Catharus opertaneus Wetmore 1955

Halley, Maưhew R., Catanach, Therese A., Klicka, John & Weckstein, Jason D., 2023, Integrative taxonomy reveals hidden diversity in the Catharus fuscater (Passeriformes: Turdidae) complex in Central and South America, Zoological Journal of the Linnean Society 199 (1), pp. 228-262 : 255-257

Catharus opertaneus Wetmore 1955

Antioquia nightingale-thrush

( Figs 15 , 16 19 )

Catharus fuscater opertaneus Wetmore 1955: 46 ; Deignan 1961: 430; Meyer de Schauensee 1964: 317; Hilty and Brown 1986: 543; Fjeldså and Krabbe 1990: 554; Clement 2000: 299; Collar 2005: 700; Acevedo-Charry 2014; Halley 2020; Halley 2021.

Catharus fuscater Meyer de Schauensee 1966: 412 (in part); Meyer de Schauensee 1970: 342 (in part); Hilty and Brown 1986 (in part); Ridgley and Tudor 1989: 110 (in part); Beltrán and Kattan 2001; Krabbe et al. 2006; Cuervo et al. 2008; Molina Martinez 2014; Greeney et al. 2015; Dyrcz et al. 2015; Remsen et al. 2023 (in part).

Catharus fuscater fuscater Ridgley and Greenfield 2001: 660 (in part); LeCroy 2005: 38.

Catharus opertaneus tenebris ssp. nov. (formerly Undescribed 2).

urn:lsid:zoobank.org:act:B1F7F134-2EB8-4FB9-A1EB-31E2CC7AB4D7 .

Catharus fuscater Parker et al. 1985: 192 196; Rasmussen et al. 1996: 40.

Catharus fuscater fuscater Clement 2000: 299 .

Catharus fuscater caniceps M.B. Robbins in Ridgley and Greenfield 2001: 660.

‘Unnamed-2’ Halley 2021: 133.

Type material

Catharus o. opertaneus : USNM 427029 (holotype), study skin, adult male, collected by M.A. Carriker Jr. at ‘ Haciendo Potreros’ (1981 m elev.), ‘on the Río Herradura , 15 miles south-west of Frontino’, Antioquia, Colombia (approximately 6.39°, –76.09°; see: Paynter 1997: 190) on 10 June 1950 (Wetmore 1955, Deignan 1961: 430) . USNM 436771 (paratype), study skin, collected by Carriker on the Río Urrao , Antioquia, on 14 September 1951 . Both specimens were examined by M. R.H. on 23 October 2013 .

Catharus o. tenebris ssp. nov.: ANSP 185734 (holotype), study skin, adult female, collected and prepared by T. J. Davis in humid montane forest on the eastern slope of Cordillera de las Lagunillas , north bank of Río Isimanchi, about 6 km north-west of San Andrés, Zamora-Chinchipe, Ecuador (–4.7833°, –79.3333°, elev. 2250 m), on 6 November 1992. When it was prepared, the holotype weighed 35 g with no bursa and an ovary that measured 8 × 4 mm. Neither the ova nor the oviduct were enlarged, the skull was 50% pneumatized, and there were insect remains in the stomach. In 2022, the crown of ANSP 185734 was slightly darker than Sepia (219), transitioning to a darker version of Hair Brown (119A) on the back and rump. The undertail coverts were Dark Drab (119B) and the flanks were darker and cooler than Vandyke Brown (121). The breast was Greyish Horn Colour (91) with faint vertical striations. The throat was Drab-Grey (119D), contrasting with the breast, and a dark brown line connected the malar regions across the chin. No moult was noted. Iris colour was recorded as ‘grey’ and there is a pencilled note by M.B. Robbins ( MBR): ‘ Catharus fuscater caniceps ? 2 other adults at this locality [ KU 186025 and ANSP 186025 , both males] had greyish irides; M.B. R. ‘93. [and] 1 in MECN [Museo Ecuatoriano de Ciencias Naturales], Quito’. The maxilla was ‘black’ when the specimen was prepared, and it remains so ( Table 4 ). The mandible and gape were ‘dull orange’ in life, the eye-ring was ‘orange’, and the feet were ‘yellowish brown’.

