Species and sex specific chemical composition in a concealed gland from an internal gland-like tissue of an African frog family

Intraspecific chemical communication in frogs is understudied and the few published cases are limited to externally visible and male-specific breeding glands. Frogs of the family Odontobatrachidae, a West African endemic complex of five morphologically cryptic species, have large, fatty gland-like strands along their lower mandible. We investigated the general anatomy of this strand and analyzed its chemical composition. We found the strand to be present in males and females of all species. The strand varies in markedness, with well-developed strands usually found in reproductively active individuals. Although the strands are situated under the skin, they are connected to particular skin sections, the vocal sac in male frogs and a respective area in females. Gas-chromatography/mass spectrometry and multivariate analysis revealed, that the strands contain sex- and species-specific chemical profiles, which are consistent across geographically distant populations. The profiles varied betwe..., We collected specimens of all five Odontobatrachus species, O. arndti, O. fouta, O. natator, O. smithi and O. ziama. We euthanized, killed and dissected the animals to obtain tissue samples for chemical analysis. Tissue samples where then extracted in dichloromethane and analyzed by gas chromatography/mass spectrometry (GC/MS). To search for sex and species-specific differences in gland composition, we sampled both sexes of each species from at least two locations per species. We also sampled O. arndti under wet and dry season conditions on the same river, to screen for seasonal effects. To check for the effect of geographical distance between populations, we sampled O. arndti males and O. smithi females over a large part of their distribution range. To investigate ontogenetic effects on strand composition, we sampled metamorphic and sub-adult O. ziama frogs and compared them to sexually mature animals. For histological and anatomical analyses, we used voucher specimens from the collect..., , # Species and sex specific chemical composition in a concealed gland in an internal tissue of an African frog family - Electronic Supplement

Contains 6 files: includingone csv file with original GCMS data (1), one csv file with geospatial data (2), one excel file with additional peak information for the GCMS data file (3), and two high-resolution histological crosssection scans of the mandibular strand in a male and female *Odontobatrachus arndti (4), as well as the annotated R Code. Scans and Code are stored in Zenodo as Supplementary and Software respectively.

Description of the data and file structure

1. GC_data.csv (the original GCMS data): depicts metadata and GC count data for the 161 strand samples (ZFG_XXX) from 1178 peaks and contains the following relevant columns: \"ID\"= sample identification, \"species\" = species identification \"date\"= day of collection, \"season\"= corresponding wet or dry season, \"river\"=name of river where sample was collected, \"size\"= bodysize (SVL)...