Scytalopus griseicollis morenoi Avendano & Donegan, 2015

Avendano, Jorge Enrique & Donegan, Thomas M., 2015, A distinctive new subspecies of Scytalopus griseicollis (Aves, Passeriformes, Rhinocryptidae) from the northern Eastern Cordillera of Colombia and Venezuela, ZooKeys 506, pp. 137-153 : 139-145

Scytalopus griseicollis morenoi Avendano & Donegan ssp. n.

Holotype.

An adult male study skin specimen (Figs 1 and 3), no. 37538 of the ornithological collection of the Instituto de Ciencias Naturales (ICN), Universidad Nacional de Colombia, Bogotá. Tissue samples (pectoral muscle) are deposited at the Banco de Tejidos of Universidad de los Andes (ANDES-BT 1567), Bogotá. The specimen and tissue samples relate to the same individual organism which was collected and prepared on 2 August 2009 by J. E. Avendaño (original field no. JEA 811) in secondary growth / forest ecotone at La Pica, finca La Rinconada, vereda Potrero de Rodríguez, municipality of Molagavita, Santander department, Colombia (06°43'N; 72°47'W; 2880 m).

Diagnosis.

Scytalopus griseicollis morenoi exhibits all the characteristics of the genus Scytalopus ( Ridgway 1911, Krabbe and Schulenberg 1997, Cuervo et al. 2005). It appears to be most closely related to Scytalopus griseicollis on account of its rather grey plumage, orange-rufous vent (Fig. 1) and similar vocalisations (Figs 4 - 5). Scytalopus griseicollis morenoi is distinguishable from Scytalopus perijanus from the Serranía de Perijá by its entirely brown nape and back (Fig. 1) and distinct vocalisations ( Avendaño et al. 2015). It is diagnosable from Scytalopus griseicollis griseicollis of the Altiplano Cundiboyacense and Scytalopus griseicollis gilesi of the Serranía de los Yariguíes by its brown (not grey) mantle, tail, wing coverts and nape (Fig. 1). Juveniles of the new subspecies differ mainly from the nominate and Scytalopus griseicollis gilesi in having darker base plumage ventrally (which is scalloped white) whereas they are dorsally darker than the nominate, like in Scytalopus griseicollis gilesi (Fig. 2). These characters also distinguish juveniles of the new subspecies from those of Scytalopus perijanus , which are more yellowish ventrally. It also has a shorter tail than Scytalopus griseicollis gilesi (see Appendices 2 and 4 in Donegan and Avendaño (2008)). It has an on average higher pitched scold than Scytalopus griseicollis griseicollis but this is not diagnostic. Compared to Scytalopus griseicollis gilesi , the new subspecies has a faster and higher frequency song and higher frequency scold (in the latter case, with no overlap) (Figs 4 - 5; and Appendices 3-4 in Donegan and Avendaño (2008)).

Description of the holotype.

Lores, forehead, crown, auriculars and neck sides Dark Neutral Gray 83; nape, scapulars, mantle, rump, tail and upper-tail coverts between Verona Brown 223B and Amber 36, the latter barred with Sepia 219. Underparts Medium Neutral Gray 84, becoming slightly lighter (Light Neutral Gray 85) on the center of belly; flanks, lower belly, thighs and under-tail coverts between Buff 24 and Tawny 38, the latter barred with Sepia 29. Wing coverts Dark Neutral Gray 83 fading to Dark Brownish Olive 129 and tipped with Verona Brown 223B; remiges and tertials Dark Grayish Brown 20 with external margin Cinnamon-Rufous 40, and the latter tipped Tawny 38, with dark (Sepia 119) subterminal bar. Light molt in mantle, throat, breast and abdomen. 10 rectrices. Measurements (in mm): wing flat 56.0, tail 41.1, tarsus 20.5, total culmen 13.2, exposed culmen 9.9. Mass 17.0 g. During preparation and dissection, the following features were noted, none of which is evident from the holotype itself: some subcutaneous fat in furcula and neck; testes rather enlarged (left testis: 5.3 × 2.5 mm; right testis 4.8 × 3.0 mm); stomach contained insect remains. Soft parts in life (not coded for colours in the field): bill dark ( ‘horn’), lighter on the base of the lower mandible; iris dark brown; tarsus and feet light brown, claws whitish, hallux blackish, soles pale yellow.

Paratypes.

