First record of the Hauxwell’s Thrush, Turdus hauxwelli Lawrence, 1869 (Aves: Turdidae) from Mato Grosso do Sul, Brazil, and geographic range extension

We report the first record of the Hauxwell’s Thrush, Turdus hauxwelli Lawrence, 1869 (Aves: Turdidae) in the state of Mato Grosso do Sul, Brazil. During an ornithological inventory conducted in Serra de Maracajú, municipality of Corguinho, we mist-netted and collected an individual of the species. The specimen was prepared as study skin and is held in the ornithological collection of the Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro. This record is located 472 km south of the closest visual/song record and 616 km southeast of the closest museum specimen, being the southernmost occurrence of this thrush.


Introduction
The Hauxwell's Thrush, Turdus hauxwelli Lawrence, 1869, is a monotypic passerine of the Turdidae family found in upper Amazonia in southeastern Colombia (Orinoco region), eastern Ecuador and Peru, northern Bolivia (Reyes, next to the Bení River) and western Brazil (east of the Purus River) (Hellmayr 1934, Deignan et al. 1964, Ridgely and Tudor 2009, Collar 2016).Although the taxonomy of this species is historically controversial, with some authors considering it to be conspecific with the Pale-vented (T.obsoletus Lawrence, 1862) and Cocoa Thrushes (T.fumigatus Lichtenstein, 1823) (Hellmayr 1934, Deignan et al. 1964, Snow 1985), recent studies consider it as a separate but sister species of T. fumigatus based on plumage, molecular and ecological data (Voelker et al. 2007, Ridgely and Tudor 2009, O'Neill et al. 2011, Dickinson and Christidis 2014, Collar 2016).Turdus hauxwelli has also been mistaken as the Várzea Thrush (Turdus sanchezorum O'Neill et al. 2011), a species NOTES ON GEOGRAPHIC DISTRIBUTION only recently described.Although historically mistaken, these 2 taxa have well marked morphological, vocal and ecological differences (O'Neill et al. 2011).Furthermore, molecular data support a distant relationship between them and place T. sanchezorum in a different clade with the Spectacled Thrush (T.nudigenis Lafresnaye, 1848) (O'Neill et al. 2011) and that they are sister species to T. nudigenis (Cerqueira et al. 2016).
Its natural habitat comprises the humid lowland forests, including areas of terra firme, but mostly várzea and other stands near water up to 800 m, but usually below 400 m (Ridgely andTudor 2009, Collar 2016).Both sexes have similar plumage being rufous-brown above, slightly stronger on rump, with dark-streaked whitish throat, whitish belly and vent, the latter with brown tips, pale-orange underwing-coverts and brownish-gray bill and tarsus.Although its conservation status is classified as Least Concern, it is locally uncommon due its shy and presumably sedentary habits (Ridgely andTudor 2009, Collar 2016).Records in Brazil are scarce.
Here we report the first record of T. hauxwelli in Mato Grosso do Sul state, Brazil, based on a single specimen collected in the Serra de Maracajú, municipality of Corguinho.

Methods
During an ornithological inventory from 22 to 27 September 2015 in the rural area of the municipality of Corguinho, Mato Grosso do Sul, Brazil, at the Reserva Particular do Patrimônio Natural (RPPN), Vale do Bugio (19°56ʹ56ʺ S, 055°04ʹ13ʺ W, 365 m) (Fig. 1) , we mistnetted an individual of T. hauxwelli.The local vegetation is a fragment of Cerradão (semi-deciduous forest), a phytophysiognomy of Cerrado, in this case with various influences of Amazonian, Atlantic and Chaco forests (Damasceno et al. 2000, Ramos andSartori 2013).The study site is located in the central portion of the Serra de Maracajú, a geological formation made of sedimentary and volcanic rocks.This plateau extends over the Paraná river basin from northern to central Mato Grosso do Sul state and forms a natural divide between the Pantanal and Cerrado biomes (Boggiani et al. 1998).
The individual was captured on 25 September 2015 at approximately 06:00 h using a mist-net placed close to a small creek.It was immediately measured using a measuring tape (total length and wingspan) and weighed using a Pesola ® scale.All information regarding molting, coloration of soft parts, and parasites were taken in Gonads were examined in the laboratory to determine the specimen's sex.The carcass was fixed in 4% formalin, subsequently preserved in 70% ethanol and given the same accession number as the skin.A tissue sample was taken from the breast and stored in alcohol 100% (accession number MNT 4286).
Historical distribution records of T. hauxwelli were obtained from careful research of the literature and specimens deposited in scientific collections.Data on the specimens held in North American collections were obtained from the Vertnet.orgdatabase (http://vertnet.org/) and data on specimens held at Museu Nacional, UFRJ (MN), Museu de Zoologia, Universidade de São Paulo (MZUSP) and Instituto Nacional de Pesquisas da Amazônia (INPA) were taken personally.Data regarding visual (photographs) and song records were found in WikiAves (WA) and Xeno-canto (XC) databases (wikiaves.com.br and xeno-canto.org).

