摘要:

Three major social systems were observed: territorial, isolate, and gregarious. Territorials defend a particular area against intruders. Isolates neither chase conspecifics nor join other individuals, while gregarious species are found in groups. Some species of territorial pomacentrids were found in uni‐specific colonies. As gregarious groups neared these colonies, they were attacked by several territorials. The number of chases directed against the various species of intruders was in proportion to the intruder's abundance in the study areas. Predators were uncommon and generally ignored. Isolates were either predators, or slow moving species. Gregarious species could be found in uni‐specific or mixed‐species groups. In mixed‐species groups, there were three subunits: core, associate, and opportunist. Core species were always in the majority and led the group. Associates followed the core species for long periods of time and the opportunists were brief visitors. Quantitative comparisons between uni‐specific and mixed‐species groups revealed that associates tend to select the larger of the available core groups. Juveniles were also considered and compared to their adults. Juveniles did exhibit the general types of social behaviour found in adults. However, within a species, the adult's behaviour may be very different from their own juveniles. The coral, and the chases by pomacentrids, were related to the formation and dispersion of gregar

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1974.tb01589.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

An osteological study and a taxonomic diagnosis are presented for the mesopelagic, oviparous ophidioid fish genusBrotulataenia.Its relationships are probably with a large group of benthic deep‐sea oviparous genera.Brotulataeniahas been known previously from three North Atlantic specimens assigned to two species. The present study is based on 33 specimens from the North and South Atlantic and Pacific Oceans and the Indian Ocean, and placed in four species, two of which are described as new. Two species are excessively elongate and are interpreted as being derived forms; they are lighter in color than are the two short‐bodied species and may live higher in the water col

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1974.tb01590.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

A new species of ornithischian dinosaur (Lycorhinus consorssp. nov.) is established on a skull from the Upper Triassic Red Beds of Lesotho. This ornithischian is assigned to the family Heterodontosauridae of the suborder Ornithopoda. The dinosaurs of the family Heterodonto‐sauridae are reviewed:Geranosaurus atavusBroom (1911) is considered anomendubiumand the genus nameHeterodontosaurusCrompton&Charig (1962) is held to be a junior synonym forLycorhinusHaughton (1924).Functional and palaeoecological implications of the heterodontosaurid dentition are discussed. The pattern of tooth wear may reflect a highly specialized jaw action which involved protraction and retraction of the mandible to produce a grinding effect between upper and lower cheek teeth.Lycorhinus consorsis presumed to be a female heterodontosaurid because it differs from all other heterodontosaurids in lacking caniniform tusks. It is suggested that the tusks of heterodontosaurids were functionally analogous to those of tayassuids and tragulids and that they were employed as weapons for intra‐specific combat and defence. Dental peculiarities indicate that tooth replacement processes were suppressed in heterodontosaurids; replacement of the teeth seems to have been restricted to a brief period each year (presumably when heterodontosaurids underwent aestivation or hibernation).A new diagnosis is formulated for the family Heterodontosauridae. The relationships of early ornithopod dinosaurs are briefly reviewed and a new classification is proposed. Ten families of ornithopod dinosaurs are recognized; these are ranked in two grades‐one (named Dolichopoda) representing the conservative main stem of the ornithischian phylogenetic tree and the other (named Brachypoda) comprising the several more advanced lines of ornithopod evol

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1974.tb01591.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY