The stem-group euarthropod Anomalocaris canadensis is one of the largest Cambrian
animals and is often considered the quintessential apex predator of its time. This radiodont …

Animal contests involve threatening displays and physical coercion, which are respectively
performed by threat devices used in mutual evaluation of size or strength, and weapons …

The link between form and function is key to understanding the evolution of unique and/or
extreme morphologies. Amblypygids, or whip spiders, are arachnids that often have highly …

Megalograptidae and Mixopteridae with elongate, spinose prosomal appendages are
unique early Palaeozoic sea scorpions (Eurypterida). These features were presumably used …

Whip scorpions (Thelyphonida) and schizomids (Schizomida) are closely related arachnid
orders, whose low species diversity compared to other arachnid groups is reflected in a …

Amblypygi are tropical and subtropical ambush predators that use elongated, raptorial
pedipalps for different activities. Although pedipalp use in predation and courtship has been …

Sexual size dimorphism (SSD) characterized by different body size between females and
males have been reported in various animals. Gonadectomy experiments have implied …

First mixopterid eurypterids (Arthropoda: Chelicerata) from the Lower Silurian of South
China First mixopterid eurypterids (Arthropoda: Chelicerata) from the Lower Silurian of …

Sexual size dimorphism (SSD), characterized by the body size difference in different sexes,
has been commonly announced in various species included mammals, birds, reptiles, and …

A peculiar intraspecific agonistic behavior involving a non-aggressive physical combat is
reported between the adult males of Srilankametrus yaleensis (Kovařík et al …