terça-feira, setembro 03, 2013

Os crustáceos do Mesozóico de Portugal

Nem só de dinossauros vive o Homem... e amiúde aparecem uns quantos invertebrados interessantes. Por isso, juntamente com Carlos Neto de Carvalho, do Geopark Naturtejo da Meseta Meridional e Adiël Klompmaker, da Universidade da Florida, fizemos a resenha do que se conhece se crustáceos do Jurássico e Cretácico de Portugal, que foi apresentada no congresso da especialidade "5th Symposium on Mesozoic and Cenozoic Decapod Crustaceans".

Glyphea sp., um dos crustáceos semelhante a lagosta, do Jurássico Superior de Portugal.
Mateus, O., Neto de Carvalho C., & Klompmaker A. A. (2013). Decapod crustacean body and ichnofossils from the Mesozoic of Portugal. 5th Symposium on Mesozoic and Cenozoic Decapod Crustaceans. , 25–27 June 2013, Warszawa: Polish Geological Institute − National Research Institute & AGH University of Science and Technology
PDF aqui.

The decapod crustaceans body fossils from the Mesozoic of Portugal are restricted to the Oxfordian-Kimmeridgian and Lower Cretaceous deposits from the Lusitanian Basin. At least the following genera are known: Longodromites, Pithonoton, Eodromites, Magila, Meyeria, Mecochirus, and Glyphea. Wehner (1988: p. 132) listed three crabs from the mid-Oxfordian Cabaços Formation? (Torres Vedras): the longodromitid Longodromites excisus (von Meyer, 1857), and goniodromitid including Pithonoton marginatum (von Meyer, 1842) and Eodromites grandis (von Meyer, 1857). The axiid shrimp Magila sp. was reported by Werner (1986) from the Thracia-Corbulomima assemblage (Early Kimmeridgian) at Consolação (Peniche municipality). Three lobster genera are known: Mecochirus Germar, 1827 (Mecochiridae) is reported from the Kimmeridgian Alcobaça Formation at Barrio (F.T. Fürsich, 1999 in http://paleodb.org); Meyeria rapax (Harbourt, 1905) is known from the Barremian Boca do Chapim Formation (Neto de Carvalho et al., 2007); and Glyphea von Meyer, 1835 (Glypheidae) is here documented from Kimmeridgian sediments from Praia dos Salgados (collected by OM, 2000). In these specimens (FCT-UNL 703; fig. 1), the branchiocardiac and postcervical grooves are similar to Glyphea spp. as in Amati et al. (2004), Feldmann and Maxwell (1999), and Feldmann and De Saint Laurent (2002). Additionally, several indeterminate decapods from the Kimmeridgian of São Martinho do Porto are reported here (collected by OM, 2000).
Besides body fossils, the Mesozoic of Portugal has yielded several ichnotaxa produced by crustaceans including burrows and fecal pellets (or microcoprolites). Fürsich (1981) recognized the presence of several ichnotaxa in the Late Jurassic of the Lusitanian Basin, namely: Diplocraterion habichi (Lisson, 1904), D. parallelum Torell, 1870 (both perhaps produced by shrimp), Ophiomorpha isp. (?shrimp), Psilonichnus tubiformis Fürsich, 1981 (crab), Rhizocorallium irregulare Mayer, 1954 (?crustacean), and Thalassinoides suevicus (Rieth, 1932) (lobster). All represent burrow structures. Neto de Carvalho et al. (2010) unequivocally showed that the lobster Meyeria rapax was the producer of the burrow Thalassinoides suevicus and provided an overview of Lower Jurassic–Upper Cretaceous ichnofossils from Portugal (Lusitanian Basin) and added the crustacean burrows Asterosoma ludwigae Schlirf, 2000, (?decapod, see also Neto de Carvalho and Rodrigues, 2007) Macanopsis plataniformis Muñiz and Mayoral, 2001 (crab), and Rhizocorallium jenense Zenker, 1836 (?crustacean). The oldest burrows are known from the Sinemurian extending to the Cenomanian (Rhizocorallium and Thalassinoides). In addition to burrows, crustacean microcoprolites are also known. Ramalho (1971) recognized Favreina cf. F. salevensis (later identified as Favreina guinchoensis Brönniman, 1976) from the Late Jurassic, and also found some Favreina coprolites from the Valanginian of Portugal. Leinfelder in Schweigert et al. (1997) reported on the microcoprolites Petalina hexalunulata Leinfelder, 1997 and Favreina prusensis (Paréjas, 1948) from the Kimmeridgian Ota Limestone. Favreina is known from the Sinemurian to the base of the Valanginian in Portugal.
Decapod trace fossils are preserved commonly in environments where body fossils may be found, but are usually rare. Therefore, a combined study involving both body and trace fossils provide a more thorough assessment of the evolutionary and biogeographic history of decapods.

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