Sexual dimorphism in aipysurine sea snakes
Data files
Sep 04, 2023 version files 39.06 KB
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Aipysurine_sex_dimorphism_for_Dryad2.xlsx
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README.md
Abstract
The transition from terrestrial to aquatic life by hydrophiine elapid snakes modified targets of natural selection and likely affected sexual selection also. Thus, the shift to marine life also might have affected sexual dimorphism. Our measurements of 419 preserved specimens of six species of aipysurine snakes (genera Emydocephalus and Aipysurus) revealed sexual dimorphism in mean adult snout-vent length (= SVL), body width relative to SVL, lengths and widths of heads and tails relative to SVL, and eye diameter relative to head length. Females averaged larger than males in all taxa, and generally were wider-bodied with shorter and wider tails and smaller eyes. For other traits, sexual dimorphism varied among species: for example, relative head length ranged from male-biased to female-biased, and head shape (width relative to length) was highly dimorphic only in A. laevis. The transition to marine life appears to have eliminated male-male combat (reducing selection for large males) and favoured visual rather than pheromone-based mate-searching (favouring larger eyes in males). Variation in head-size dimorphism may reflect intersexual niche partitioning, with different taxa following different trajectories. Repeated evolutionary transitions from terrestrial to aquatic life in snakes provide a powerful opportunity to explore selective forces on sexually dimorphic traits.
README: Sexual dimorphism in aipysurine sea snakes
This Excel file contains the following columns:
- A. Genus name
- B. species name
- C. Museum in which specimens are stored (Australian Museum or Museums and Art Galleries of the Northern Territory [=MAGNT])
- D. Museum registration number
- E. Snout-vent length (cm)'
- F. Tail length (cm)
- G. Tail maximum width (cm)
- H. Head length (mm) measured along jawline
- I. Head width (mm) at widest point
- J. Body width at midbody (cm)
- K. Eye diameter (mm)
- L. Sex (f = female, m = male)
- M. Maturity (a = adult, j = juvenile)
In all columns, "0" = missing data due to damaged or incomplete specimen
Methods
Measurements of preserved specimens in museum collections.