Contributions to Zoology, 72 (2-3) 187-189 (2003) SPB Academic Publishing bv, The Hague Early Cretaceous arthropods from plattenkalk facies in Mexico 5, Francisco+J. Vega P. Garcia-Barrera M. Coutiño T. Nyborg P. Cifuentes-Ruiz¹,K. González-Rodríguez ¹, ², ³, 4 6, 7 ³ A. Martens C.R. Delgado & G. Carbot 1 2 Institute) de Geologia, UNAM, Ciudad Universitaria, Coyoacdn, Mexico D. F. 04510, Mexico; Facultad de 3 Ciencias, UNAM, Ciudad Universitaria, Coyoacdn, Mexico D. F. 04510, Mexico: Museo de Paleontologia, Instituto de Natural Calzada de los Hombres Ilustres Tuxtla Historia y Ecologia, s/n, Gutierrez, Chiapas 4 29000, Mexico; Department ofNatural Sciences, Loma Linda University, Loma Linda, CA 92350, USA; 5 Museo de Paleontologia, Centro de Investigaciones Bioldgicas, Universidad Autonoma del Estado de Hi- 6 a dalgo, Km 4.5 Carretera Pachuca-Tulancingo, C.P. 42184Pachuca, Hidalgo, Mexico; Zwarteweg 76 NL- , 1 2511 VV Den Haag, the Netherlands; Departamento de Paleontologia, SEPC-MUDE. Prol. Perez Trevinn 3745, Parque Las Maravillas, C.P. 25015, Saltillo, Coahuila, Mexico Keywords: : Cretaceous, plattenkalk, Arthropoda, Mexico that ofthe Abstract portant to note most brachyuran remains while represent molts, none of the numerous Several well-preserved arthropod faunas have been studied in isopods appear to be. Morphology of the isopod Mexico the past few The of the present during years. purpose species resembles modern fish parasites. It seems note is to outline advances in the study ofthese arthropods and fish probable these isopods and were associated, of their paleoenvironmental implications, from four localities. both getting trapped in the freshwater environment The for these localities from the the Late age ranges Early to a particular (storm) event. Recent isotopic Cretaceous. At most of these localities lithographic limestones during have revealed that the crop out, with fish remains representing the most attractive ele- studies Tepexi lithographic ment of study. However, arthropods constitute a impor- very limestone was deposited in a freshwater environ- tant tool for reconstructing paleoenvironment(marine crustaceans, ment, with periodic marine influence, and that a freshwater and terrestrial insects and arachnids). Detailed stu- reef was proximal to this marginal environment of dies these assemblages will aid in our understandingofancient et ah, 2002). coastal dynamics and the paleoecology ofthese unique envi- (Guerrero-Arenas ronments. Zimapán, Hidalgo Tepexi de Rodríguez, Puebla Muhi the Trancas For- The Cerro quarry exposes This locality is famous for the exceptionally well- mation of laminar limestone, of probable Cenoma- preserved diverse and reef fish fauna (Applegate, nian age, with foraminifera, ammonites, crinoids, 1995). The diversity here is remarkable; on record echinoids, and a diverse ichthyofauna (Gonzalez- are reptilian remains (lizard, turtle, crocodile, pte- Rodriguez, 2002; Gonzalez-Rodriguez and Apple- Sev- rosaur), foraminifera, sponges, corals, ammonites, gate, 2000; Gonzalez-Rodriguez et ah, 2000). belemnites, gastropods, bivalves, holothurians, as- eral mecochirid specimens are under study. One teroids, ophiuroids, echinoid ossicles, and even a specimen is provisionally assigned to Linuparus. fungus (Applegate, 1987). A middle to late Albian Due to its relatively recent discovery, the Muhi has been for the red lime- has furnished limited mate- age suggested lithographic quarry comparatively stone of the Tlayiia Formation (Seiberz and Buitron, rial so far. 1987). Arthropods are represented by an unidenti- fied insect wing, a dragonfly nymph, one species °f arachnid, one species of isopod, and two spe- cies of decapods (Feldmann et ah, 1998). It is im- Downloaded from Brill.com10/01/2021 06:03:14AM via free access - 188 F.J. Vega et al. Mexican Early Cretaceous arthropods Rincón Colorado, Coahuila been identified. A single, almost complete molt of Palinurus has also been collected, as well as a pair This locality is famous for its abundantand diverse of pagurid chelae. Finally, a well-preserved speci- dinosaur remains. Coprolites, tortoise bones, fresh- men of odonate nymph is part of the assemblage. fruits and it that is