Rodents (Talk.Origins)

Response Article

This article (Rodents (Talk.Origins)) is a rebuttal regarding a supposed transitional form published by the Talk.Origins Archive under the title Transitional Vertebrate Fossils FAQ.

Response to Rodents

CreationWiki response: (Talk.Origins quotes in blue)

General rodents

• Anagale, Barunlestes, or a similar anagalid (mid-late Paleocene) -- A recently discovered order of primitive rodent/lagomorph ancestors from Asia. Rabbit-like lower cheek teeth, with cusps in a pattern that finally explains where the rabbits' central cusp came from (it's the old anagalid protocone). Primitive skeleton not yet specialized for leaping, with unfused leg bones, but has a rabbit-like heel. No gap yet in the teeth. These fossils have just been found in the last decade, and are still being described and analyzed. Barunlestes in particular (known so far from just one specimen) has both rodent-like and rabbit-like features, and may be ancestral to both the rodents and the lagomorphs. This lineage then apparently split into two groups, a eurymyloid/rodent-like group and a mymotonid/rabbit-like group.

This entire description is vague and filled with evolutionary assumptions with no hint of even attempted objectivity. Traits are refer to as rodent like and rabbit like with out any details. Despite being classified as different in families it is still possible that they are varieties of the same kind of animal. The fact that these animals are classified based only on skeletons and incomplete ones at that, makes the likely hood the same kind of animal would be classified as more than one family even greater.

• Heomys (mid-late Paleocene, China) -- An early rodent-like eurymyloid. Similar overall to Barunlestes but with added rodent/lagomorph features (enamel only on front of incisors, loss of canines and some premolars, long tooth gap) plus various rodent-like facial features and rodent-like cheek teeth. Probably a "cousin" to the rodents, though Chuankuei-Li et al (1987, and in Szalay et al. 1993) think it is "very close to the ancestral stem of the order Rodentia."

The similarities with Barunlestes suggest that Heomy and Barunlestes are both the same kind of animal. The fact that the both Heomy and Barunlestes are classified as from the mid-late Palaeocene strengthens this possibility. Besides Heomys is not actually considered an ancestor so all it proves is that this kind of animal had some rodent and rabbit like traits. Since Anagale, Barunlestes and Heomys are classified as from the mid-late Paleocene they would all be contemporaries with no objective order. They were simply places in the order most favorable to evolution.

• News flash Tribosphenomys minutus (late Paleocene, 55 Ma) -- A just-announced discovery; it's a small Asian anagalid known from a single jaw found in some fossilized dung. ....
• Acritoparamys (was "Paramys") atavus (late Paleocene) -- First known primitive rodent.
• Paramys & its ischyromyid friends (late Paleocene) -- Generalized early rodents; a mostly squirrel-like skeleton but without the arboreal adaptations. Had a primitive jaw musculature (which modern squirrels still retain). Rodent-like gnawing incisors, but cheek teeth still rooted (unlike modern rodents) and primitive rodent dental formula.

First off all three of these are dates as late Paleocene, making them contemporaries and making the order arbitrary, so once again they are the order on this list is 100% evolutionary assumptions.

• Tribosphenomys minutusin known from just a single jaw.
• Acritoparamys was once classified as Paramys suggesting that they are the same kind of animal. Also Paramys' skeleton is described as mostly squirrel like suggesting that it was a variety of squirrel.

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What we have here are two kind of animals possible a third in two contemporary sets are by Evolutionary dating methods. Thus the order is that each set is arbitrary and based on only Evolutionary assumptions.

Squirrels:

Paramys (see above) Protosciurus (early Oligocene) An early squirrel with very primitive dentition and jaw muscles, but with the unique ear structure of modern squirrels. Fully arboreal.

Paramys is classified as late Paleocene and Protosciurus is classified as early Oligocene, so where is the Eocene? Besides both Paramys and Protosciurus are clearly varieties of squirrel.

Sciurus, the modern squirrel genus. Arose in the Miocene and has not changed since then. Among the rodents, squirrels may be considered "living fossils".

These are modern squirrels

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All we have here is evidence of variation among the squirrel kind, no evidence of macro evolution.

Beavers:

Paramys (see above) Paleocastor (Oligocene) -- Early beaver. A burrower, not yet aquatic. From here the beaver lineage became increasingly aquatic. Modern beavers appear in the Pleistocene.

Paramys is classified as late Paleocene and Paleocastor is classified as Oligocene, so where is the Eocene? Thus there is no real evidence of a relationship between Paramys and Paleocastor. Talk Origins claims a transition to modern beavers but it is unsubstantiated. No intermediate fossils are presented so that the claim can be evaluated. The implication is that there are no intermediate fossils between Paleocastor and Beavers so the claim seems to be based purely on the evolutionary assumption that Beavers evolved from Paleocastor. All though there are vague similarities between Beavers and Paleocastor, they do not seem to be related. In the absence intermediate fossils there is no real evidence for a relationship between Beavers and Paleocastor.

Rats/mice/voles:

Paramys (see above) Eomyids -- later Eocene rodents with a few tooth and eyesocket features that show they had branched off from the squirrel line.

Paramys is classified as late Paleocene and Eomyids is classified as later Eocene, so where is the early and mid Eocene? Thus there is no real evidence of a relationship between Paramys and Paleocastor.

All are indications that Eomyids seems to be a rodent with a few squirrel like traits in it teeth and eye socket. This does not prove any connection to Paramys or other squirrels, such similarities are not unexpected, particularly when people are looking for any similarity that can be claimed as evidence of decent. Further more the decription is some what vage and sounds rather subjective.

