Family histories and the demography of grandparenthood

BACKGROUND Grandparenthood is an important phase of life for many individuals, and the grandparent role has consequences on younger generations and grandparents themselves. OBJECTIVE Despite the importance of the grandparent role, little is known about the demography of grandparenthood. In this study, we examine the variability of demographic aspects of grandparenthood (being a grandparent, number of grandchildren, having at least one young grandchild) according to family (partnership and fertility) histories. METHODS Using retrospective data from the Survey of Health, Ageing and Retirement in Europe (SHARE), we employ sequence and cluster analyses to group individuals according to similar patterns of fertility and partnership histories observed between age 15 and 49. In a second step, we use logistic and Poisson regressions to quantify how demographic aspects of grandparenthood vary across the identified family clusters at different ages and by gender. RESULTS Family histories are greatly heterogeneous with respect to timing, quantum, and probability of experiencing certain events. This heterogeneity is reflected in a strong variability in the probability of having (young) grandchildren and their number at different ages across the clusters of family trajectories. CONTRIBUTION We provide a detailed profile of three demographic characteristics of grandparenthood that significantly influence the opportunity structure for the development of the grandparent role. Our study quantifies considerable heterogeneities in the demography of grandparenthood according to different typologies of family histories and has important implications for the understanding of current and possible future developments of the grandparent role

Eocene round herring from Monte Bolca, Italy

Fishes of the subfamily Dussumieriinae, also known as round herrings, are a small subgroup of the family Clupeidae inhabiting tropical and subtropical marine coastal waters. A new genus and species of round herring, Trollichthys bol-censis gen. et sp. nov., is described from the lower Eocene micritic limestone of Monte Bolca, northern Italy. This new clupeid taxon is based on seven partially complete articulated skeletons that exhibit a unique combination of features, including: two supramaxillae, edentulous jaw and palate bones, 41–42 preural vertebrae and 22–24 pleural ribs, pleural ribs-preural vertebrae ratio ranging 0.52–0.57, five or six supraneural bones, dorsal-fin origin located at about mid-length of the body, dorsal fin with about 16 rays, two postcleithra, pelvic-fin insertion slightly behind the dorsal-fin origin, and pelvic fin with eight rays. Trollichthys bolcensis shares several features with the extant round herring genus Spratelloi-des. However, because of its unique combination of features, Trollichthys bolcensis cannot be confidently assigned to any of the extant dussumieriine lineages and present evidence does not favour any particular sister-group relationship