Palaxius caucaensis n. sp., a Crustacean Microcoprolite from the Basal Nogales Formation (Campanian to Maastrichtian) of Colombia

Crustacean microcoprolites from Jurassic (Oxfordian) hydrocarbon-seep deposits of Beauvoisin, southeastern France

“…The five ichnospecies of Palaxius differ in arrangement and orientation of concave or convex sides of the canals relative to the symmetry plan. These differences are discussed in detail by Senowbari-Daryan and Silantiev (1991) and Blau et al (1995).…”

“…Remarks: Apart from P. salataensis, four other ichnospecies with four canals within the ichnogenus Palaxius exist (cf., Senowbari-Daryan and Kube 2003): P. tetraochaetarius Palik (1965), P. kumaensis Senowbari-Daryan and Silantiev (1991), P. montemeranoensis Blau and Grü n (1989), and P. caucaensis Blau, Moreno and Senff (1995). The five ichnospecies of Palaxius differ in arrangement and orientation of concave or convex sides of the canals relative to the symmetry plan.…”

Early Cretaceous crustacean microcoprolites from Sierra de la Cara Cura, Neuquén Basin, Argentina: Taphonomy, environmental distribution, and stratigraphic correlation

“…In addition to the preservation problem there is a biological problem involved in the generation of these trace fossils, including: a) that the same ichnotaxon can be produced by different producers of different size (Blau and Grün, 1989;Blau et al, 1995); and b) there is a differentiation in the gut development of crustaceans during ontogenesis, and a differential evolutionary rate between the decapod morphology and their digestive system (Schweigert et al, 1997). Therefore, it has been observed that species with a lower number of canals have longer biochrons, whereas species with greater number of canals have shorter biochrons.…”

“…Reports of crustacean microcoprolites in South America are relatively scarce, consisting in a few species from Peru, Colombia, Venezuela and Chile (Förster and Hillebrandt, 1984;SenowbariDaryan and Stanley, 1986;Blau et al, 1994Blau et al, , 1995De Romero and Galea-Álvarez, 1995). The first record of crustacean microcoprolites from the Neuquén Basin was reported by Kietzmann and Palma (2010a).…”

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a b s t r a c tA new Early Cretaceous association of crustacean microcoprolites from the southern Mendoza sector of the Neuquén Basin, includes Palaxius salataensis Brönnimann, Cros and Zaninetti, 1972; Palaxius caucaensis Blau, Moreno and Senff, 1995; and Favreina cf. F. belandoi Fels, 1997.

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