Can Phenotypic Plasticity Facilitate the Geographic Expansion of the                     Tilapia Oreochromis mossambicus?

A. K. Schnell; F. Seebacher

doi:10.1086/592027

Can Phenotypic Plasticity Facilitate the Geographic Expansion of the Tilapia Oreochromis mossambicus?

Physiological and Biochemical Zoology ◽

10.1086/592027 ◽

2008 ◽

Vol 81 (6) ◽

pp. 733-742 ◽

Cited By ~ 11

Author(s):

A. K. Schnell ◽

F. Seebacher

Keyword(s):

Phenotypic Plasticity ◽

Oreochromis Mossambicus ◽

Geographic Expansion

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SEM and TEM observations of sperm development in the testis of the freshwater fish Oreochromis mossambicus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157838 ◽

1990 ◽

Vol 48 (3) ◽

pp. 58-59

Author(s):

Daryl A. Cornish ◽

George L. Smit

Keyword(s):

Morphological Characteristics ◽

Oreochromis Mossambicus ◽

Breeding Cycle ◽

Limited Information ◽

North West ◽

The North ◽

Sem And Tem ◽

Sperm Development ◽

Ultrastructural Characteristics ◽

The University

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.

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Ecology and biogeography in the introduction to “De bestiis marinis” by Georg Wilhelm Steller

Archives of Natural History ◽

10.3366/anh.2019.0554 ◽

2019 ◽

Vol 46 (1) ◽

pp. 63-74

Author(s):

Stefano Mattioli

Keyword(s):

Body Size ◽

Phenotypic Plasticity ◽

Geographical Distribution ◽

Functional Traits ◽

Marine Mammals ◽

Main Part ◽

Wide Distribution ◽

Restricted Range ◽

Direct Influence ◽

Modern Biology

The rediscovery of the original, unedited Latin manuscript of Georg Wilhelm Steller's “De bestiis marinis” (“On marine mammals”), first published in 1751, calls for a new translation into English. The main part of the treatise contains detailed descriptions of four marine mammals, but the introduction is devoted to more general issues, including innovative speculation on morphology, ecology and biogeography, anticipating arguments and concepts of modern biology. Steller noted early that climate and food have a direct influence on body size, pelage and functional traits of mammals, potentially affecting reversible changes (phenotypic plasticity). Feeding and other behavioural habits have an impact on the geographical distribution of mammals. Species with a broad diet tend to have a wide distribution, whereas animals with a narrow diet more likely have only a restricted range. According to Steller, both sea and land then still concealed countless animals unknown to science.

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