Species-to-species transitions in the fossil record

A claim repeated endlessly by those seeking to deny evolution is the supposed absence of transitional forms or intermediates. There are at least two ways such a claim could be intended: no fine-scale, species-to-species transitions, or no larger-scale transitions from one group to another group. I refute the former claim here on this page, and the latter claim on a related page. Initially, I will give a couple of detailed examples of species-to-species transitions documented in the literature, and follow that with a lengthy table giving many more examples. The long table is a list that I have assembled from some haphazard checking in the literature, so it is very far from comprehensive, being concentrated in mammals, and a bit in molluscs, since those two groups happened to be ones presented in the books and journal articles that I examined. But, it does give one a feeling for how many putative examples are in the literature of species-to-species transitions.

Perhaps the best refutation of the claim of no fine-scale transitions is Dr. Phil Gingerich's publication in American Journal of Science in 1976, showing a smooth transition among several early small rodents in the genus Hyopsodus. In the diagram below, from his 1976 paper, the horizontal axis is a measure of dental morphology, and the vertical axis is time, with the top being most recent. The short horizontal lines within the graph show the range of dental morphologies found in fossils from different age strata at the study site. This diagram shows Hyopsodus loomisi giving rise to a number of eventual descendant species, with several intermediates existing along the way. Similar diagrams can be shown for a variety of other mammals, most particularly horses. The obvious conclusion is that there is no basis whatsoever for the claim that fine-scale transitions are absent from the fossil record. But, to drive the point home more forcefully, I present the list below.

Let's be sure we're clear about what is presented here. Those who reject evolution will point out that these examples are not proven, and that is 100% correct. Indeed, PROOF would be exceedingly difficult. What is given here are examples in which relevant experts concluded that Species A gave rise to Species B; and that the fossils were of the right age, morphology, and location for this ancestor-descendent scenario to be probable. These are NOT presented as proof that the ancestor surely DID give rise to the descendent, but as proposed relationships. This is in response to the widespread and erroneous claim by ID proponents that there are few or no species-to-species transitions in the fossil record. We will examine the large-scale transitionals on a different web page.

I present animals only here, not because I think plants are unimportant, but because so much of the discussion of evolution by the ID community is centered on animals. Indeed, the ID proponents seem to have forgotten that plants exist at all.

This table is just getting put together and is far from complete; the rest of the examples will come as soon as I can type them in -- working with the HTML is very tedious.