Geographic range

Catharus o. opertaneus : In Colombia, occurs on the western slope of the Western Andes near Frontino and Urrao (Antioquia), at 1980 and 2730 m, respectively (Wetmore 1955), in the Central Andes near the cities of Pereira (Risaralda) and Manizales (Caldas) between 2400 and 2600 m ( Beltrán and Kattan 2001), and at several other sites in Antioquia and Caldas ( Cuervo et al. 2008) and Tolima (Molina Martinez 2014). In Ecuador, occurs at Yanyacu Biological Station near Cosanga, Napo province ( Dyrcz et al. 2015, Greeney et al. 2015). If intervening populations between north-eastern Ecuador (Sucumbios) and northern Colombia (Antioquia) are of the same species, as we hypothesize, then two specimens collected by Carriker near Popayán, Cauca, Colombia, in 1959 and 1960 are probably C. opertaneus (WFVZ 16446, 16447).

Catharus o. tenebris ssp. nov.: Restricted to the Río Chinchipe watershed of northern Peru and south-eastern Ecuador, south of the Río Zamora.

Adult specimens examined

Catharus o. opertaneus (N = 2): Colombia (N = 2): Antioquia (one male, one female): Heda Potreros, 15 miles south-west of Frontino: USNM 427029 (male); Heda la Ilusion , Río Urrao : USNM 436771 (female) .

Catharus o. tenebris ssp.nov.(N = 4): Ecuador (N = 1): Zamora-Chinchipe (one female): Cordillera de las Lagunillas, 6 km north of San Andrés : ANSP 185734 (female). Peru (N = 3): Piura (two males, one female): Playón: LSUMZ 88629 (male); ‘Machete’, on the Zapalache-Carmen Trail: LSUMZ 97810 (male); ‘Batán’, on the Zapalache-Carmen Trail: LSUMZ 97809 (female).

Immature specimens examined

Catharus o. opertaneus (N = 1): Ecuador (N = 1): Napo (1 male): Puente del Rio Quijos: AMNH 180631 (male) .

Catharus o. tenebris ssp. nov. (N = 0).

Audio recordings examined

Catharus o. opertaneus (N = 12): Colombia (N = 7): Antioquia: Reserva Natural Cañón Del Río Claro : ML 101421201 ; Caldas: Reserva Ecológica Río Blanco: ML 101421201 , 177887161 , XC 440235 ; Risaralda: Santuario de Fauna y Flora Otún Quimbaya: ML 127271981 , XC 102252 ; Tolima: La Plata, Cañón del Combeima : ML 345974171 . Ecuador (N = 5): Napo: Cabañas San Isidro: ML 133453931 ; Cordillera Guacamayos: ML 142031581 ; Unknown locality: XC 255039; Volcán Sumaco :XC 443582 ; Sucumbíos: Lumbaquí, Gonzalo Pizarro : XC 529000 .

Catharus o. tenebris ssp. nov. (N = 4): Ecuador (N = 4): Zamora-Chinchipe: Old Loja-Zamora Rd. : ML 318532061 ; Parque Nacional Podocarpus: XC 460029; Reserva Tapichalaca: XC 250592, 250647 .

Diagnosis

Genetics: In the UCE tree, samples from the ranges of C. o. opertaneus and C. o. tenebris ssp. nov. formed reciprocally monophyletic clades, and together they formed a clade that was sister to the clade consisting of C. b. berlepschi + C. b. nebulus ssp. nov.. In the ND2 tree, C. o. opertaneus was sister to the Darién clade ( C. mirabilis + C. arcanus sp. nov.), with an estimated divergence of 2.5 Mya (95% HPD = 1.9–3.0), and C. o. tenebris ssp. nov. was sister to C. b. berlepschi , with a divergence estimate of 0.4 Mya (95% HPD = 0.2–0.5). ABGD and ASAP analyses of ND2 data both identified C. o. opertaneus and C. o. tenebris spp. nov. as unique genetic clusters (uncorrected p -distance = 0.07), supporting the formal taxonomic recognition of both.

