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Phenotypic and genetic analysis support distinct species status of the Red-backed Woodpecker (Lesser Sri Lanka Flameback: Dinopium psarodes) of Sri Lanka


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Hybridization has challenged taxonomy, since hybridizing forms could be stable evolutionary entities or ephemeral forms that are blending together. The island of Sri Lanka has 2 subspecies of the flameback woodpecker D. benghalense: D. b. jaffnense in the north and D. b. psarodes in the south. Red plumage separates the endemic phenotype D. b. psarodes from other subspecies of D. benghalense. Despite these differences, intermediate phenotypes in north-central Sri Lanka discouraged the elevation of D. b. psarodes into a full species. The recent HBW and BirdLife International checklist, however, has elevated D. b. psarodes to a full species (D. psarodes), primarily based on its plumage. To objectively evaluate whether this taxonomic elevation is warranted, we examined the phenotypic and genetic affinities of D. psarodes within the D. benghalense cluster. In doing that we provide the first quantitative phenotypic and genetic analysis across a hybrid zone for an Old World woodpecker group. We sampled woodpeckers along a line transect across the island and measured body shape/size, plumage, and genetic variation in a mitochondrial gene (Cytb). Plumage color ranged from red in the south to yellow in the north, with varying proportions of orange in north-central Sri Lanka (an area of ~66 km). Morphology (body shape/ size) and plumage characters showed a clear separation. There are 2 mitochondrial haplotype groups, one in the north and one in the south. A mixture of north and south haplotypes were seen in north-central Sri Lanka. Width of the hybrid zone suggests that some form of selection limits the spread of hybrids into the range of parental forms. Morphological, plumage, and genetic traits are all indicative of limited hybridization in a narrow zone between the 2 taxa, supporting the treatment of D. psarodes as a distinct species. This study provides an illustrative example of extensive hybridization between stable taxonomic entities, discouraging the practice of merging hybridizing forms as single species.
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Volume 133, 2016, pp. 497–511
DOI: 10.1642/AUK-15-233.1
Phenotypic and genetic analysis support distinct species status of the
Red-backed Woodpecker (Lesser Sri Lanka Flameback: Dinopium
psarodes) of Sri Lanka
Saminda P. Fernando,
Darren E. Irwin,
and Sampath S. Seneviratne
Avian Evolution Node, Department of Zoology, University of Colombo, Colombo, Sri Lanka
Biodiversity Research Centre & Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
* Corresponding author:
Submitted December 20, 2015; Accepted March 23, 2016; Published June 22, 2016
Hybridization has challenged taxonomy, since hybridizing forms could be stable evolutionary entities or ephemeral
forms that are blending together. The island of Sri Lanka has 2 subspecies of the flameback woodpecker D.
benghalense:D. b. jaffnense in the north and D. b. psarodes in the south. Red plumage separates the endemic
phenotype D. b. psarodes from other subspecies of D. benghalense. Despite these differences, intermediate
phenotypes in north-central Sri Lanka discouraged the elevation of D. b. psarodes into a full species. The recent
HBW and BirdLife International checklist, however, has elevated D. b. psarodes to a full species (D. psarodes),
primarily based on its plumage. To objectively evaluate whether this taxonomic elevation is warranted, we
examined the phenotypic and genetic affinities of D. psarodes within the D. benghalense cluster. In doing that we
provide the first quantitative phenotypic and genetic analysis across a hybrid zone for an Old World woodpecker
group. We sampled woodpeckers along a line transect across the island and measured body shape/size, plumage,
and genetic variation in a mitochondrial gene (Cytb). Plumage color ranged from red in the south to yellow in the
north, with varying proportions of orange in north-central Sri Lanka (an area of ~66 km). Morphology (body shape/
size) and plumage characters showed a clear separation. There are 2 mitochondrial haplotype groups, one in the
north and one in the south. A mixture of north and south haplotypes were seen in north-central Sri Lanka. Width of
the hybrid zone suggests that some form of selection limits the spread of hybrids into the range of parental forms.
Morphological, plumage, and genetic traits are all indicative of limited hybridization in a narrow zone between the
2 taxa, supporting the treatment of D. psarodes as a distinct species. This study provides an illustrative example of
extensive hybridization between stable taxonomic entities, discouraging the practice of merging hybridizing forms
as single species.
