BRACHIOPODA OCCURRING IN THE GULF OF MEXICO 



By G. ARTHUR Cooper, Curator, Invertebrate Paleontology and Paleobotany, V. S. National Museum 



Brachiopods are rare or uncommon animals 

 in most parts of the modern world. They occur 

 in abundance in a few places only, such as off 

 southern Australia, New Zealand, and parts of 

 Japan. They occur in lesser variety in the northern 

 Atlantic, the Arctic, Antarctic, and Mediterranean. 

 They are thus worldwide in distribution. Although 

 rare at the present time, brachiopods were abun- 

 dant in the past. Paleozoic seas abounded in 

 brachiopods, but in the Mesozoic era, although 

 numerous, they began to lose ground to the 

 MoUusca. Furthermore, in the Mesozoic era 

 their family representation became reduced; this 

 was the great time for the Rhynchonellacea and 

 was the time of upsurge of the Terebratulacea, 

 or looped forms. 



Following the Mesozoic era, Tertiary time saw 

 a further reduction of brachiopods as the MoUusca 

 continued to e.xpand. Tertiary brachiopods are 

 generall}^ not abundant, but areas where they are 

 common are New Zealand, southern Australia, 

 and Japan. Thej' are also fau-ly common in the 

 Mediterranean and West Indies regions. It is 

 interesting to note that these areas of abundance 

 correspond closely with modern distribution. 

 Recent brachiopods are similar to Tertiary ones, 

 and their roots can be satisfactorily traced into 

 the Tertiary and on into the Mesozoic in several 

 instances. 



The brachiopods found so far in the Gulf of 

 Mexico are mostly types inlierited from the 

 Tertiary of the Middle Atlantic and West Indian 

 regions. The latter mfluence is very strong, and 

 most of the Gulf species are the same as those 

 occurring in the waters around the West Indies. 

 These Gulf species are Glottidia pyramidafa 

 (Stimpson), Crania pourfalesii Dall, Cryptopora 

 gnomon Jeffreys, Chlidonophora incerta (David- 

 son), Terebratulina cailleti Crosse, Gryphus cu- 

 bensis (Pourtalcs), G. bartschi Cooper, G. bart- 

 lettii (Dall), Argyrotheca barrettiana (Davidson), 

 A. lutea (Dall), A. schrammi (Crosse and Fischer), 

 Dallina floridana (Pourtales). 



The species recorded from the Gulf, except for 

 Glottidia, occur in West Indian waters. , A num- 

 ber of brachiopods that have West Indian 

 affinities are also known from the south side of 

 the Florida Keys. Both of these areas have 

 yielded species not yet recorded from Gulf waters, 

 but any of these species may yet be found in the 

 Gulf with more intensive searching. These are 

 Thecidellina barretti (Davidson) 1866, Eucalathis 

 n. sp., Platidia seminula (Philippi) 1836, and 

 Pantellaria echinata (Fischer and Oehlert) . 



The information recorded in this paper was 

 derived from the records published by W. H. Dall 

 supplemented by data with specimens in the 

 national collection of Recent brachiopods. Dall's 

 Annotated List of the Recent Brachiopods in the 

 Collection of the United States National Museum, 

 with Description of Thirty-three New Forms 

 gives data for most occurrences up to 1920. 

 Unfortunately, several of the Gulf species in the 

 national collections have no bathymetric data, 

 and several have no geographic information other 

 than their origin in the Gulf. I am Indebted to 

 Dr. Harry B. Wliittington, Harvard University, 

 for additional data on Gulf brachiopods in the 

 collections of the Museum of Comparative 

 Zoology, Harvard University. 



Glottidea pyramidata (Stimpson) 



Lingula pyramidata Stimpson. Am. Jour. Sci., ser. 2, 

 vol. 29, 1860, p. 444. 



This species has the characteristic form of the 

 familiar Lingula, but it is small, about 15 milli- 

 meters long and has a pale yellow or light brown 

 color. It has been taken from Tampa Bay, 

 Cedar Keys, and Marco on the Gulf coast of 

 Florida. The specimens from Marco are from 1 

 to 3 fathoms. Like Lingula, this genus is a 

 shallow-water dweller. 



Crania pourtalesii Dall 



Crania anomala var. pourtalesii Dall. Bull. Mas. 

 Comp. Zool., Harvard, vol. 3, 1871, p. 35, pi. 1, figs. 

 7a-b. 



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