Laughingthrush

Laughingthrush
Masked Laughingthrush
Garrulax perspicillatus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Timaliidae
Genus: Garrulax
Lesson, 1831
Species

Presently about 50, but see text

The Laughingthrushes are the genus Garrulax of the large Old World babbler family of passerine birds. They occur in tropical Asia, with the greatest number of species occurring in the Himalaya and southern China.

These are rangy, medium-sized, floppy-tailed landbirds with soft fluffy plumage. These birds have strong legs and are quite terrestrial. This group is not strongly migratory, and most species have short rounded wings, and a weak flight.

A few, like the Streaked Laughingthrush occur in fairly open habitats, but most are jungle species, difficult to observe in the dense vegetation they prefer.

Like other babblers, these are noisy birds, and the characteristic laughing calls are often the best indication that these birds are present. As with other babbler species, they frequently occur in groups of up to a dozen, and the rainforest species like the Ashy-headed Laughingthrush often occur in the mixed feeding flocks typical of tropical Asian jungle.

Contents

Systematics

As with some other babblers, this genus has turned out to be highly polyphyletic. Rather than forming a natural evolutionary group of closest relatives, the laughingthrushes are spread about the entire babbler family. This is quite apparent by their diverse morphology and presence of several groups with distinct color patterns, but the rarity of several species and the sheer number of taxa have hitherto prevented a thorough revision. Before this paraphyly was realized to be as dramatic as it is, it was generally assumed that the laughingthrushes were a clade comprising several subgenera.

This has much confounded further research: most molecular phylogeny studies, for example, used only the White-crested Laughingthrush as an "example" of this "genus", because specimens were readily available. Morphological studies, on the other hand, had usually more material at their disposal, but these too were generally conducted under a false assumption of monophyly. A 2003 study,[1] analyzing mtDNA cytochrome b and 12S/16S rRNA data of a number of laughingthrushes, did establish however that there is no such thing as a "representative" laughingthrush. Consequently most of the work regarding the evolution of this assemblage needs to be evaluated anew and if necessary even redone. Indeed, the taxon Garrulax would need to be restricted to the type species (Rufous-fronted Laughingthrush) and its closest relatives, but the species generally considered the most likely candidates have not been comprehensively studied in recent times.[2]

Species list

The list below uses the treatment of the laughingthrushes by Birds of South Asia[3] and the Handbook of Birds of the World[4] as a baseline, acknowledging the polyphyly of Garrulax and attempting to reorganise it into monophyletic genera.

This list is by no means the last word on the subject though, and it is very likely that some of the new groups will be revised, expanded or split as more species are studied in the future; additional laughingthrushes are presently elevated to species status and even hitherto unknown taxa are discovered at a rate of about 1-2 per year. Some proposed small or monotypic genera on the other hand might ultimately be merged with others for convenience if they turn out to be sister taxa. All in all, the resolution of the laughingthrush assemblage's taxonomy depends on a resolution of the Old World babblers' systematics in general.

References

  1. ^ Cibois (2003)
  2. ^ Cibois (2003), Pasquet et al. (2006)
  3. ^ Rasmussen & Anderton (2005)
  4. ^ Collar & Robson (2007)
  5. ^ But see Pasquet et al. (2006)

External links