Two zebus with traits of the Indian aurochs

At first glance, zebus seem to be rather different from the aurochs. But there are certain traits found in many zebus that are very reminiscent of the wildtype. For example, many zebu landraces from South Asia have a very short trunk with long legs (more so than most taurine breeds on this world) and small udders. Many also have a comparably long snout. Surely, their often hanging ears, the fleshy hump (which is less likely to be a wildtype trait than a trait that appeared after domestication) and the often rather derived horn shapes give them an unusual appearance that creates the impression they are more removed from the aurochs than taurine breeds, but the huge udders, the piebald colour and tiny horns of Holstein-Frisian, for example, are not wildtype traits either. And not to forget, zebus have been found to share alleles with the European aurochs that taurine cattle have lost [1]. It is most parsimonious to assume that these alleles were also present in the Indian aurochs. Thus, zebus are actually more "primitive" than their looks suggest at first glance. 

While searching for zebus with wildtype traits I found photos of one living zebu and one skull that both respectively share traits with Bos primigenius namadicus. 

For the living individual, go here and here. It has a crazily extreme primigenius spiral. And as so often when a domestic cattle individual has a perfect primigenius spiral, it is a steer (the picture description on shutterstock says it is an ox, thus castrated). Nevertheless, the horns are interesting. Not only because of their curvature, but also because they are antero-posteriorly compressed on the proximal half and thus oval in cross section, which was a trait of B. p. namadicus. In the African aurochs, B. p. mauretanicus, and also some European aurochs, B. p. primigenius (particularly those from the Pleistocene), we see the opposite, namely dorsoventrally compressed horns at the base. Thus, the horns of this zebu steer resemble the Indian aurochs in this respect, thus they can be considered "primitive". I would love to see the bony horn cores of this individual, to see if they have keels. A bony keel on the dorsal and ventral ridge of the horn core was a trait of Indian aurochs, particularly in early individuals [2], that later was lost in zebus again. Whether or not these keels were visible in the living animals is unknown, as no keratinous horn sheaths of this subspecies have been preserved. Therefore it would be interesting to see the bony horn cores of that steer. 

The zebu skull that is interesting can be seen here and here. What makes the skull interesting is that it can be seen that the forehead is slightly convex, which is a trait inherited from B. p. namadicus and the opposite of what is seen in the other aurochs subspecies and taurine cattle (a planar or slightly concave forehead). Also, the profile of the snout is completely straight, while European aurochs and taurine cattle have a slightly convex bulge at the base of the snout. The profile of the zebu skull, and that of many other zebus, thus resembles that of wild B. p. namadicus in these two respects: 

The skull of the Indian aurochs in profile view is at the bottom right; a cross section of the horn with the keels can be seen at fig. 6

Too bad that there is no complete skeleton of the Indian aurochs available. Plentiful of remains of B. p. namadicus have been found, but always only fragmentary specimen consisting of few elements and never a complete skeleton. My suggestion would be to create a composite skeleton in order to get a more complete picture of the morphology of this aurochs subspecies by taking well-preserved remains of individuals of the same sex and size and create a (more or less) complete skeleton. The same has been done for the neanderthal, from which no complete skeleton is known either.  

Literature 

[1] Orlando et al.: The first aurochs genome reveals the breeding history of British and European cattle. 2015. 

[2] Bökönyi: Zebus and Indian wild cattle. 1997.