Keywords: Dinopium benghalense, island endemicity, flameback woodpeckers, hybridization, hybrid zone,
speciation, Sri Lanka
´lisis fenot´
ıpicos y gen ´
eticos apoyan el estatus de especie de Dinopium psarodes en Sri Lanka
La hibridaci ´
on es desafiante para la taxonom´
ıa puesto que las formas que hibridan pueden ser entidades
evolutivamente estables o formas ef´
ımeras que se esta
´n mezclando. La isla de Sri Lanka tiene dos subespecies de
Dinopium benghalense;D. b. jaffnense en el norte y D. b. psarodes en el sur. El plumaje rojo separa el fenotipo end ´
de D. b. psarodes del de otras subespecies de D. benghalense. A pesar de estas diferencias, la existencia de fenotipos
intermedios en el centro-norte de Sri Lanka previno la elevaci ´
on de D. b. psarodes al estatus de especie. Sin embargo, la
lista ma
´s reciente del Handbook of Birds of the World y Birdlife International elev ´
oaD. b. psarodes al rango de especie
(D. psarodes) basa
´ndose principalmente en el plumaje. Para evaluar objetivamente si se justifica este cambio
taxon ´
omico, examinamos las afinidades gen´
eticas y fenot´
ıpicas de D. psarodes en el grupo de D. benghalense.Al
hacerlo, presentamos el primer ana
´lisis cuantitativo fenot´
ıpico y gen´
etico a trav´
es de una zona de hibridaci ´
on de un
carpintero del viejo mundo. Muestreamos carpinteros a lo largo de un transecto que atravesaba la isla y medimos el
tama ˜
no y la forma del cuerpo, el plumaje y la variaci ´
on gen´
etica en un gen mitocondrial (Cytb). El color del plumaje
vari ´
o de rojo en el sur a amarillo en el norte, con naranja en diferentes proporciones en el centro-norte de Sri Lanka (un
´rea de ~66 km). Los caracteres morfol ´
ogicos (tama ˜
no y forma del cuerpo) y del plumaje mostraron una separaci ´
clara. Existen dos grupos de haplotipos mitocondriales, uno en el norte y otro en el sur. Se vio una mezcla de
haplotipos del norte y del sur en el centro-norte de Sri Lanka. El ancho de la zona de hibridaci ´
on sugiere que alguna
forma de selecci ´
on limita la dispersi ´
on de los h´
ıbridos hacia la zona de distribuci ´
on de las formas parentales. Todos los
rasgos morfol ´
ogicos, gen´
eticos y del plumaje indican que existe hibridaci ´
on limitada entre los dos taxones en una
Q2016 American Ornithologists’ Union. ISSN 0004-8038, electronic ISSN 1938-4254
Direct all requests to reproduce journal content to the Central Ornithology Publication Office at
zona estrecha, lo que apoya el estatus de especie de D. psarodes. Este estudio presenta un ejemplo ilustrativo de
hibridaci ´
on extensa entre entidades taxon ´
omicas estables, lo que desaconseja la pra
´ctica de unir formas que hibridan
en una sola especie.
Palabras clave: Dinopium benghalense,end
emicos de islas, especiaci ´
on, hibridaci ´
on, Sri Lanka, zona h´
The woodpecker genus Dinopium has historically consist-
ed of 5 species from South and Southeast Asia, namely
Dinopium rattlesii,D. shorii,D. javanense,D. everetti,and
D. benghalense (Winkler et al. 1995, Winkler and Christie
2002, Clements et al. 2012). They are commonly called
flamebacks due to their golden-colored mantle, scapulars,
and folded wings. Among Dinopium, D. benghalense
consists of 6 subspecies or races, distributed across South
Asia (Gill and Donsker 2014), with 2 in Sri Lanka: D. b.
jaffnense (Golden-backed Woodpecker) in the north and
D. b. psarodes (Red-backed Woodpecker) in the south
(Rasmussen and Anderton 2012, Gorman 2014). Many
color variations have been observed within the Sri Lankan
forms (e.g., Legge 1880, Baker 1927, Wait 1931, Whister
1944, Philips 1953, Henry 1971, Rasmussen and Anderton
2012, Lamsfuss 2013, Gorman 2014, Fernando and
Seneviratne 2015, Freed et al. 2015).
