External and internal sexual dimorphism in leiognathid fishes: Morphological evidence for sex‐specific bioluminescent signaling

  title={External and internal sexual dimorphism in leiognathid fishes: Morphological evidence for sex‐specific bioluminescent signaling},
  author={Margaret J. McFall-Ngai and Paul V. Dunlap},
  journal={Journal of Morphology},
Fourteen species of leiognathid fishes (Perciformes, Leiognathidae) from the Philippine Islands, Thailand, Japan, Indonesia, and Palau were examined for accessory secondary sexual dimorphism. Thirteen species exhibit either external dimorphism (a clear patch of skin on the flanks of males, a large clear patch of skin on the opercular margins of males, or a flank stripe in males) or internal dimorphism (large light organs in males) or both. Eight of the 14 species (and possibly as many as 11… 

A Clade of Non-Sexually Dimorphic Ponyfishes (Teleostei: Perciformes: Leiognathidae): Phylogeny, Taxonomy, and Description of a New Species

It is shown that the evolution of the leiognathid LOS can be traced from a “simple” non-sexually dimorphic circumesophageal light organ to a complex and species-specific luminescence system involving not only major structural modifications of the light organ itself but also numerous associated tissues.

Evolution of the light organ system in ponyfishes (Teleostei: Leiognathidae)

Both internal and external sexual dimorphism in the ponyfish LOs were recovered as most likely to have evolved in the common ancestor of Leiognathidae, and likelihood‐based correlation analyses indicate that the evolution ofinternal and external dimorphisms in males is statistically correlated.

Leiognathus elongatus (Perciformes: Leiognathidae): Two Distinct Species Based on Morphological and Light Organ Characters

The use of the light-organ system is proposed in clarifying questions of leiognathid taxonomy by recognizing two species: L. stercorarius Evermann and Seale (group I), a previously buried synonym of L. elongatus (Glinther) (group II), which includes fishes previously named Equula elongata Giinther and L. popei (Whitley).

Evolution and diversification of a sexually dimorphic luminescent system in ponyfishes (Teleostei: Leiognathidae), including diagnoses for two new genera

It is hypothesized that the species‐specific, sexually dimorphic internal and external modifications of the leiognathid LOS provide compelling evidence for an assortative mating scheme in which males use species‐ specific patterns of lateral luminescence signaling to attract mates, and that this system functions to maintain reproductive isolation in these turbid coastal environments.

Is sexual selection driving diversification of the bioluminescent ponyfishes (Teleostei: Leiognathidae)?

The results suggest that if sexual selection is occurring in ponyfish evolution, it is likely acting only as a genetic isolating mechanism that has allowed ponyfishes to continuously diversify over time, with no overall impact on increases in diversification rate or morphological disparity.

A New Species of Ponyfish (Teleostei: Leiognathidae: Photoplagios) from Madagascar, with a Phylogeny for Photoplagios and Comments on the Status of Equula lineolata Valenciennes

A phylogeny for Photoplagios is provided based on the simultaneous analysis of anatomical features of the light-organ system and nucleotide characters and the taxonomic status of Equula lineolata Valenciennes is discussed, and the species is concluded to be a nomen dubium of uncertain placement beyond the family level.

Synchronized development of gonad and bioluminescent light organ in a highly sexually dimorphic leiognathid fish, Photoplagios rivulatus

The seasonal changes in the gonad maturation and the light organ enlargement in Photoplagios rivulatus, one of the leiognathid species possessing highly sexually dimorphic LOS, strongly support the functional coupling between reproduction and bioluminescence in this species of lei Cognathid.

The Leiognathus aureus complex (Perciformes: Leiognathidae) with the description of a new species

Taxonomic analysis of a group of morphologically similar ponyfishes (Perciformes: Leiognathidae) establishes a complex comprising three valid species: Leiognathus aureus Abe and Haneda, 1972, widely

Life history of the symbiotically luminous cardinalfish Siphamia tubifer (Perciformes: Apogonidae).

Characteristics of the life history of the coral reef-dwelling cardinalfish Siphamia tubifer, from Okinawa, Japan, were defined and indicate that once settled, S. tubifer grows quickly, reproduces early and typically survives much less than 1 year in Okinawa.

The Leiognathus splendens complex (Perciformes: Leiognathidae) with the description of a new species, Leiognathus kupanensis Kimura and Peristiwady

Taxonomic analysis of a group of morphologically similar ponyfishes establishes the Leiognathus splendens complex comprising four valid species, which can be defined by the following combination of characters: body depth 42–60% of standard length; mouth protruding downward; slender, minute teeth uniserially on jaws.



Three new modes of luminescence in the leiognathid fish Gazza minuta: Discrete projected luminescence, ventral body flash, and buccal luminescence

Three new modes of luminescence are described for Gazza minuta (Bloch) (Perciformes: Leiognathidae) as observed in specimens collected in the Philippines in April and May, 1982: discrete projected


The isolated symbiotic bacteria were compared with free living bacteria isolated directly from sea water in the same area where the fish were collected, and it was possible to estimate the total number of viable bacteria within an organ, and to compare this with the weight of the organ.

Adaptations for reflection of bioluminescent light in the gas bladder of Leiognathus equulus (Perciformes: Leiognathidae).

  • M. McFall-Ngai
  • Environmental Science
    The Journal of experimental zoology
  • 1983
The enhancement of purine in the reflective portions of the bladder and the correlation of the differential distribution of purines with the path of light indicate that the L. equulus gas bladder is exquisitely adapted to function as a reflector of bioluminescent light.

Light for All Reasons: Versatility in the Behavioral Repertoire of the Flashlight Fish

The flashlight fish, Photoblepharon, possesses headlight-like luminous organs situated in the orbit just below the eyes, and it is postulated that the bioluminescence is used by the fish to assist in obtaining prey, to deter or escape predators, and for intraspecific communication.

The Luminescent Systems of Pony Fishes

The anatomy of bioluminescent organs and mode of light production in 18 species of pony fish have been investigated using fresh and preserved material and a simple classification of the luminescent systems is proposed.

Light to Hide by: Ventral Luminescence to Camouflage the Silhouette

An experimental analysis of this luminescent system supports the hypothesis that it functions by emitting light during the daytime, which matches the background light and thereby obscures the silhouette of the animal.

Why do Fish School?

Studies of fish behaviour suggest that the habit of schooling, whatever its mechanism, is an advantage to potential prey.