T269 The Geology of Colombia (Posters)

Wednesday, 7 November 2018
9:00 AM - 6:30 PM
Halls J-K

PALEOBIOGEOGRAPHIC AFFINITIES, BIOSTRATIGRAPHIC POTENTIAL, AND TAXONOMY OF CRETACEOUS TEREBRATULIDE BRACHIOPODS FROM COLOMBIA

Paper number: T269-4
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Published records of Cretaceous brachiopods from Colombia date back to the mid-nineteenth century. However, since then their formal description and discussion in the literature has been sporadic. We present a genus-level inventory/review of Early and middle Cretaceous terebratulide brachiopods from Colombia in particular in relation to their paleobiogeographic affinities and biostratigraphic significance and potential. The taxa identified are known to occur elsewhere and no endemic faunal elements at the genus-level, or higher taxonomic rank have yet to be recognized.

The paleobiogeographic affinities of Colombian Cretaceous terebratulides are primarily transatlantic, Circum-Atlantic, and cosmopolitan. Among the “short-looped” terebratulidines recorded from Colombia Sellithyris is a cosmopolitan form; Musculina and Hadrosia can be considered transatlantic as they are also recorded from Europe. We have measured a suite of 10 external morphological characters that help distinguish Colombian Sellithyris from Mexican and European representatives.

“Long-looped” terebratellidines from Colombia include Colinella, Arenaciarula, and Gemmarcula. Colinella is known from Mexico and Europe, the latter two genera being originally described from Europe. The widely distributed genus Psilothyris, known from the USA, Mexico, Argentina, and Europe, has yet to be recorded from Colombia.

Where detailed locality and stratigraphic information is available, brachiopods may provide some local-basin correlation, such as “event-horizon” type occurrences, where brachiopod concentrations (“brachiopod beds”) due to local or basin-wide events and/or ecological conditions.

The scarcity of records of rhynchonellide brachiopods in the Cretaceous of Colombia is intriguing. Rhynchonellide genera such as Cyclothyris and Ptilorhynchia are represented in contemporaneous Cretaceous faunas containing terebratulides, for example, South America, Mexico, and Europe. However, to date, these associations have not been identified among Colombian Cretaceous brachiopod faunas.

The opening Central Atlantic acted as a conduit for brachiopod dispersal during the Early and middle Cretaceous. By the Late Cretaceous the widening Atlantic Ocean is becoming a barrier to dispersal.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-325121

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