Geomyoids -- primitive rodents that have those same tooth & eyesocket features, and still have squirrel-like jaws; Known to have given rise to the mouse family only because we have intermediate fossil forms.

Given the similarites between these Geomyoids sugests that they arre the same kind of animal, though ironicaly it jaw seems to have been more squirrel like than that of Eomyids. Furthermore Talk Origins conventely leaves out the fact that like Eomyids these Geomyoids are date to the later Eocene making them contempararies.

Talk Origins claims to have intermediate fossil forms between these Geomyoids and mise but they list no type or anything else that could be used to check out their claim. The most they would show is that these Geomyoids are varieties of mouse, which would not be to surprizing since madern mice and rates are clasified as Geomyoids. It has already been shown that the created kinds do occasionaly extend to the order level so even if a clear connection can be shown it would still fit the creation model.

In the Oligocene these early mice started to split into modern families such as kangaroo rats and pocket gophers. The first really mouse- like rodent, Antemus, first appeared in the Miocene (16 Ma) in Asia. In the Plio-Pleistocene, modern mice, hamsters, and voles appeared and started speciating all over the place. Carroll (1988, p. 493) has a nightmarish diagram of vole speciation which I will not try to describe here! The fossil record is very good for these recent rodents, and many examples of species-species transitions are known, very often crossing genus lines (see below).

Most of this is nothing but 100% evolutionary interpretations without any objective substance. Since the created kinds most often extend to family level, these cross genus " transitions" are not a problem for created kinds.

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With the possible exception of Paramys all of the types on this list may be the same created kind. But this is assuming that Talk Origins' unsubstantiated claims are accurate. The most this shows it that rats, mice and voles are the same created kind.

Cavies:

GAP: No cavy fossils are known between Paramys and the late Oligocene, when cavies suddenly appear in modern form in both Africa and South America. However, there are possible cavy ancestors (franimorphs) in the early Oligocene of Texas, from which they could have rafted to South America and Africa.

All they have here is a gap. This one is a joke. Evolutionsits have absoluty nothing here, even by their standards.

Known species-species transitions in rodents:

Chaline & Laurin (1986) show gradual change in Plio-Pleistocene water voles, with gradual speciations documented in every step in the following lineage: Mimomys occitanus to M. stehlini to M. polonicus to M. pliocaenicus to M. ostramosensis. ... Lundelius et al. (1987) summarizes and reviews species-species transitions in numerous voles, grasshopper mice, jumping mice, ... Ex: Sigmodon medius to Sigmodon minor, and Zapus sandersi to Zapus hudsonius. ... Goodwin (in Martin, 1993) describes gradual transitions in prairie dogs, with Cinomys niobrarius increasing in size and splitting into two descendants, C. leucurus and C. parvidens. Kurten (1968) describes a transition in voles, from Lagurus pannonicus to L. lagurus. Rensberger (1981) describes a likely lineage in the development of hypsodonty (high-crowned teeth for eating grass), among seven species of meniscomyine rodents in the genus Niglarodon. Vianey-Liaud (1972) showed gradual change in two independent lineages of the mid-Oligocene rodent genus Theridomys.

• Not presented in the order presented at Talk Origins.

These are cases of species within the same genus, as such it is not a problem for created kinds.

In a previous paper, Chaline (1983, p. 83) surveyed speciation in the known arvicolid rodents. About 25% of the species have fossil records complete enough to study the mode of appearance. .. Fahlbusch (1983) documents gradual change in various Miocene rodent transitions. Martin (1993) summarizes and reviews the numerous known Pleistocene rodent species-to-species transitions in muskrats, water voles, grasshopper mice, prairie voles, pocket gophers, and cotton rats. Michaux (in Chaline, 1983) summarized speciations in mice. He found a wide variety of modes of speciation, ranging from sudden appearance to gradual change. Vianey-Liaud & Hartenberger (in Chaline, 1983) also describe gradual shifts in size and shape in Eocene rodents (mainly theridomyids), concluding that gradual evolution explains their data better than punctuated equilibrium.

• Not presented in the order presented at Talk Origins.

These descriptions are too vague for analysis, however there is nothing that presents any difficulty for the concept of created kinds.

Jaeger (in Chaline, 1983) describes gradual shifts in tooth size and shape two genera of early mice, related to the development of grazing. Stuart (1982, described by Barnosky, 1987) showed smooth transitions in water voles, including a genus transition. Mimomys savini gradually lost its distinctive tooth characters, including rooted cheek teeth, as it changed into a new genus, Arvicola cantiana, which in turn smoothly changed into the modern A. terrestris.

• Not presented in the order presented at Talk Origins.

Since created kinds most often extend to at least the family level, this is to be expected.

Chevret et al. (1993) describe the transition from mouse teeth to vole teeth (6-4.5 Ma).

• Not presented in the order presented at Talk Origins.

This is vague, but it simply sugests that mise and voles are the created kind.

Conclusion:

Once again, we see vast variety with distinct kinds of animals. The supposed relationships with others kinds are highly questionable. The differences between many of these "links" are too great to supposed any real relationship. There are cases where Talk Origins has just placed types that are dated as contemporaries in the order that favors evolution and there are also significant gaps in theoretical time that Talk Origins makes no mention of. As is typical this list is based more the the assumption of Evolution than on reality.

See Also

• Transitional forms