ClassOrderAncestor DescendantReference
Bivalvia Pelecypoda Babinka oelandensis Babinka prima Pojeta 1975
Bivalvia Pelecypoda Fordilla troyensis Actinodonta secunda Pojeta 1975
Bivalvia Pelecypoda Fordilla troyensis Babinka oelandensis Pojeta 1975
Bivalvia Pelecypoda Fordilla troyensis Lyrodesma armoricana Pojeta 1975
Bivalvia Pelecypoda Fordilla troyensis Redonia prisca Pojeta 1975
Bivalvia Pelecypoda Lyrodesma armoricana Lyrodesma conradi Pojeta 1975
Bivalvia Pelecypoda Lyrodesma conradi Lyrodesma poststriatum Pojeta 1975
Bivalvia Pelecypoda Modiolopsis davyi Modiolopsis modiolaris Pojeta 1975
Bivalvia Pelecypoda Modiolopsis davyi Modiolopsis oviformis Pojeta 1975
Bivalvia Pelecypoda Redonia prisca Redonia bohemica Pojeta 1975
Cephalopoda Ammonita Collignoniceras praecox Prionocyclus hyattiKennedy et al. 2001
Cephalopoda Ammonita Collignoniceras woollgari Subprionocyclus neptuni Harada & Tanabe 2005
Cephalopoda Ammonita Collignoniceras woollgari Collignoniceras praecox Kennedy et al. 2001
Cephalopoda Ammonita Subprionocyclus neptuni Subprionocyclus minimus Harada & Tanabe 2005
Cephalopoda Ammonita Subprionocyclus neptuni Subprionocyclus normalis Harada & Tanabe 2005
Mammalia Artiodactyla Alces gallicus Alces latifrons Kurten 1968
Mammalia Artiodactyla Antilocapra garciae Antilocapra americana Kurten & Anderson 1980
Mammalia Artiodactyla Bison crassicornis Bison bison Kurten 1968
Mammalia Artiodactyla Bos planifrons Bos namadicus Kurten 1968
Mammalia Artiodactyla Dama clactoniana Dama dama Kurten 1968
Mammalia Artiodactyla Eucladoceros falconeri Eucladoceros sedgwicki Kurten 1968
Mammalia Artiodactyla Mylohyus floridanus Mylohyus nasutus Kinsey 1974
Mammalia Artiodactyla Myotragus bateae Myotragus balearicus Kurten 1968
Mammalia Artiodactyla Odocoileus brachyodontus Odocoileus virginianus Oelrich 1953
Mammalia Artiodactyla Ovis mivicola Ovis dalli Kurten & Anderson 1980
Mammalia Artiodactyla Platygonus bicalcaratus Platygonus compressus Kurten & Anderson 1980
Mammalia Artiodactyla Platygonus pearcei Platygonus vetus Woodburne 1968
Mammalia Artiodactyla Sus minor Sus strozzii Kurten 1968
Mammalia Carnivora Acinonyx studeri Acinonyx trumani Kurten & Anderson 1980
Mammalia Carnivora Bassariscus casei Bassariscus astutus Kurten & Anderson 1980
Mammalia Carnivora Borophagus direptor Borophagus diversidens Kurten & Anderson 1980
Mammalia Carnivora Buisnictis schoffi Buisnictis breviramus Kurten & Anderson 1980
Mammalia Carnivora Canis arnensis Canis etruscus Kurten & Anderson 1980
Mammalia Carnivora Canis davisi Canis lepophagus Kurten & Anderson 1980
Mammalia Carnivora Canis etruscus Canis lupus Kurten & Anderson 1980
Mammalia Carnivora Canis lepophagus Canis latrans Kurten & Anderson 1980
Mammalia Carnivora Canis lepophagus Canis priscolatrans Kurten & Anderson 1980
Mammalia Carnivora Canis lupus Canis familiaris Kurten & Anderson 1980
Mammalia Carnivora Canis priscolatrans Canis rufus Kurten & Anderson 1980
Mammalia Carnivora Crocuta sivalensis Crocuta crocuta Kurten 1968
Mammalia Carnivora Cuon priscus Cuon alpinus Kurten & Anderson 1980
Mammalia Carnivora Felis lunensis Felis sylvestris Kurten 1968
Mammalia Carnivora Gulo schlosseri Gulo gulo Kurten & Anderson 1980
Mammalia Carnivora Lutra licenti Lutra canadensis Kurten & Anderson 1980
Mammalia Carnivora Lynx issiodorensis Lynx canadensis Kurten & Anderson 1980
Mammalia Carnivora Lynx issiodorensis Lynx lynx Kurten & Anderson 1980
Mammalia Carnivora Martes paleosinensis Martes diluviana Kurten & Anderson 1980
Mammalia Carnivora Martes vetus Martes martes Kurten 1968
Mammalia Carnivora Mustela stromeri Mustela eversmanni Kurten & Anderson 1980
Mammalia Carnivora Osteoborus cyonoides Borophagus direptor Kurten & Anderson 1980
Mammalia Carnivora Panthera augusta Panthera onca Seymour 1993
Mammalia Carnivora Pliotaxidea nevadensis Taxidea taxus Kurten & Anderson 1980
Mammalia Carnivora Procyon rexroadensis Procyon lotor Kurten & Anderson 1980
Mammalia Carnivora Smilodon gracilis Smilodon fatalis Seymour 1993
Mammalia Carnivora Sminthosinus bowleri Grisonella cuja Kurten & Anderson 1980
Mammalia Carnivora Spilogale rexroadi Spilogale putorius Kurten & Anderson 1980
Mammalia Carnivora Trigonictis cookii Galicis vittata Kurten & Anderson 1980
Mammalia Carnivora Urocyon progressus Urocyon cinereoargenteus Kurten & Anderson 1980
Mammalia Carnivora Ursavus elmensis Protursus simpsoni Kurten 1976
Mammalia Carnivora Ursus arctos Ursus maritimus Kurten 1976
Mammalia Carnivora Ursus deningeri Ursus spelaeus Kurten 1976
Mammalia Carnivora Ursus etruscus Ursus americanus Kurten 1976
Mammalia Carnivora Ursus etruscus Ursus thibetanus Kurten 1976
Mammalia Carnivora Ursus etruscus Ursus savini Kurten 1976
Mammalia Carnivora Ursus etruscus Ursus arctos Kurten 1976
Mammalia Carnivora Ursus minimus Ursus etruscus Kurten 1976
Mammalia Carnivora Ursus savini Ursus deningeri Kurten 1976
Mammalia Carnivora Vulpes alopecoides Vulpes vulpes Kurten & Anderson 1980

Literature Cited

Gingerich, P.D. 1976. Paleontology and phylogeny – patterns of evolution at species level in early Tertiary mammals. American Journal of Science 276: 1-28.

Hulbert, R.C. 1993. Taxonomic evolution in North American Neogene horses (subfamily Equinae): the rise and fall of an adaptive radiation. Paleobiology 19: 216-234.

Kurten, B. 1968. Pleistocene mammals of Europe. Aldine Pub. Co., Chicago, IL.

Kurten, B. 1976. The Cave Bear Story: Life and Death of a Vanished Animal. Columbia University Press, New York.

Kurten, B., and Anderson. 1980. Pleistocene mammals of North America. Columbia University Press, New York.

MacFadden, B.J. 1985. Patterns of phylogeny and rates of evolution in fossil horses: hipparions from the Miocene and Pliocene of North America. Paleobiology 11: 245-257.

MacFadden, B.J., and R.C. Hulbert. 1988. Explosive speciation at the base of the adaptive radiation of Miocene grazing horses. Nature 336: 466-468.

Shoshani, J., and P. Tassy, eds. 1996. The Proboscidea: evolution and palaeoecology of elephants and their relatives. Oxford University Press, Oxford, UK.

Werdelin, L., and N. Solounias. 1991. The Hyaenidae: Taxonomy, systematics and evolution. Fossils & Strata 30: 1-104.

This is incomplete: stay tuned for the rest of the detailed bibliography.