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Abstract PremiseAntheridiogen systems are a set of pheromonal mechanisms that control sex expression in fern gametophytes. However, antheridiogen has rarely been studied outside of the laboratory, and little is known about its function in natural settings. Combining predictions based on field and laboratory study, we tested whether the sexual structure of gametophytic colonies of a tree fern were attributable to antheridiogen. MethodsGametophytic colonies of the antheridiogen‐producing tree fernCyathea multiflorawere collected at La Selva Biological Station in Costa Rica in January 2019. The sex of each gametophyte was determined, mapped, and spatial statistic approaches were used to examine the distribution of sex in each colony. ResultsIn all gametophytic colonies, males were most common, representing 62–68% of individuals. No hermaphroditic gametophytes were identified in any colony. A quadrat‐based method showed female gametophytes were not clustered in each colony, while male gametophytes were clustered. In two of the colonies, theK(r) test statistic for males was greater than expected compared to random simulations of sex expression, indicating male sex expression was spatially associated with females. ConclusionsThis study provides the first documentation of spatial sex expression in natural settings of gametophytes of an antheridiogen‐producing tree fern species. The profound impact of antheridiogen on gametophytic sex expression in field settings suggests this system is intimately tied to mating system, fitness, and genetic diversity inCyathea multiflora.
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Talon cusp expression in Cayo Santiago rhesus macaques ( Macaca mulatta )
Abstract ObjectivesThis brief communication documents the prevalence of maxillary central incisor talon cusps in Cayo Santiago rhesus monkeys (Macaca mulatta) and assesses whether talon cusp presence occurs at equivalent frequencies across matrilines. Materials and MethodsThe data on cusp presence vs. absence were analyzed by logistic regression in 170 monkeys (82 females, 78 males) from seven different matrilines. Sample sizes per matriline ranged from 10 to 42. Observations of talon cusps were blind with respect to matriline and sex. ResultsTalon cusps were present in 9.4% of the sample. By matriline, cusp frequencies ranged from 0%—Matrilines 073 and 106%—to 19.1% in Matriline 076. The frequency of the talon cusp in Matriline 076 was significantly greater than the frequency of the cusp in the remainder of the sample. There was no statistically significant difference in the frequency of the talon cusp by sex. ConclusionsThis study suggests that the talon cusp in rhesus monkeys, as in humans and baboons, is a rare trait. Elevated prevalence of the talon cusp in Matriline 076 suggests the possibility of a genetic influence on talon cusp expression.
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- Award ID(s):
- 1926601
- PAR ID:
- 10536816
- Editor(s):
- Turner, Trudy
- Publisher / Repository:
- John Wiley & Sons
- Date Published:
- Journal Name:
- American Journal of Biological Anthropology
- Volume:
- 183
- Issue:
- 1
- ISSN:
- 2692-7691
- Page Range / eLocation ID:
- 172 to 177
- Subject(s) / Keyword(s):
- dental incisors morphogenesis morphology teeth
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/ajpa.24855