The type series includes the following specimens in museums which we have been able to compare directly with fresh specimens collected as part of this study. The specimens showed in Figures 2 - 3 are denoted with an asterisk. (1) Adult male (ICN 37548*) collected at the type locality on 4 August 2009; (2) adult male (ICN 37514*) collected at 2700 m elevation above finca La Paterna, vereda San Isidro, corregimiento of Pangote, municipality of San Andrés, Santander department, on 28 July 2009; (3) adult male (ICN 37570*) collected at 2800 m elevation at finca El Tablón, vereda Santa Cruz, municipality of San Andrés, Santander department, on 14 September 2009; (4) adult male (ICN 36121) collected at 2950 m elevation at El Gritadero, vereda El Monsalve, municipality of Suratá, Santander department, on 19 August 2006; (5) adult male (ICN 36416) collected at 3100 m elevation at finca Ramírez, vereda Parra Juan Rodríguez, municipality of Piedecuesta, Santander department, on 11 July 2007; (6) adult female (ICN 37516*) collected at 2725 m elevation at La Corcova, vereda San Isidro, municipality of San Andrés, Santander department, on 28 July 2009; (7) adult female (ICN 37522) collected at 2950 m elevation below Pozo El Indio, La Pica, finca La Rinconada, Vereda Potrero de Rodríguez, municipality of Molagavita, Santander department, on 30 July 2009; (8) fledgling male (IAvH-A 14948*) collected at 2800 m elevation by S. Sierra at Alto El Pesebre, Sector Orocué, Tamá NP, municipality of Herrán, Norte de Santander department, on 18 September 2008; (9) unsexed fledgling (MLS 3993*) collected by Hno. Nicéforo María at Fontibón, municipality of Pamplona, Norte de Santander, on 30 April 1941. Specimens 1 to 7 were collected and prepared by J. E. Avendaño under original field numbers JEA-821, 787, 916, 323, 499, 789 and 795, respectively. See further Suppl. material 1.

Etymology.

The new subspecies name honours the late Nelson Moreno Rodríguez, co-founder and curator of the Museo de Historia Natural of the Universidad Industrial de Santander. He was a mentor and friend of the first author and an enthusiastic naturalist. This name also recognizes his contributions to ornithology, natural history and education in the department of Santander. The name is formed from a fictional masculine Latin noun “morenous”, in the genitive singular. The name is non-variable.

Remarks.

Variation in the type series. Plumage variation in the type series is slight and mainly concentrated in the colour tone of the nape, back and underparts (Fig. 3). Males ICN 37548 and 37570 have paler underparts (Pale Neutral Gray 86), the former with a whitish tinge in the center of the belly; both specimens have flanks, lower belly, thighs and under-tail coverts more tawny than the holotype. Male ICN 37514 is slightly paler on the belly. Some males (e.g. ICN 37514, 37548 and 37570) are duller (less Amber 36) than the holotype and show some grey (Dark Neutral Gray 83) feathers in the nape and mantle. Both females at ICN are ventrally similar to the holotype, but ICN 37516 has a tinge of Pale Pinkish Buff 121D in the belly. Nape and back coloration differs from the holotype as in males ICN 37514, 37548 and 37570. Juvenile specimens, such as MLS 3993 and IAVH-A 14948, have very dark brown base coloration with narrow, scallopped whitish markings on the trailing edges of all head, underparts, dorsal and wing covert feathers (Fig. 2). Details on vocal and biometric variation are presented in the appendices to Donegan and Avendaño (2008).

Additional specimens examined.

We examined 42 additional specimens we identified as Scytalopus griseicollis morenoi (Suppl. material 1). All these specimens exhibit variation within the range described above for the type series.

Distribution.

Scytalopus griseicollis morenoi is endemic to the northern Eastern Cordillera in Colombia and Venezuela, ranging from La Palmita in Norte de Santander, south to Molagavita in Santander, and covering an altitudinal range between 2000 m and 3900 m (Suppl. materials 1-2; Participantes de la Alianza Biomap 2014). Our niche model suggests that Scytalopus griseicollis morenoi is present on both slopes of the northern section of the Eastern Cordillera, largely in more humid montane slopes and subpáramo to páramo habitats (Fig. 6). Range limits in Scytalopus griseicollis ' subspecies seem to correspond to several geographic barriers and changes in environmental conditions across the northern Eastern Cordillera ( Graham et al. 2010). Northern distributional limit of Scytalopus griseicollis morenoi seems to concur with the Ocaña ( Serranía de los Motilones) depression (c. 1200 m). Its distribution to the north-east is restricted by the Táchira depression, despite our niche model predicting some suitable habitat in the southern Mérida Cordillera (Fig. 6). The vocally distinctive and ecologically less specialised Scytalopus meridanus replaces the species in the Venezuelan Andes ( Donegan and Avendaño 2008, Hilty 2003). These barriers prevent contact of a high elevation specialist with poor dispersal abilities, such as this, with Scytalopus perijanus of the Serranía de Perijá and Scytalopus meridanus of the Mérida Cordillera, respectively. On the east slope of the Eastern Cordillera, the distribution of Scytalopus griseicollis morenoi seems to be restricted to the Tamá-Sierra Nevada del Cocuy foothills. This region appears to constitute the northern or southern distribution limit of many montane species and subspecies on the east slope of the Eastern Cordillera ( Hilty and Brown 1986, Restall et al. 2006).