The red-backed form of the Dinopium complex had
long been considered as endemic to Sri Lanka. Layard
(1853) classified the red-backed form as Brachypternus
ceylonus and the golden-backed form (D. b. jaffnense)asB.
aurantius. Legge (1880) reported the Red-backed Wood-
pecker B. ceylonus as an endemic species to Sri Lanka.
Both Legge (1880) and Wait (1931) commented on the
possible hybridization of the 2 island forms. Intermediate
phenotypes of Dinopium were reported as far back as
1868–1877 (Legge 1880). As a result, after Wait (1931), all
authors except del Hoyo et al. (2014) continued to adopt
the same taxonomic treatment of the 2 Sri Lankan forms
as members of D. benghalense (Baker 1927, Whistler 1944,
Ripley 1946, Ripley 1949, Philips 1953, Ali and Ripley 1983,
Ripley and Beehler 1990, Rasmussen and Anderton 2012).
The recent checklist of Birdlife International (del Hoyo
et al. 2014) elevated D. b. psarodes to a full species based
on a system proposed by Tobias et al. (2010). In this
system, a taxon is considered a separate species if an
overall differentiation score reaches 7. The overall score is
a sum of 2 elements: the quantification of differentiation in
3 main traits (morphology, voice, and biometrics) and 1
subsidiary trait (ecology and behavior), and the quantifi-
cation of geographical relationship (allopatry or parapatry
and the nature of the hybrid zone). In elevating the
subspecies D. b. psarodes into a full species, del Hoyo et al.
(2014) used the differences in its coloration (shining scarlet
on back shading to dull red on wings, lack of black in
carpal area), measurements (longer bill, wings, and tail)
and vocalization (louder and higher-pitched call) com-
pared to D. b. jaffnense.
Based on observations of plumage of Dinopium in the
wild, a recent paper (Freed et al. 2015) has described 8
intermediate plumage types, and assumed that these types
are of hybrid origin. Furthermore, Freed et al. (2015)
showed that these intermediate types are found in the
north-central part of the island. However, a quantitative
analysis of these different plumage patterns in the Dinopium
complex has not been attempted. Here we provide the first
comprehensive examination of phenotypic (body shape/size
and plumage) and genotypic variation across the 2 taxa of
the Dinopium benghalense complex in the island to
determine how well the criteria proposed by Tobias et al.
(2010) for avian taxonomy apply to this species complex
and to shed light on the complex biogeographic patterns
displayed in Dinopium in the South Asian region (de Silva et
al. 2014). We hypothesized that (1) D. psarodes is genetically
differentiated from the D. benghalense cluster in a way
corresponding to their phenotypic difference; (2) hybridiza-
tion occurs in the contact zone, resulting in hybrids that
have intermediate phenotypes and genotypes; and (3) partial
reproductive isolation is achieved through a narrow hybrid
zone maintained by selection against hybrids; if so, D.
psarodes is best treated as a separate species.
Field Sampling
From April to December 2013, we captured flamebacks
using mist nets and dip nets along a 430 km transect
extending from the range of D. psarodes (Southern
Province; 06.048N, 79.558E) into the range of D. b.
jaffnense (Northern Province; 09.468N, 80.078E). Sites
were surveyed in intervals of ~50 km in allopatry and
~10 km in sympatry (i.e. across the transition zone
between the 2 forms) using optical and acoustic cues, and
playback of drumming calls. When a bird was located, call
playbacks and a decoy (a life-size replica made out of
plastic resembling a Dinopium male) were used to entice
the bird to fly to the mist net (Seneviratne et al. 2012).
From captured birds we measured morphology and
plumage, obtained a blood sample (~50 lL), a set of
photographs (to be maintained as a reference collection
for later phenotypic analysis), and determined the sex
(males have red crowns, females have white spots on the
forward part of their crowns). We geo-referenced the
capture site of each bird.
The Auk: Ornithological Advances 133:497–511, Q2016 American Ornithologists’ Union
498 Phenotypic and genotypic analysis of Dinopium psarodes S. P. Fernando, D. E. Irwin, and S. S. Seneviratne
Museum Specimen Sampling
We examined 55 skins from different collections in the
National Museum of Sri Lanka (Appendix Table 6). Similar
to our treatment of live birds in the field, we measured
phenotypic characters (see below) and obtained a toe pad
for tissue sample (5 mg) and photographs from each skin.
