espanolLos peces Pycnodontiformes son un grupo muy conocido, presente en numerosas colecciones de todo el mundo. Se les conoce entre el Triasico Superior y el Eoceno, y algunos generos tienen una amplia distribucion a escala mundial. Han sido muy estudiados en los dos ultimos siglos, pero la mayoria de los trabajos tratan sobre taxonomia, siendo raros los que versan sobre paleobiologia. En este articulo se presenta un metodo que relaciona la longitud estandar con la longitud prearticular. El principal resultado es una correlacion positiva para los generos Gyrodus y Proscinetes de la Baja Sajonia (NO de Alemania) y de la zona de Solnhofen (S de Alemania), para futuros estudios paleobiologicos. EnglishPycnodontiform fishes are a well-known group, represented in many conservation Lagerstatten worldwide. They occur from the Late Triassic to the Eocene, and some genera were distributed worldwide. Much work has been done during the last centuries, but most scientists studied the taxonomy. The palaeobiology of the Pycnodontiformes has been rarely the central question in their publications. This paper presents a method to reconstruct the standard length by the means of the prearticular length. The main result is a positive correlation between the prearticular length and the standard length, that it is possible to reconstruct the standard length of Gyrodus and Proscinetes from Lower-Saxony (NW-Germany) and the Solnhofen area (S-Germany) for paleobiological studies.
Pycnodontiform fishes are a well-known group, represented in many conservation Lagerstatten worldwide. They occur from the Late Triassic to the Eocene, and some genera were distributed worldwide. Much work has been done during the last centuries, but most scientists studied the taxonomy. The palaeobiology of the Pycnodontiformes has been rarely the central question in their publications. This paper presents a method to reconstruct the standard length by the means of the prearticular length. The main result is a positive correlation between the prearticular length and the standard length, that it m. Licht The relationship of prearticular length and standard length in pycnodontiform fishes
Starting in the Late Permian, the “Triassic osteichthyan revolution” gave rise to several new morphotypes of actinopterygians, including the iconic barracuda-shaped predator Saurichthys. About 50 species, from 10 cm to over 1.5 m long, are known from mainly marine deposits worldwide. Despite current interest in Saurichthys, freshwater species and those from late Middle to early Late Triassic remain understudied. We document the postcranial morphology of three small to mid-sized (15–45 cm) species from this timeframe represented by sufficiently complete individuals: Saurichthys orientalis Sytchevskaya, 1999, from lacustrine deposits of the Madygen Formation (late Ladinian/Carnian); S. striolatus (Bronn, 1858) from the fully marine Predil Limestone (early Carnian); and S. calcaratus Griffith, 1977, from the terrigenously influenced coastal environment of the Lunz Formation (middle Carnian). S. orientalis resembles early saurichthyids in having six rows of large, thick ganoid scales; fins with segmented lepidotrichia; and flank scales relating to dorsal vertebral elements as 1:2. S. calcaratus and S. striolatus share unsegmented fin rays and a reduced scale cover with well-ossified but narrow mid-dorsal and mid-ventral scales and small, thin flank scales, relating to the dorsal arcualia as 1:1. Ventral arcualia are first described for S. calcaratus and S. striolatus, where they change in shape and number at the abdominal-caudal transition. In all three species, force transmission to the tail fin is enhanced by the caudal peduncle strengthened by a stiff structure arising from interlocking or fusion of the last enlarged mid-dorsal and mid-ventral scales (scutes), while the vertebral column remains rather lightly built.