water gastropods, bivalves, angiosperm However, appears only one group present of leaves are abundantat certain horizons (Rodriguez- at each horizon. Although the presence diag- de la Rosa and Cevallos-Ferriz, 1994; 1995; 1998). nostic terrestrial and freshwater elements clearly A complete specimen and an isolated leg of a blattoid suggests a freshwater/brackish water environment, (cockroach), a small spider (Salticidae?) of less than the abundance and good preservation of tanaidaceans and of have more marine conditions. Tanaidaceans I mm, a partial wing dragonfly re- suggest are sensitive environmental cently been collected from clay beds of the early very to changes, especially Maastrichtian when concentrations fluctuate. is Cerro del Pueblo Formation. Diverse oxygen It impor- and tant to note that the and Palinurus palm other angiosperm leaves were found within pagurid are rep- A the same layer. more detailed study of these resented by molts, but the state of preservation of arthropods will contribute to the paleoecological the molt of the first is remarkable, suggesting little setting providing a unique opportunity to look at or no transport at all. Although arthropod material the association of arthropods and an abundant di- seems to be enough to complete the first formal nosaur fauna at this locality in NE Mexico. contribution for this locality, more work is needed in order to define the of this paleoenvironment new, and potentially diverse, locality in southern Mexico. El Espinal, Chiapas A series of quarries exposing laminated dolomite, Conclusions located northwest ofTuxtla Gutierrez, Chiapas, has It produced vegetable matter, a few gastropods, small seems that the Aptian/Albian-Cenomanian was bivalves, and a rare fish fauna(Gonzalez-Rodriguez an important time interval in Mexico, with the depo- et ak, 2002; Ovalles and Alvarado, 2002). A late sit of several mixed environments along the east- Albian is for this of the of the fossils Aptian-early age suggested part ern part territory. Study preserved of the Sierra Madre Formation, based on lateral at these localities allows a unique opportunity to biostratigraphic correlation (Michaud, 1987). Fos- describe these mixed marine, freshwater and ter- siliferous limestone of the upper unit of the Sierra restrial elements, of which only the arthropods are Madre Formation contains the foraminifer Num- represented as a group across all three. Unfortu- moloculina of Albian-Cenomanian the of finds in lime- heimi, age (Steele nately, frequency lithographic and Locals have the the of Waite, 1985). exploited quar- stone quarries depends directly on intensity ries and thus of and of is also de- informally, no complete exposure work, preservation specimens the section has been studied. The becalne of the in of the quarry pendent educating people charge of interest to local paleontologists on account of quarry. From the above-mentioned localities, only its fossil fish yield. However, their remains seem Tepexi de Rodriguez has been supported institu- to be in other localities. This in order this national scarce comparison to tionally to preserve inherit- be due less intensive the ance. We know how may to working at quarry. may never many important No microfossils have been found, except for a few specimens have been destroyed or sold through ostracode remains. the abundanceof tanai- The to However, ignorance or by necessity. only way protect daceans is remarkable. Horizons with hundreds of these treasures is to bring them to light, and hope specimens could be followed laterally, suggesting that people will understandtheir scientific value to mass mortality events. A single species of tanai- our and future generations. dacean is and reconstruction recognized, is pos- sible based on some well-preserved specimens. Other horizons contain isopods, ofwhich two species have Downloaded from Brill.com10/01/2021 06:03:14AM via free access Contributions to Zoology, 72 (2-3) - 2003 189 References Nuevos datos de la paleoambientales Cantera Tlayiia en Tepexi de Rodriguez, Puebla, Mexico. XVI Convention Geologica National. Libro de Resumenes, Puerto Vallarta. Applegate SP. 1987. 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