A bench-mounted white light source was used to
illuminate specimens for photographs.
Morphology and Plumage Measurements
We measured 8 variables: culmen length, bill height and
bill width to calculate the bill breadth (sum of bill height
and width divided by 2); head length and head width to
calculate the size of the head (sum of head length and
width divided by 2); and flattened wing length, tail length,
length of hind reduced digit, first claw length, and tarsus
length (Baldwin et al. 1931, Seneviratne et al. 2012). A
single observer (S.F.) measured all the characters in both
field and museum specimens.
We evaluated 21 color-based characters: color of the
forehead, crown, mustache (malar) band, supercilium, face
region (between mustache and supercilium bands), chin,
breast, scapulars, back (mantle), rump, upper tail coverts,
tail, belly, primaries, secondaries, middle coverts, and
upper and lower wing coverts. Color analyses were based
on Munsell (1976) color charts. We measured 3 plumage
metric characters using a dial caliper (0.01 mm): mustache
width (measured ventral to the eye), width of the face
region, and width of the supercilium. A single observer
(S.F.) evaluated the intensity of carotenoid-based color
expression (black 0%, golden yellow 17%, yellow 33%,
orange 67%, red orange 83%, red 100%) in different
plumage patches. We also compared RGB (Red, Green,
Blue) and CMYK (Cyan, Magenta, Yellow, Black) values for
these above color patches and recorded percentages of
each color value (Fernando and Seneviratne 2015).
Amplification and Sequencing of Genes
We stored blood and toe pad samples in Queen’s lysis buffer
(Seutin et al. 1991) and extracted DNA using standard
phenol-chloroform DNA extraction. We followed the same
procedures that we used to amplify and sequence DNA
(Seneviratne et al. 2012) with several modifications. At least
4 samples per taxon were sequenced for all flameback taxa
presented in this study. Other sequences were obtained
from GenBank to construct a consensus sequence for each
species and identify species-diagnostic variation (Appendix
Table 7 and Appendix Table 8). To estimate genetic
relationships, we amplified and sequenced the cytochrome
b(Cytb) gene (see below) of the mitochondrial genome.
Mitochondrial Genome: Cytochrome b(Cytb; 481bp)
We amplified a 481 base pair (bp) region of Cytb, using the
primer combination Cyto_b_F and Cyto_b_R (Benz et al.
2006; Appendix Table 7). The PCR reaction mix was as
follows: 1X PCR buffer (Life Technologies, Carlsbad,
California, USA), 1.5 mM MgCl (Life Technologies), 0.2
mM dNTP mix (Promega, Madison, Wisconsin, USA), 0.5
mM Cyto_b_F and Cyto_b_R primers, 0.04 units/lLTaq
DNA polymerase (Life Technologies), and 2.5 ng/lL
template DNA, in a total volume of 10 lL. Thermal cycler
conditions for Cytb included an initial 3 min at 948C,
followed by 35 cycles of 20 s at 948C, 15 s at 538C, 60 s at
728C, followed by a 7 min final extension at 728C.
Sequence Alignment: Genotyping and Phylogenetic
Sequences for other species of Dinopium and the outgroup
Picus from a neighboring biogeographic region were
downloaded from NCBI GenBank and all the sequences
were multiple aligned with clustalW (MBL-EBI, Wellcome
Trust Genome Campus, Cambridgeshire, UK) in Geneious
6.1.6 (Biomatters Limited, Auckland, New Zealand). Max-
imum-likelihood (ML) trees were generated using RaxML
(Exelixis Lab, Scientific Computing Group, Heidelberg
Institute for Theoretical Studies, Heidelberg, Germany),
using rapid bootstrap, for 1,000 replicates with the GTRþG
model using different outgroup species (Appendix Table 7).
