The monotremes of Home-Earth form a small group of Australasian oddballs, a trio of species (the platypus and two echidnas) that are unique among living mammals in their retention of many primitive features, the most famous of which is reproduction though egg-laying. They are popularly, if somewhat erroneously, portrayed as “living-fossils”, curiosities from some bygone era that have only survived by living in some biogeographical backwater where “time stood still”.

The situation on the Specworld could not be more different. Here, the monotremes are vastly more diverse, vastly more widespread and have attained a fair greater size than their HE counterparts. They swim through the desert sands of the Ozspec outback while their haunting calls can be heard across the frigid Antarctic coast. They have taken to the oceans and become the largest mammals that Spec has ever seen. Phylogenically, they may be the basalmost of living furballs, but they are also some of the most highly specialized creatures on the planet.

The presence of hindlimb-spurs (which may or may not be envenomed) and egglaying , our home time-line's exclusive halmarks of Monotremata, are not reliable identifiers on Specworld as they exist in several other mammal groups.  To make matters worse, several lineages of Spec-monotremes give live birth, some groups even going so far as to evolve a placental system on par with eutherians. Monotremes can still be easily distinguished in possessing leathery bills that are packed with electrosensors, the absence of nipples and the possesion of a single cloaca rather than separate external excretory and reproductive vents. Notable skeletal features include the presence of an interclavicle, paired coracoids and poorly coiled cochlea in their inner ears. As far as is known, all monotremes lack incisors and canines.

The early history of the monotremes is very poorly understood - the only Mesozoic fossil remains we have are collections of  jaws and teeth from the Aptian-Albian of Australia that  suggest an already considerable degree of diversity and specialization at this early date. While their disposition at the end of the Cretaceous remains unknown, a brief comparison between the monotreme faunas of the two timelines strongly suggests that K-T extinction must have hit these furry egg-layers very hard indeed. In the early Cenozoic of Home-Earth, the monotremes were a very minor component of the outer Gondwanan fauna and soon became restricted to a handful of Australian relicts. On Spec, the monotremes have gone from strength to strength and, while generally not competing directly with other mammals in terrestrial niches, have gone on to produce a host of weird and wonderful forms.
 

ORNITHORHYNCHOIDEA (Bunyips, platypuses, and fangbills)

The ornithorhynchoids are a possibly paraphyletic collection of terrestrial and freshwater monotremes that can broadly described as “platypus-like” forms and includes true platypuses (Ornithorhynchidae). These are low-slung, flattened quadrupeds with duck-like bills, five-toed limbs and a well-developed tail. Well developed venom-spurs are present in one or both sexes. Most species lay eggs, but a few have taken to ovoviviparity, particularly those that live in colder climates. Ornithorhynchoids have highly distinctive teeth that lack many key features of more derived mammal clades (such as entoconids).  

OVILESTIDAE (Bunyips)

The Australian bunyip is the sole representative of this family. It is an edentulous, largely terrestrial egg-laying form that is unique amongst the ornithorhynchoids in walking with an erect leg-stance, giving it considerable overland agility. The spine has become strengthened and less flexible and has lost the reptilian side-to-side motion of its relatives. It seems likely, based on their vertical swimming-motion, that the ancestors of the cancridonts went through a similar revolution in posture leading to suggestions of a relationship between the two. Biochemical studies and the morphology of ovilestid baby-teeth have produced little evidence to support this theory, however.

The bunyip is a terrestrial platypus found in well vegetated habitats throughout much of Australia. Although generally found near water, the bunyip is largely terrestrial in its habits.  This badger-like creature roots in the leaf-litter for fungi, insects and reptiles. They are also notorious egg-thieves, opportunistically seizing the eggs and young of ground-nesting birds and small dinosaurs.

Female bunyips have well-developed pouches with which to carry it’s single offspring.

 

 

ORNITHORHYNCHIDAE (Platypuses and fangbills)

“Typical” platypuses, ornithorhynchids have a wide bill that lack any tooth-like projections. Teeth may be present or absent with up to 2 premolars and 3 molars on each jaw (a maximum of 2 molars on the upper jaw).  Ornithorhynchids are the most widely distributed platypuses and are found throughout Australasia and New Caledonia.

PSEUDODONTORHYNCHIDAE (Fangbills)

The so called “fangbills” are odd-looking creatures restricted to Australia and New Guinea. At first glance, these creatures appear to have large, pointed incisor and canine teeth. A closer examination reveals these “teeth” to be keratinous spikes that sit on bony outgrowths of the enlarged premaxilla.  In addition to the “fangs”, these are the only monotremes to possess whiskers, with a cluster of tactile hairs present at the base of the bill. The real teeth are particularly large and well-developed, and they differ from ornithorhynchids in having 3 upper molars. Most fangbills lose their venom-spurs at adolescence; when you’ve got such a powerful set of choppers, you don’t need spurs.

