Catopithecus
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Catopithecus Temporal range: Late Eocene |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Haplorrhini |
| Parvorder: | Catarrhini |
| Superfamily: | †Propliopithecoidea |
| Family: | †Oligopithecidae |
| Genus: |
†Catopithecus Simmons, 1989 |
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Catopithecus is an early catarrhine fossil. It is known from more than 16 specimens of a single species, Catopithecus browni, found in the Jebel Qatrani Formation of the Fayum Province, Egypt. The Jebel Qatrani Formation has been divided into two main faunal zones based on the fact that the fauna found in the lower portion of the quarry appear to be more primitive that fauna found in the upper section of the quarry. The upper zone has been dated to older than 31 ± 1 myr based on the dating of a basalt layer that lies immediately above the formation and Nicolas Steno’s Law of Superposition. The lower zone contains the late Eocene green shale unit called Locality-41 (L-41) in which all the specimens of Catopithecus browni have been found. The relative dating of L-41 based on paleomagnetic correlations places it at 36 Myr. This date indicates that Catopithecus lived during the Eocene epoch, making Catopithecus the earliest known anthropoid.
From the Greek “cato” meaning “below” and “pithekos” meaning “one who plays tricks” (an ape), therefore Catopithecus means “below (before) ape.” The species name, browni, is form the discoverer of the type specimen, Mark Brown.
The type specimen of C. browni, CGM 41885, is a right mandible discovered in 1987 by Mark Brown. The mandible was found with intact molars 1-3, and premolars 3-4, and alveoli are present for a canine tooth and incisors 1-2, indicating a lower dental formula of 2.1.2.3. This dental formula was demonstrated to reflect the upper (maxillary) dental formula in specimen DPC 8701 which was discovered in L-41 in 1988. At least 17 specimens, including six almost intact skulls, have been described and are listed below:
Skulls: DPC 8701, CGM 42222, DPC 11388, DPC 11594, DPC 12367, and CGM 41900 Mandibles and other fragments: DPC 7339, 7340, 7341, 7342, 8772, 9869, 11434, 11541, 11638, and DPC 11943
Analyses of the skull specimens show that C. browni had post orbital closure developed to the degree seen in extant anthropoids. The orbit to skull size ratio of the C. browni skulls were compared to ratios of modern nocturnal and diurnal anthropoids in Rasmussen and Simmons (1992) and demonstrated that C. browni was most likely diurnal. The interorbital distance of the skulls was also compared to five taxa of modern primates in Rasmussen and Simons (1992), and demonstrated that C. browni had an interorbital distance range comparing it most closely to those of modern prosimians and callitrichids.
In contrast to extant anthropoids that express a fused mandibular symphysis, the mandibular symphysis of C. browni was observed to be unfused but covered in small rugose features in at least seven specimens.
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