Multiple sequences of Cytb of allopatric D. psarodes and
D. b. jaffnense were then aligned with the Zebra Finch
(Taeniopygia guttata) mitochondrial genome (Genebank
accession number NC_007897; our sequences aligning
within the range from 14246 to 14727 bp of the genome)
to identify nucleotide sites with differences between the 2
forms, such that those informative markers could be used
to genotype intermediate forms and estimate their
ancestry. A total of 16 haplotypes was identified, which
include 15 polymorphic sites. Analyses were done using
DnaSP program ( A taxonom-
ically informative G/A polymorphism was observed at
14391 bp, with allopatric D. b. jaffnense having nucleotide
G and allopatric D. psarodes having nucleotide A.
Cline Construction
We collapsed latitude and longitude data of sampled birds
to a single dimension by measuring the shortest geograph-
ic distance from the capture location of each bird to the
southeastern coast of mainland India (as shown in Figure
1A; we call this distance the ‘‘Geographic Distance’’). We
used the program CFit-7 (Gay et al. 2008, Lenormand and
Gay 2008) to estimate parameters for the best-fitting cline
for the Cytb marker (as in Seneviratne et al. 2012). The
cline was estimated as a simple sigmoidal curve across the
contact zone. We treated the genetic trait as a simple two-
allele system with each individual carrying a single Cytb
We also used CFit-7 (with the unimodal model) to fit
clines for PC1 scores of morphological and plumage
The Auk: Ornithological Advances 133:497–511, Q2016 American Ornithologists’ Union
S. P. Fernando, D. E. Irwin, and S. S. Seneviratne Phenotypic and genotypic analysis of Dinopium psarodes 499
characters. However, to better visualize the clinal variation of
those phenotypic traits, we also fit cubic splines in program
R (R Development Core Team 2010). We used CFit-7 to test
whether the plumage, morphology, and genetic clines are
coincident (i.e. have the same location) and concordant (i.e.
have the same width); differences in location and width can
be due to different patterns of selection, dispersal, inheri-
tance, and associations between genes on these traits (Barton
and Hewitt 1985). We compared each of the 4 combinations
(unconstrained, centers constrained, slopes constrained, and
both center and slope constrained) of the 3 phenotypic and
genetic clines. The likelihood-ratio test and Akaike infor-
mation criterion (Akaike 1974) were used to determine the
best model with varying sets of constraints on cline centers
and slopes.
Testing Whether Selection Maintains the Hybrid Zone
To test whether selection maintains the zone width, we
compared the width obtained through cline analysis of
field samples across the hybrid zone with the expected
width of a neutrally expanding cline: w¼1.68rffiffiffiffi
1977, Brelsford and Irwin 2009), where wis the width of
the neutral cline, ris the root mean square dispersal per
generation (distance between parent and offspring breed-
ing sites), and Tis the time in generations since secondary
contact (Endler 1977). A narrow hybrid zone compared to
neutral expectations would suggest that some form of
selection maintains the zone (Barton and Hewitt 1989,
Jiggins and Mallet 2000).
No estimates of dispersal distance are available for
Dinopium or other Asian woodpeckers. Therefore we used
estimates of generation time and dispersal of a New World
woodpecker, the Northern Flicker (Colaptes auratus). Root
mean square dispersal (r) was estimated as 100 km per
generation (estimates for C. auratus; Moore and Buchanan
1985). Generation time was estimated as 1.9 years,
calculated as in Mila
´et al. (2007) based on the annual
survival rate (0.41–0.53; Wiebe 2006), geometric popula-
tion growth (assuming the population is in demographic
equilibrium k¼1; Mila
´et al. 2007), and the age of first
breeding (1 year; Walters et al. 2002a, 2002b). We
alternatively used a highly conservative estimate of root
mean square dispersal (r) based on North American
songbirds (10 km per generation; Paradis et al. 1998).
We considered 2 levels of time since secondary contact
of the parental taxa: 10,000 years and 160 years. The
climate and other biogeographic characteristics of Sri
Lanka remained more or less stable since the Miocene
period (Bossuyet et al. 2004). Therefore we assume the
secondary contact of D. psarodes and D. b. jaffnense took
FIGURE 1. Allopatric distribution of D. b. jaffnense and D. psarodes and the existence of a hybrid zone between the 2 forms as seen
from the capture locations of Dinopium flamebacks, frequency distribution of mitochondrial haplotype (Cytb), and the frequency
distribution of plumage color in Sri Lanka. (A) Capture locations of field and museum specimens. The lines indicate the distance from
the southeastern coast (Dhanushkodi) of mainland India. Squares denote field capture locations and triangles denote the locations
of museum specimens: green ¼D. b. jaffnense, orange ¼Dinopium intermediate, red ¼D. psarodes.(B) Frequency distribution of
mitochondrial haplotype (Cytb): green ¼northern haplotype, red ¼southern haplotype. (C) Frequency distribution of plumage color:
green ¼D. b. jaffnense, yellow/ red and yellow ¼Dinopium intermediate in the hybrid zone, red ¼D. psarodes. The 2 lines indicate the
northern and southern borders of the hybrid zone. The province boundaries are also shown.
