Mexican Kossmatia — Historical review and revision proposal.

Well-adapted to high-standard science at the time, Carl Burckhardt made a relevant contribution to stratigraphy in Mexico, providing the guidelines for subsequent research. A revision of his pervasive influence focuses in the interpretation of the ammonite genus Kossmatia Uhlig, with reference to Burckhardt's interpretations between 1906 and 1930, and to those made by subsequent authors. The historical revision of interpretations made at the species- and genus-level reveals a rather "blind follow-up" of Burckhardt's biostratigraphy during the majority of the 20th century. The resulting slowing-down in knowledge was forced by the common discontinuity in ammonite records, unfavorable preservation, relative rarity of ammonite-rich horizons, endemism, and especially by sampling procedures and unnoticed clues in Burckhardt's papers that would have served as guidelines to drive a more appropriate progress. Only since the nineties of 20 th century, interpretations of Mexican Kossmatia benefited from application of horizon-biostratigraphy, and complementary information derived from calpionellids. Aside from mere morphologic grounds, precise biostratigraphy and the favored paleobiogeographic model dynamics support the formal proposal of two new taxa of genus level to replace the use of the taxon-name Kossmatia for Mexican ammonites. The new taxa Burckhardtieia and Aguilerites are endemic and inconclusively known because of selective preservation favoring phragmocones against body-chambers. The new taxonomic proposal helps to identify a local fauna that distributed across the southern north-American plate during middle-to-late Early Tithonian (two-fold division) to Lower and early-Middle Berriasian times, while its origin can only be tentatively interpreted at present. • Carl Burckhardt (1912) first used Kossmatia for Latest Jurassic ammonites in Mexico. • Gaps in ammonite records, preservation, and sampling, hampered fine biostratigraphy. • Horizon-biostratigraphy as the tipping-point for revisions in the past nineties. • Updated revision of Kossmatia literature precludes its application in Mexico. • Bidding two new Mexican taxa fits revisions of Kossmatia literature, recent data, and updated interpretations. [ABSTRACT FROM AUTHOR]