Results
The bird was identified in the field by all authors using specialized literature (Ridgely and Tudor 2009) and was furthered compared to the existent series of the genus Turdus held in MN, MZUSP, INPA, and photographs of some specimens held at Museu Paraense Emílio Goeldi (MPEG).Identity of the species was confirmed based on the following diagnostic features: dark brown bill, mostly warm brown plumage and white mid-belly and crissum (Fig. 2).Turdus hauxwelli is very similar to its closest related species, the Cocoa Thrush (T.fumigatus Lichtenstein, 1823), which is overall more rufescent and much more buff on belly and crissum (Ridgely andTudor 2009, O'Neill et al. 2011) (Fig. 2).It has been historically reported that in areas of sympatry, such as the north bank of lower Rio Solimões and lower Rio Madeira, both species can present some intermediate plumage features that include the saturation of the rufescent color and amount of white on the crissum (Snow 1985, O'Neill et al. 2011).Our specimen, however, has all features (described above) attributed to a typical T. hauxwelli.The specimen (Fig. 2) also differs from specimens of T. sanchezorum, which have a distinct olive bill with yellow tomia (instead of dark brown), yellow-orange bare orbital ring (feathered in T. hauxwelli), more contrastingly dark throat streaks on a whiter background and grayish-brown tail (instead of rufous-brown) (O'Neill et al. 2011).Therefore, the individual collected is in full agreement with external morphology of other specimens of T. hauxwelli examined.Some of the specimens used to validate the identity of the species are given in Table 1.
The specimen is an adult male (testes 10 and 9 mm), 61 g, 230 mm of total length, 380 mm of wingspan, brown iris, total dark brown bill, dark gray tarsus, light gray foot palm, no brood patch, molt or parasites.

Discussion
Despite the efforts of some important historical naturalists such as Emmet R. Blake, Olivério Pinto, José Hidasi (Pinto 1932, Pinto 1940, Tubelis and Thomas 2003, Straube 2011, Nunes et al. 2013), and recent researchers, who catalogued 413 species of birds occurring at Serra de Maracajú (Nunes et al. 2013), this is the first record of T. hauxwelli for the state of Mato Grosso do Sul.Furthermore, this is the southernmost record that significantly extends the distribution limits of this species.This new record is approximately 616 km from the closest location where a specimen was collected (AMNH 833476, Velasco province, Santa Cruz department, Bolivia, 16°33ʹ00ʺ S, 059°39ʹ00ʺ W) and roughly 472 km from the closest visual/vocal record (photo records: WA1178388, WA1178389; vocal records: WA1156136, WA185399, WA1179314; Santo Antônio do Leverger, Mato Grosso, Brazil, 15°51ʹ55.3ʺS, 056°04ʹ54.7ʺW).Our record shows that this species is not restricted to humid and dense Amazonian forests (Snow 1985, Ridgely and Tudor 2009, Collar 2016) but rather shows that it can occupy drier environmental conditions, such as some Cerrado forests.On the other hand, because the area is influenced by other biomes, such as the Amazon and Chaco, this area might represent a more suitable habitat for this Amazonian bird species.Considering that T. hauxwelli is presumably sedentary (Collar 2016), it is likely that this individual represents a resident population at the region.Further searches may show if this species is present at nearby localities at a similar latitude and between the new locality and previously known occurrences.