The Auk: Ornithological Advances 133:497–511, Q2016 American Ornithologists’ Union
500 Phenotypic and genotypic analysis of Dinopium psarodes S. P. Fernando, D. E. Irwin, and S. S. Seneviratne
place during the last complete exposure of the Adams
Bridge (the land bridge that connects Sri Lanka to the
mainland India) due to the drop of sea level ~10,000 years
ago (Ripley 1949, Hopkins 1967). However the secondary
contact may be more recent (de Silva et al. 2014). We used
160 years as our most conservative estimate of secondary
contact based on the time where the species was first
described to science in 1853 by the British ornithologist E.
L. Layard (note that intermediate phenotypes of Dinopium
were common in northern Sri Lanka even in 1868–1877;
Legge 1880).
Analysis of the Phenotype
To summarize patterns of variation between plumage and
size, we carried out separate principal components
analyses (PCA) using correlation matrices, first for the 8
morphological characters and second for the 21 plumage
characters. The principal axis method was used to extract
the components without rotation. The majority of
variation was captured by the first component (PC1) in
both analyses (morphometric and plumage) and only the
first 2 components displayed eigenvalues greater than 1.
Therefore we used the first 2 principal components for the
rest of the analysis. To examine the relationship between
the parental genotypes with parental phenotypes, we used
one-way ANOVA with Tukey’s family error post hoc test
(Sokal and Rohlf 1995). Since the residuals were not
normally distributed we performed a rank-based normal-
ization with Tukey’s formula. Shapiro–Wilk’s test was
executed to confirm normalization (P.0.05; Sokal and
Rohlf 1995). Significance level was set at P,0.05. All
statistical analyses were performed with SPSS 20.0 (IBM
Corporation, Armonk, New York, USA).
Evaluation of del Hoyo et al. (2014) Criteria of
Splitting D. benghalense
We compared our dataset with the data used by del
Hoyo et al. (2014) to split D. psarodes as a full species
following the criteria proposed by Tobias et al. (2010;
Table 1). Tobias et al. (2010) used the strength of
differentiation in various characters according to effect
sizes computed from the means and standard deviations.
Effect sizes are most commonly presented as the Cohen’s
dstatistic [d¼X
pooled ,
where X¼mean of
species 1 and 2, S¼standard deviation, and S
pwhere n¼
number of individuals sampled in species 1 and 2], which
expresses the difference in means in terms of the amount of
within-group variation (Tobias et al. 2010). On the basis of
the distribution of effect sizes produced by empirical tests of
divergence in undisputed species, they have scored
character differences with an effect size of 0.2–2 as minor,
2–5 as medium, 5–10 as major, and .10 as exceptional.
We sampled 70 individuals across the island along a 430 km
transect; based on plumage these were identified as 41 D.
psarodes,17D. b. jaffnense, and 12 intermediate forms of
varied levels of orange plumage. These birds included 32
males and 38 females (sex was determined using plumage;
see Methods). We did not observe any sexual differences in
TABLE 1. Comparison of del Hoyo et al. (2014) analysis for splitting Dinopium psarodes as a full species with present data shows a
similar conclusion. ‘‘Scores’’ ¼introduced by del Hoyo et al. (2014).