To the south, Scytalopus griseicollis morenoi 's potential habitat becomes reduced and discontinuous, possibly related with an environmental break at the head of the arid Chicamocha valley in the Santander-Boyacá departments boundary, which precludes any potential contact with the nominate form of the Altiplano Cundiboyacense. The headwaters of the arid Chicamocha valley represent the northern or southern distributional limit of several montante and páramo species ranging along the west slope of the Cordillera or represent internal breaks of widely distributed species ( Hilty and Brown 1986, Graham et al. 2010). Likewise, the new subspecies is isolated from Scytalopus griseicollis gilesi by a depression at the headwaters of the rivers Horta and Opón, which connects the Serranía de Yariguíes with the rest of the Eastern cordillera (c. 1450 m).

Ecology.

A typical dweller of the understory of elfin forest, páramo and rarely montane and oak forest, although it also can be found at forest borders and bushes. Individuals, possibly young birds were occasionally observed crossing small pastures and trails between patches of more appropriate habitat. Scytalopus griseicollis morenoi has been recorded as fairly common to common at several localities in Santander with 2-4 individuals recorded in 1 ha study sites (J.E.A. pers. obs.). Breeding and reproduction may take place during the second half of the year. Fledglings have been collected at Tamá National Park on 27 June 1999 (IAvH-A 10664) and 3 September 2008 (IAvH-A 14948). In the municipality of Piedecuesta, Santander, a fledgling was collected at Hacienda Las Vegas on 23 September 1949 (USNM 411791) and another was seen at at Finca Ramírez, vereda Parra Juan Rodríguez, on 13 July 2007 (J.E.A. pers. obs.). A similar periodicity for breeding has been recorded in Scytalopus griseicollis gilesi (fledgling on 24 June 2008, ICN 35610) and Scytalopus griseicollis griseicollis (nestlings and fledglings from June to December, ICN 35441, 36997, 38528, 38529, 373416, IAvH 10305, 12701, 13935, USNM 373416). Breeding periods in Scytalopus griseicollis throughout its range could be triggered by the timing of rainy seasons, which present two peaks in the Eastern Cordillera (April-May and September-November) ( Morales et al. 2007).

Conservation.

Scytalopus griseicollis is a range-restricted species mainly associated with patchy cloud forest and páramo of the northern Eastern Cordillera. A scenario of deforestation and habitat fragmentation affects the subpáramo-páramo belt of the entire Colombian Andes ( Van der Hammen 2002). The west slope of the Eastern Cordillera, where most of the potentially suitable habitat for Scytalopus griseicollis morenoi is found, represents the second most deforested cloud forest region in the Colombian Andes, with only small and more isolated fragments remaining ( Morales-R and Armenteras-Pascual 2013). An unexpected small scale forest recovery was observed in the northern Andes (Eastern and Central Cordilleras) between 2001 and 2010, although this may have been influenced by the then prevailing security situation. Any increase in northern Andean Páramo has been slight and may have been wholly offset by expansion of potato plantations in the departments of Boyacá and Santander ( Sánchez-Cuervo et al. 2012). Moreover, projected climate change is modelled to be particularly acute for higher elevations of the northern Eastern Cordillera in future ( Velásquez-Tibata et al. 2012). The new subspecies occurs in few protected areas that have a broad elevational range (which might mitigate such threats). Scytalopus griseicollis morenoi , and the species as a whole, have doubtless suffered a significant reduction of potential area of occupancy as a result of man’s influence on the habitats of the Eastern Cordillera. The largest national park established to protect East Andean montane forests, in Serranía de los Yariguíes, does not protect the new subspecies - which is replaced there by Scytalopus griseicollis gilesi . Opportunities to expand other protected areas in the main East Andean range and to promote habitat connectivity in the region would be welcome ( Sánchez-Cuervo et al. 2012). Several protected areas in the northern Eastern Cordillera, such as the Tamá binational National Park and the Páramo de Santurbán and Bosques Andinos Húmedos El Rasgón Regional Parks could harbour important populations of this subspecies. However, even these protected areas are threatened by a lack of on-the-ground protection measures or park staff and mining proposals.

This subspecies is locally abundant in well conserved high-Andean forests and páramos (Stiles and Rosselli 1998, Donegan and Avendaño 2008), and even in small and fragmented patches of habitat ( Echeverry-Galvis and Morales-Rozo 2007, Peraza 2011), which suggests that local populations could resist extinction if some vegetation cover and connectivity is maintained. Further studies of the forests and organisms of the northern Eastern Cordillera are needed to clarify the potential ecological/geographic barriers which isolate different distinctive subspecies of the region ( Avendaño et al. 2013) and to establish conservation priorities.