Abstract This is the first study addressing validation of early growth stages (including increment) in beaks juvenile cuttlefishes. The age juveniles Sepia officinalis was performed by comparison number increments observed rostrum surface lower jaws with their true age. A total 159 individuals were reared at 18 ºC and 21 ºC, ages up to 31 days from hatching. beak counted contrasted life after h...

A new fossil caridean shrimp, Kellnerius jamacaruensis n. gen. n. sp., of the early Cretaceous (Albian) from the Romualdo Formation, Araripe Basin, northeastern Brazil is described and illustrated. The new species is compared to known fossil palaemonids found in Brazil. Kellnerius jamacaruensis n. gen. n. sp. is easily differentiated from the other palaemonids by a rostrum with 5 spines, an enl...

The genus Calliapagurops was established by de Saint Laurent (1973) for the new species C. charcoti based on a damaged specimen lacking the abdomen and both third and fourth pereopods. The specimen was collected south of the Azorean island of Flores from shelly sand in 190–230 m depth. The original description by de Saint Laurent (1973) was rather short; a redescription and figures were later p...

The description of a partial but well preserved head of the sclerorhynchid batoid Sclerorhynchus atavus Woodward, 1889 gave the first clear indication of the presence of a puzzling group of extinct rostrum-bearing rays that resembled both the Pristidae (rays) and the Pristophoridae (sharks). Despite recognizing similarities and differences to these extant groups, Woodward suggested that Scleror...

Extremely divergent traits between males and females are often the result of different requirements and behaviours of the sexes and will evolve relatively rapidly under selection forces. Sexual dimorphism in Rhopalapion longirostre is predominately manifested in the length and structure of the rostrum. To estimate how sexual selection shapes mating success in this weevil we compared paired and ...

To estimate how extensively the ensemble of denatured-state conformations is constrained by local side-chain-backbone interactions, propensities of each of the 20 amino acids to occur in mono- and dipeptides mapped to discrete regions of the Ramachandran map are computed from proteins of known structure. In addition, propensities are computed for the trans, gauche-, and gauche+ rotamers, with o...

A new species, Strongylacron glabrum sp. n. is described from intertidal mudflats in the Korean peninsula. The new species is assigned to the monospecific genus Strongylacron Gee & Huys, 1996 in accordance with the generic morphological features of the rostrum, antennary exopod, and thoracic legs. However, Strongylacron glabrum sp. n. is clearly distinguished from the type species, Strongylacro...

Although there are nine genera of ctenochasmatoids reported from the Jehol Biota, at present each is known from a specimen that has either a skull or a relatively complete postcranial skeleton. A nearly complete juvenile specimen of Gladocephaloideus from the Lower Cretaceous Jiufotang Formation of Sihedang, Lingyuan of Liaoning Province is the most complete ctenochasmatoid preserved to date wi...