del Hoyo et al. (2014) Our study
Minor characters Scores
Minor characters
(D. psarodes vs. D. b. jaffnense) Scores
Biometrics Longer billed
Longer winged
Longer tailed
Effective size ¼2.92
2 Longer billed (34.1 mm vs. 32.5 mm)
Longer winged (138.5 mm vs. 133.6 mm)
Longer tailed (94.7 mm vs. 86.9 mm)
Effective size ¼4.21
Acoustics Screechy call (louder and higher-pitched
1 Not quantitatively analyzed (louder and
higher-pitched call)
Plumage and
bare parts
Scarlet central upper parts shading to dull
red on wings vs. golden yellow shading
to dull yellow
Lack of black on carpal
Effect size not reported
Contrasting difference in color
Red vs. golden yellow
Lack of black on carpal
Effective size ¼6.73
Ecology and
Non-overlapping differences in foraging/
breeding habitat
1 Non-overlapping differences in foraging/
breeding habitat
Narrow hybrid zone 2 Narrow hybrid zone (hybridization between
D. psarodes and D. b. jaffnense occurs
over a range ,200 km at its maximum
Total scores 10 10
The Auk: Ornithological Advances 133:497–511, Q2016 American Ornithologists’ Union
S. P. Fernando, D. E. Irwin, and S. S. Seneviratne Phenotypic and genotypic analysis of Dinopium psarodes 501
morphological traits in either species (one-way ANOVA, F
¼0.40, df ¼1 and 70, P¼0.53), other than the slight color
difference in forehead plumage. From the national collec-
tion we sampled 25 D. psarodes,8D. b. jaffnense,and22
intermediate types (Figure 2G). Since museum and field
data originated from different sampling locations (Figure
1A), we analyzed them separately.
Plumage color of the back ranges from red to yellow,
with many intermediate colors (Figure 2) as suggested by
previous authors (e.g., Fernando and Seneviratne 2015,
Freed et al. 2015). A clinal change of plumage characters
was observed along the line transect from Jaffna (northern
tip of the island: 9.468N, 80.078E) to Matara (southern tip
of the island: 6.048N, 80.388E; Figures 1C, 3C). All
individuals captured from Jaffna peninsula had yellow
backs (Figure 1A). All individuals captured from the core
of the wet zone (southern parts of the island) had crimson-
red backs (Figure 1A). The intermediate plumage colors
(orange) were found in varying proportions in the north-
central dry zone, from the southern border of Wilpathu
National Park (08.378N, 80.078E) up to Kilinochchi
(9.228N, 80.258E).
A clinal change of genetic characters (in Cytb) was
observed in the line transect across north-central Sri Lanka
(Table 2; Figures 1B, 3A). Allopatric D. b. jaffnense has a G
nucleotide and allopatric D. psarodes has an A at the
diagnostic polymorphic site in Cytb gene. In the sympatric
area a mixture of these Cytb types was found among the
intermediate phenotypes.
Our Cfit analysis positioned cline centers 83–149 km
(mean center ¼115 km) from the southeastern coast of
mainland India (Table 3). The Cytb-based genetic cline and
the center- and slope-constrained cline based on all traits
positioned the cline center at 115–117 km from the coast of
FIGURE 2. Color variation of Dinopium flamebacks in Sri Lanka: (A) crimson-red plumage (D. psarodes) (image courtesy of V.
Weeratunge), (B) reddish-orange form, (C) orange form, (D) orange-yellow form, (E) orange/reddish mantle, (F) golden-yellow
plumage (D. b. jaffnense) (image courtesy of V. Weeratunge), and (G) variation of back color in Dinopium flamebacks in the national
collection (image courtesy of the Department of National Museums, Sri Lanka).
TABLE 2. A composition of genotypes of flameback woodpeck-
ers at Cytb gene along the transect line showing a mixture of
genotypes among the intermediate phenotypes in the sympat-
ric area.
Phenotype Individuals
Cytb gene
Northern allopatric area
D. b. jaffnense 10 10
Sympatric area
D. b. jaffnense 642
D. psarodes 13 10 3
Dinopium intermediates 8 4 4
Southern allopatric area
D. psarodes 31 31
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502 Phenotypic and genotypic analysis of Dinopium psarodes S. P. Fernando, D. E. Irwin, and S. S. Seneviratne
India (Table 3; Figure 3A). The widths of these clines range
from 18 to 142 km among different traits. The constrained
clines, which Akaike Information Criterion (AIC) values
indicate should be taken as the best model, gave the center
as 117 km and width as 118 km (Table 3). Cubic splines of
both morphological and plumage traits showed clinal
variation in the same area that of Cytb: ~117 km from
the southeast coast of India (line north of Putlum to
Vavunia; Figures 1C & 3). These 3 measured traits are
generally concordant in their centers and widths (Figure 3).
