Biometric Differences Research Articles

A new species of harvestman of the genus Mitopus in Britain

A new species of Mitopus, found in upland regions of Britain, is described. It occurs sympatrically with M. morio in the upper altitudinal parts of the latter's range. The two species are distinguished by their differences in morphology, biometrics and phenology. The new species of Mitopus is larger and longer‐legged than M. morio, and develops faster, reaching maturity at an earlier date.

Differenze biometriche e ponderali tra popolazioni diUnio mancus, Pfeiff

Summary The lammelibraneh, Unio mancus, Pfeiff. was collected from four different stations in Lago Maggiore: Fondotoce, Ispra, Arona and Angera: and four characteristics of the shell of Unio were measured: length, height, width and weight. For each population calculations were made for the correlation factors (r) and the regression coefficients among the different characteristics mentioned above. The Student « t » test was calculated for each characteristics from the mean values calculated for the four populations. Data from the calculations obtained from Unio mancus of Lago di Varese were compared with those data obtained from the Unio populations collected in Lago Maggiore. Significant biometric differences were found between the Unio of Lago Maggiore and those of Lago di Varese as well as among certain of the stations in Lago Maggiore. A certain relation between the biometric values of a population and the amount of Mn54 present in the poulation was pointed out.