Sexual dimorfism refers to morphological differences between males and females of a species. It m... more Sexual dimorfism refers to morphological differences between males and females of a species. It may be a result of different selection pressures acting on either or both sexes and may occur in any sexually-reproducing dioecious species, including fishes. We analyzed 63 females and 63 adult males of Gymnorhamphichthys rondoni (Gymnotiformes) collected by us or deposited in museum collections. Sex was identified through abdominal dissection. We measured length from snout to posterior end of anal-fin, anal-fin length, distance from anus to anal-fin origin, distance from genital papilla to anal-fin origin, body width at beginning of anal-fin, and head length. Morphometric data submitted to a Principal Component Analysis (PCA) grouped males and females according to variables related to body size (along the first component) and to head length and body height along the second and third components. Females were larger than males, whereas males had proportionally larger heads and higher bodi...
Sexual dimorfism refers to morphological differences between males and females of a species. It m... more Sexual dimorfism refers to morphological differences between males and females of a species. It may be a result of different selection pressures acting on either or both sexes and may occur in any sexually-reproducing dioecious species, including fishes. We analyzed 63 females and 63 adult males of Gymnorhamphichthys rondoni (Gymnotiformes) collected by us or deposited in museum collections. Sex was identified through abdominal dissection. We measured length from snout to posterior end of anal-fin, anal-fin length, distance from anus to anal-fin origin, distance from genital papilla to anal-fin origin, body width at beginning of anal-fin, and head length. Morphometric data submitted to a Principal Component Analysis (PCA) grouped males and females according to variables related to body size (along the first component) and to head length and body height along the second and third components. Females were larger than males, whereas males had proportionally larger heads and higher bodies than females. The urogenital papilla of males and females showed differences in shape, size and relative position on the body. The female papilla was elongated horizontally, larger than that of males, and was located on a vertical line below the eye, while the papilla of the males was vertically elongated and located on a vertical line below the operculum. To our knowledge, this is the first recorded case of sexual dimorphism in a species of Rhamphichthyidae, a condition that is now known in all the currently recognized families of Gymnotiformes.
Sexual dimorfism refers to morphological differences between males and females of a species. It m... more Sexual dimorfism refers to morphological differences between males and females of a species. It may be a result of different selection pressures acting on either or both sexes and may occur in any sexually-reproducing dioecious species, including fishes. We analyzed 63 females and 63 adult males of Gymnorhamphichthys rondoni (Gymnotiformes) collected by us or deposited in museum collections. Sex was identified through abdominal dissection. We measured length from snout to posterior end of anal-fin, anal-fin length, distance from anus to anal-fin origin, distance from genital papilla to anal-fin origin, body width at beginning of anal-fin, and head length. Morphometric data submitted to a Principal Component Analysis (PCA) grouped males and females according to variables related to body size (along the first component) and to head length and body height along the second and third components. Females were larger than males, whereas males had proportionally larger heads and higher bodi...
Sexual dimorfism refers to morphological differences between males and females of a species. It m... more Sexual dimorfism refers to morphological differences between males and females of a species. It may be a result of different selection pressures acting on either or both sexes and may occur in any sexually-reproducing dioecious species, including fishes. We analyzed 63 females and 63 adult males of Gymnorhamphichthys rondoni (Gymnotiformes) collected by us or deposited in museum collections. Sex was identified through abdominal dissection. We measured length from snout to posterior end of anal-fin, anal-fin length, distance from anus to anal-fin origin, distance from genital papilla to anal-fin origin, body width at beginning of anal-fin, and head length. Morphometric data submitted to a Principal Component Analysis (PCA) grouped males and females according to variables related to body size (along the first component) and to head length and body height along the second and third components. Females were larger than males, whereas males had proportionally larger heads and higher bodies than females. The urogenital papilla of males and females showed differences in shape, size and relative position on the body. The female papilla was elongated horizontally, larger than that of males, and was located on a vertical line below the eye, while the papilla of the males was vertically elongated and located on a vertical line below the operculum. To our knowledge, this is the first recorded case of sexual dimorphism in a species of Rhamphichthyidae, a condition that is now known in all the currently recognized families of Gymnotiformes.
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Papers by Elisa Garcia
selection pressures acting on either or both sexes and may occur in any sexually-reproducing dioecious species, including fishes.
We analyzed 63 females and 63 adult males of Gymnorhamphichthys rondoni (Gymnotiformes) collected by us or deposited
in museum collections. Sex was identified through abdominal dissection. We measured length from snout to posterior end
of anal-fin, anal-fin length, distance from anus to anal-fin origin, distance from genital papilla to anal-fin origin, body width
at beginning of anal-fin, and head length. Morphometric data submitted to a Principal Component Analysis (PCA) grouped
males and females according to variables related to body size (along the first component) and to head length and body height
along the second and third components. Females were larger than males, whereas males had proportionally larger heads and
higher bodies than females. The urogenital papilla of males and females showed differences in shape, size and relative position
on the body. The female papilla was elongated horizontally, larger than that of males, and was located on a vertical line below
the eye, while the papilla of the males was vertically elongated and located on a vertical line below the operculum. To our
knowledge, this is the first recorded case of sexual dimorphism in a species of Rhamphichthyidae, a condition that is now
known in all the currently recognized families of Gymnotiformes.
selection pressures acting on either or both sexes and may occur in any sexually-reproducing dioecious species, including fishes.
We analyzed 63 females and 63 adult males of Gymnorhamphichthys rondoni (Gymnotiformes) collected by us or deposited
in museum collections. Sex was identified through abdominal dissection. We measured length from snout to posterior end
of anal-fin, anal-fin length, distance from anus to anal-fin origin, distance from genital papilla to anal-fin origin, body width
at beginning of anal-fin, and head length. Morphometric data submitted to a Principal Component Analysis (PCA) grouped
males and females according to variables related to body size (along the first component) and to head length and body height
along the second and third components. Females were larger than males, whereas males had proportionally larger heads and
higher bodies than females. The urogenital papilla of males and females showed differences in shape, size and relative position
on the body. The female papilla was elongated horizontally, larger than that of males, and was located on a vertical line below
the eye, while the papilla of the males was vertically elongated and located on a vertical line below the operculum. To our
knowledge, this is the first recorded case of sexual dimorphism in a species of Rhamphichthyidae, a condition that is now
known in all the currently recognized families of Gymnotiformes.