Youngoides minor RC91- better data

For decades the only published view of the RC91 specimen of Youngoides minor (Broom and Robinson 1948, Late Permian) was their published drawing (Fig. 1).

Figure 1. Youngoides minor RC91 by Broom and Robinson 1924.

Figure 1. Youngoides minor RC91 by Broom and Robinson 1924.

This is a pretty good reconstruction for the fossil, which is broken lengthwise between the dorsal and ventral portions (Fig. 2, images courtesy of Bruce Rubidge).

Figure 2. Youngoides minor RC91 in dorsal and ventral views. Yes, the left side is folded on itself.

Figure 2. Youngoides minor RC91 in dorsal and ventral views. Yes, the left side is folded on itself.

Given these two images, you might think they were two different fossils, but actually the ventral portion is folded back at right angles beneath the dorsal portion.

Figure 3. Youngoides minor RC91 digitally colorized.

Figure 3. Youngoides minor RC91 digitally colorized.

Here (Fig. 3) DGS helps identify the various bits and pieces.

Figure 4. Youngoides minor RC91 reconstructed.

Figure 4. Youngoides minor RC91 reconstructed.

A reconstruction (Fig. 4) puts it all together. The phylogenetic placement did not change with the additional data.

Lower and wider than other specimens named Youngoides, RC91 was derived from a sister to the RC90 specimen of Youngina and was basal to the AMNH 5561 specimen of Youngina. The skull of the RC91 specimen of Youngoides minor has slightly constricted rostrum in dorsal view. The jawline is convex. The orbit enters the anterior half of the skull. The supratemporal and postorbital contact and the posterior jugal descends. It is among the smallest specimens. And, yes, that is a nascent antorbital fenestra.

References
Broom R and Robinson JT 1948. Some new fossil reptiles from the Karroo beds of South Africa: Proceedings of the Zoological Society of London, series B, v. 118, p. 392-407.

wiki/Youngina

RC = Rubidge Collection, Wellwood, Graaff Reinet, South Africa.

 

 

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