Glanapteryginae

Glanapteryginae
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Siluriformes
Family:	Trichomycteridae
Subfamily:	Glanapteryginae; Myers, 1944
Type genus
	Glanapteryx; Myers, 1927
Genera
	Glanapteryx; Listrura; Pygidianops; Typhlobelus

The Glanapteryginae are a subfamily of catfishes (order Siluriformes) of the family Trichomycteridae. It includes four genera, Glanapteryx, Listrura, Pygidianops, and Typhlobelus.^[1]

Phylogeny

synapomorphies involving reductions in the fins, caudal skeleton, and laterosensory system.^[1] It has been proposed that the sister group to this subfamily is the Sarcoglanidinae.^[1] Listrura is the sister group

to the remainder of the subfamily. Glanapteryx is sister to a clade formed by the sister taxa Pygidianops and Typhlobelus.

Distribution

Glanapteryx, Pygidianops, and Typhlobelus are distributed in the

Amazon River basins. Listrura species are from Brazil, outside of the Amazon River basin.^[1] However, the distribution of glanapterygines may be greater than previously thought.^[1]

Description

Most of the subfamily is constituted by 'miniaturized' species. Though miniaturized fish usually refers to fish that do not reach 25.4 mm (1.0 in)

paedomorphic features and small head sizes, despite their lengths exceeding an inch.^[2]

Pygidianops and Typhlobelus are the most modified glanapterygines, sharing extreme reduction or loss of pigmentation, fins, laterosensory system, and eyes; they are also miniaturized, yet retain the well-ossified skeleton comparable in both bone differentiation and degree of calcification to that observed in larger trichomycterids.^[1] All four of these genera are currently monophyletic.^[1]

Habitat

Glanapterygine phylogeny indicates the evolution of the group followed a trend of decreasing dependence on

benthic organisms. The latter two genera are more specialized for this lifestyle than any other catfishes, as evidenced by their loss of morphological traits. These two species also have paired keels, called metapleural keels, formed by long ridges of stiffened integument, extend along the entire ventral margin of the abdomen, ending posteriorly shortly posterior to the anus. These keels probably serve to stabilize the body while moving in sand.^[1]

References

^
S2CID 19506818
.

^ de Pinna, Mario C. C. (August 9, 1989). "A New Sarcoglanidine Catfish, Phylogeny of Its Subfamily, and an Appraisal of the Phyletic Status of the Trichomycterinae (Teleostei, Trichomycteridae)" (PDF). American Museum Novitates (2950): 1–39.

[Schaefer-1] 
S2CID 19506818
.

[de_Pinna-2] Pinna, Mario C. C. (August 9, 1989). "A New Sarcoglanidine Catfish, Phylogeny of Its Subfamily, and an Appraisal of the Phyletic Status of the Trichomycterinae (Teleostei, Trichomycteridae)" (PDF). American Museum Novitates (2950): 1–39.

[1]

[2]