thanks to all the featured sources.
Trevor Dykes, April 2002. Latest up-date: 25.3.2009
|With further thanks due to:|
Martin Jehle, Genera and species of Paleocene mammals - Part 1
A useful source containing much basic info on names and locations.
BIOSIS, The Index to Organism Names
The Society of Vertebrate Paleontology BFV Online, (John Damuth)
Bonaparte JF (1990), New Late Cretaceous mammals from the Los Alamitos Formation, northern Patagonia, National Geographic Research, 6(1), p.63-93.
Gurovich Y (2005), Bio-Evolutionary aspects of Mesozoic Mammals: Description, phylogenetic relationships and evolution of the Gondwanatheria, (Late Cretaceous and Paleocene of Gondwana), Thesis, Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', Buenos Aires, 2005, pp.621.
Gurovich Y & Beck R(2008), The phylogenetic affinities of the enigmatic mammalian clade Gondwanatheria, Journal of mammalian evolution, prepublication copy (24 pages).
Kemp TS (2005), The Origin and Evolution of Mammals, Oxford University Press, pp.331.
Kielan-Jaworowska & Bonaparte (1996), Partial dentary of a multituberculate mammal from the Late Cretaceous of Argentina and its taxonomic implications, Revista del Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', New Series, 145, p.1-9.
Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and systematics of multituberculate mammals, Palaeontology, Vol 44 (3), p.389-429.
Kielan-Jaworowska Z, Ortiz-Jaureguizar E, Vieytes C, Pascual R & Goin FJ (2007), First ?cimolodontan multituberculate mammal from South America, Acta Palaeontologica Polonica, 52(2), p.257-262.
Krause DW & Bonaparte JF (1993), Superfamily Gondwanaterioidea: A previously unrecognized radiation of multituberculate mammals in South America, Proc. Natl. Acad. Sci. USA, 90, p.9379-9383.
Krause DW, Gottfried MD, O'Connor PM & Roberts EM (2003), A Cretaceous mammal from Tanzania, Acta Palaeontologica Polonica, 48 (3), p.321-330.
McKenna MC & Bell SK, (1997), Classification of Mammals Above the Species Level. Columbia University Press.
Prasad GVR, Verma O, Sahni A, Krause AW, Khosla A & Parmar V (2007), A new Late Cretaceous gondwanatherian mammal from Central India, Proceedings of the Indian Natu. Sci. Acad, 73(1), p.17-24.
Reguero MA, Sergio AM & Santillana SN (2002), Antarctic Peninsula and South America (Patagonia) Paleogene terrestrial faunas and environments: Biogeographic relationships. Palaeogeography- Palaeoclimatology-Palaeoecology, 179, p.189-210.
Rougier GW, Chornogubsky L, Casadio S, Arango NP & Giallombardo A (2008), Mammals from the Allen Formation, Late Cretaceous, Argentina, Cretaceous Research, prepublication copy (16 pages), officially published in 2009.