70 Paleontology, Biogeography/Biostratigraphy & Phylogenetic/Morphological Patterns (Posters)

Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

EVOLUTION OF THE MIOCENE PROTOLABINE CAMELS

Paper number: 70-1
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

The protolabines were a subfamily of North American camelids with distinctively long rostra pinched at the base between canine and P1. They have long been misunderstood, or mistaken for other taxa, and only been recognized as a discrete group in the last 50 years. They are distinctive not only in having a constriction of the rostrum, but also a strong buccinator fossa, lateral expansion of the anterior nares, and shortening of the metapodials. Although Honey and Taylor (1978) described new genera, there has been no complete review of the group since then. We recognize just three genera: Protolabis Cope, 1876; Michenia Frick and Taylor, 1971; and Tanymykter Honey and Taylor, 1978. Tanymykter was an early, extremely primitive protolabine that was long mistaken for Oxydactylus. It contains two species, the late Arikareean T. brachydontus, and the larger early Hemingfordian taxon T. longirostris. Protolabis now contains just four species: the primitive Hemingfordian taxon P. saxeus; the type species from the early Barstovian, P. heterodontus (including P. barstowensis and “P. browni”); the highly derived Clarendonian-Hemphillian taxon P. coartatus; and the Clarendonian-Hemphillian P. yavapaiensis.  Finally, the much smaller and more derived genus Michenia is known from several species, including the late Arikareean M. agatensis and M. cameloides (= M. deschutesensis), early Hemingfordian M. exilis, and the late Hemingfordian-Barstovian M. mudhillsensis. Thus, the tribe Protolabidini originated in the late Arikareean, diversified rapidly in the Hemingfordian and reached its maximum diversity in the Barstovian, then declined to just two genera and two species in the Clarendonian and early Hemphillian.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412345

© Copyright 2025 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.