Pseudodontorhyncids tend to go after vertebrate prey more often than their cousins, requiring the use of the stabbing false-teeth.  Many species are also quite aggressive and can pose a hazard to human spexplorers. Trying to wrench one’s foot from the jaws of an angry powerpus is not an experience quickly forgotten.

 This brutish creature can grow up to 1.5 metres in length and is found near fresh and estuarine waters in temperate southeastern Australia including Tasmania and the Bass Strait Islands. It has webbed feet and swims well but spends a great deal of time on land where, it walks with a rather awkward-looking semi-erect gait that masks its ability to produce sudden bursts of speed.

 

 

 

 

The powerpus is the scourge of waterfowl and is famous grabbing it’s hapless victim’s foot from beneath the surface. The high number of one-footed ichthybirds seen hobbling about in some areas is a sure sign that the local waters are infested with powerpuses. It will also attack birds on land, usually ambushing its prey from some concealing vegetation. Any nest that draws the attentions of a powerpus results in the quick demise of eggs and hatchlings. Turtles, frogs and even snakes are also known to be consumed by this ravenous beastie.

In early summer, when the lakes of Ozspec bloom with algae and botulism sweeps through the waterfowl population, powerpusses enjoy the year's greatest feast.  The loud and flatulent *POFF!* *POFF!* made by the montoremes as they puncture the bloating bodies of the helpless and dying birds is one of the most macabre sounds of Ozspec.

The powerpus is an extremely aggressive, short-tempered critter, particularly during nesting time. It has a nasty habit of constructing its burrow near well-used thoroughfares and will quickly latch on to any poor spexplorer’s leg that should come crashing through the roof.

A rare, little-known creature about the size of a large rat,  known from northern Australia (conforming to HE Kakadu and Arnhem Land) and the Trans-Fly region of southern New Guinea. The longnosed fangbill is immediately recognizable by its elongated bill, pointed false-fangs and prominent conical cusps on its teeth. Also striking is the lack of webbing on  its rather small forefeet.
 

 

The longnosed fangbill dwells in overgrown reed and lilybeds, using its dextrous, webless hands to clamber through dense aquatic vegetation. Its diet appears to consist primarily of amphibians (especially tadpoles) and small fish.

The peculiar, mouse-sized frog-shrew is a member of the fangbill group of toothed platypi and lives in the fast flowing tropical forest streams of far north Queensland and Papua, feeding on the small invertebrates that hide among the rocks. Despite the long hind legs and huge span of its frog like feet, the frog-shrew does not kick as its principal means of swimming. Instead, like other fangbills, the frog-shrew undulatesits body up and down, stretching its legs out backwards, sticking its feet out slightly to act as paddles, but keeping most of the webbing folded up. This means of locomotion has prompted many biologists to wonder why the frog-shrew evolved its hyper-developed hind limbs in the first place, since they do not aid in swimming and, indeed, are often down-right detrimental as they induce drag and increased heat-loss through their surface area.

 

 

 

 

(fig. 4) Frog-shrew, Ranotalpa minutus (Eastern Australia and Papua )

 

The frog-shrew's hind limbs, however, are useful for providing short bursts of speed; the frog-shrew is an ambush-predator, and its webbed feet allow it to dart out from behind rocks and weeds to snatch passing insects and small vertebrates.   The webs are also useful in the evasion of predators, which the frog-shrew may escape simply by deploying its webs and catching the current, sending it sailing several meters downstream in a matter of seconds.  Frog-shrews often evade predatory fish and dinosaurs in this manner, though craftier marsupial often hunt frog-shrews in pairs, one carnivore waiting downstream to catch the fleeing monotreme. 

 

Due to their low monotreme metabolism, frog-shrews, even when swimming with webs tightly folded against their sides, cool quickly when swimming and must emerge periodically to bask on rocks.  When basking, the frog-shrew will spread its hind legs and deploy its webs to their fullest extent warming its blood and raising its body temperature back to normal before returning to the water. 

 

 

 

 

 

 

(fig. 6) Detail of hind legs and webs of frog-shrew

Odd as the inflated monotreme diversity of Spec's Australia is, the handful of Ozspec's platypus-like species is nothing compaired to the staggering diveristy and outright strangness of the other great monotreme branch, Cancridontia.

CANCRIDONTIA (Smoochers and Walduks)

Brian Choo, Tim Morris, Clayton Bell, and Daniel Bensen

                                    ,=Ovilestidae=Ovilestes furs (Bunyip)