Morphology: Catharus opertaneus is sexually monochromatic with dark ‘olive brown’ dorsal plumage, unlike any other taxon in the complex (Wetmore 1955; photos in: Beltrán and Kattan 2001, Dyrcz et al. 2015). It was the only taxon with no difference between the sexes in the colour of the maxilla (i.e. both completely black). M.R.H. examined the C. o. opertaneus type in 2015, but lacked specimens for the standardized colour comparison. In comparisons between C. o. tenebris ssp. nov. and the rest of the complex, the closest match in colour was the C. [f.] mentalis adult female, which nevertheless had a darker throat than C. o. tenebris ssp. nov. ( Figs 15–17 ; Table 3 ). We were unable to determine whether C. o. opertaneus and C. o. tenebris ssp. nov. differ in plumage colour ( Table 3 ), but note that skins of C. o. tenebris ssp. nov. had paler irides (e.g. ‘grey’ ANSP 185734 female, ‘grey brown’ LSUMZ 97809 female, ‘olive-brown’ LSUMZ 88629 male) and ‘orange’ orbital skin (ANSP 185734, LSUMZ 88629, 97809), whereas C. o. opertaneus is said to have ‘dark, cinnamon-brown’ irides and yellow orbital skin, in both northern (Colombian) and southern (Ecuadorean) populations (see photos in: Beltrán and Kattan 2001, Dyrcz et al. 2015).

Voice: Catharus opertaneus (sensu lato) was distinguished from all taxa, except C. b. nebulus ssp. nov. and C. [f.] mentalis , by its Type 3 (‘short/simple’) punctuation calls ( Fig. 9 ). Too few recordings of song were available to assess the divergence of C. opertaneus from other taxa in the complex. Of the four triadic contours detected in C. o. opertaneus (ABC, ACB, CAB, CBA), only one (ABC) was shared with C. o. tenebris ssp. nov.. Of the four tetradic contours detected in C. o. opertaneus (ABCD, CDAB, CDBA, DCBA), only one (CDAB) was shared with C. o. tenebris ssp. nov.. An aberrant recording of C. o. opertaneus from Sucumbios, Ecuador (XC 529000) contained a unique triadic song type in which the upper two notes were rapidly trilled before descending to a lower note (i.e. a combination of contours BCA and CBA), unlike any other song in our dataset.

Comments

Based on geography, we inferred that intervening populations in the Central Andes, between Sucumbios (ZMUC 119587) and Antioquia (ZMUC 134855), belong to the same clade ( C. opertaneus ). We hypothesize that the placement of C. opertaneus in the ND2 tree, as sister to the Darién clade with relatively low support, may be evidence of ancient episodes of hybridization and mitochondrial capture between those taxa (see: Toews and Brelsford 2012). Greeney et al. (2015) documented cooperative breeding in C. o. opertaneus in the Ecuadorean population (i.e. five adults provisioning young in a single nest), the first report of this behaviour in a resident Neotropical Catharus species. Previously, this rare behaviour was known only in Bicknell’s thrush ( C. bicknelli, Goetz et al. 2003 ) and Veery ( C. fuscescens, Halley and Heckscher 2012 , Halley 2014, Halley et al. 2016).

Etymology

The proposed English name references Antioquia, Colombia, where the types were collected. The scientific name C. o. tenebris ssp. nov. is derived from the feminine Latin noun tenebrae (darkness), referring to the dark forest habitat of the taxon .

Figures

Figure 9. Taxonomic variation in the structure of ‘punctuation calls’, visualized in RavenPro 1.5 (Cornell University). We recognize three groups based on shared acoustic structure: (Type 1) pulsed/rippling:C. [f.] hellmayri, Undescribed 1, C. [f.] mirabilis; (Type 2) long/sinuous: C. [f.] sanctaemartae, C. [f.] fuscater, C. [f.] berplepschi; (Type 3) short/simple: Undescribed 2, C. [f.] opertaneus, Undescribed 3, C. [f.] mentalis.

Figure 15. Ventral and dorsal views of the adult male plumages in C. b. berlepschi, C. b. caniceps, C. o.tenebris ssp. nov., C. b. nebulus ssp.nov., and C. mentalis. Photograph by M.R.H.

Figure 16. Ventral and dorsal views of the adult female plumages in C. b. berlepschi, C. b. caniceps, C. o.tenebris ssp. nov., C. b. nebulus ssp.nov., and C. mentalis. Photograph by M.R.H.

Figure 17. Side view of adult plumages in C. b. nebulus ssp. nov. Photograph by M.R.H.

Figure 18. Ventral and dorsal views of juvenile plumages in C. hellmayri, C. b. nebulus ssp.nov., and C. b. berlepschi. Photograph by M.R.H.

Figure 19. Side view of adult plumages in C. o. tenebris ssp.nov. Photograph by M.R.H.