Is the Equidae a holobaramin?
Paul Garner (Biblical Creation Ministries)
The bottom line:
Members of the horse family seem to belong to a single created kind, but it is not yet clear whether horses can be distinguished from all non-horses. This study used statistical baraminology to investigate this question, but the data were too poor to draw definitive conclusions.
Restoration of Eurohippus parvulus, an extinct horse from the Eocene Grube Messel, on display in the Museum für Naturkunde, Berlin, Germany. Photo courtesy Haplochromis (Wikipedia).
Horses are well-represented in the fossil record, especially in North America, and appear to form a convincing, though complex, phylogenetic sequence. This sequence has been cited as important evidence in support of evolutionary theory, while creationists have attempted to debunk it as artificial and composed of non-equivalent parts. The status of Hyracotherium as the ancestral horse has been particularly controversial in the creationist literature.
Cavanaugh et al. (2003) presented a statistical baraminology study and concluded that nineteen fossil equids – including Hyracotherium – belonged to a single monobaramin. However, their analysis did not include a non-equid outgroup and was thus unable to detect any discontinuity surrounding the equids.
This study involved a baraminic distance correlation (BDC) analysis of a morphological dataset obtained from Hooker (1994), comprising 35 characters for 13 fossil taxa. The taxa included both equid and non-equid perissodactyls and phenacodontid condylarths. The analysis revealed four clusters of taxa united by significant positive correlation: (1) Cymbalophus cuniculus + ‘Hyracotherium’ sandrae ; (2) Phenacodus + Ectocion ; (3) Cardiolophus + Hallensia louisi + Pachynolophus hookeri ; (4) Hyracotherium leporinum + Propachynolophus gaudryi + ‘Propachynolophus’ maldani. This group in turn appears to correlate with Pliolophus pernix + Pliolophus vulpiceps. However, overall there was poor negative correlation between the clusters. The exception is the significant negative correlation between the phenacodonts and the remaining taxa – consistent with their status as outgroup taxa.
The major limitation of this study is that all the included characters are dental, so the dataset is not holistic. For this reason, strong conclusions could not be drawn and the question of whether the Equidae is a holobaramin remained unresolved.
The results of this study were presented at the 2004 Biology Study Group conference (Garner 2004). An analysis based on a new dataset of 72 characters and 26 taxa was carried out in 2016.
Cavanaugh, D.P., T.C. Wood and K.P. Wise. 2003. Fossil Equidae: a monobaraminic, stratomorphic series, pp.143-153 in Ivey, R.L. (ed.), Proceedings of the Fifth International Conference on Creationism. Creation Science Fellowship, Pittsburgh, Pennsylvania.
Garner, P. 2004. Is the Equidae a holobaramin? p.10 in Sanders, R. (ed.), Discovering the Creator: Proceedings of the Third BSG Conference, Occasional Papers of the BSG 4.
Hooker, J.J. 1994. The beginning of the equoid radiation. Zoological Journal of the Linnean Society 112:29-63.