When we compare the empirical clines with hypothetical
neutral clines unaffected by selection, the empirical clines
were always narrower than the neutral clines. Assuming
that the secondary contact of D. psarodes and D. b. jaffnense
took place during the last complete exposure of the Adams
Bridge due to the drop of sea level (~10,000 years ago:
Ripley 1949, Hopkins 1967), and given the dispersal rate and
generation time of C. auratus, a neutral cline would have
now reached a width of ~1,700 km. A highly conservative
(i.e. minimal) estimate of time since recent contact between
taxa (160 years, based on Layard’s [1853] original descrip-
tion of the red form and dispersal rate of songbirds) would
give a width of 213 km. Just 15 years after this first
description came the documentation of intermediate
phenotypes between D. psarodes and D. b. jaffnense (Legge
1880). Assuming 1868 as the time of secondary contact
would give a cline width of 192 km—still a much wider cline
compared to the observed clines (112 km). The narrowness
of the empirical clines suggests some form of selection
constrains the width of the cline; such selection can be
considered a form of partial reproductive isolation that
hinders the blending of the 2 forms and stabilizes them as
distinct entities (Barton and Hewitt 1985, 1989).
Dinopium flamebacks in Sri Lanka all have red crowns,
and plain black napes and upper mantles (Figure 2A–F).
However, their backs have 2 predominant color types
(Figure 2A–F), crimson-red and olive-yellow, correspond-
ing to the 2 forms. The intermediate color forms range
from golden yellow (Figure 2F) to orange (Figure 2C). The
orange color is sometimes confined to the mantle, and
sometimes extends more prominently into the wings.
Secondaries and coverts show olive-yellow, golden yellow,
orange, and crimson red (Figure 2A–F). D. psarodes in the
extreme south has crimson-red shading in the primaries
and in the otherwise black rump as well (Figure 2A).
Similarly, the amount of black and white plumes on the
facial region and upper wing coverts shows slight variation
along the north–south transect. The northern (dry-zone)
birds of all color types have broader white supercilium and
malar stripes (mustache). Birds in the south (wet-zone)
have narrower white facial stripes (hence darker faces;
Figure 2A). Upper wing coverts are dotted with 2 rows of
white spots in northern birds (Figure 2E, 2F); these spots
are less prominent in the southern birds (Figure 2A). In all
TABLE 3. Comparison of genetic, plumage, and morphometric clines based on maximum log-likelihood estimates obtained from Cfit-7. Cline centers are in kilometers from
the nearest coast of mainland India. Likelihood ratio tests and Akaike Information Criterion (AIC) indicate that a single cline (Model 4) best represents variation in all of these
traits. *Asterisks indicate similar centers or widths due to constrained models.
Allele (Cytb) Plumage Morphometric
Log-likelihood AIC
115/112 v
PCenter (km) Width (km) Center (km) Width (km) Center (km) Width (km)
1. No constraint 115 142 149 82 83 18 188.36 408.72
2. Center constrained 73 250 * 138 * 4 190.56 417.84 1 and 2 4.4 0.89
3. Slope constrained 116 114 117 * 63 * 191.63 411.26 1 and 3 6.54 0.96
4. Center and slope constrained 117 118 * * * * 191.85 407.7 1 and 4 6.98 0.86
2 and 4 2.58 0.73
3 and 4 0.44 0.20
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S. P. Fernando, D. E. Irwin, and S. S. Seneviratne Phenotypic and genotypic analysis of Dinopium psarodes 503
forms along the transect the throat is black, bill blackish
grey, iris chestnut, breast and belly have dark chevrons and
streaks, and legs are gray.
Bill length (i.e. total culmen), wing length, and tail
length are smaller in D. b. jaffnense than in D. psarodes and
intermediates (Table 4). In the morphology-based PCA,
PC1 explained 64.6% of the variation and described size
differences between the species (Table 5, Figure 4A). In the
morphological PCA, many traits contributed heavily to
PC1 (Table 5) and there was a clear separation of D.
psarodes and D. b. jaffnense in PC1 (ANOVA; P,0.001).
In the plumage PCA, PC1 captured 66.2% of the variation,
correlating well with all characters that tend to differ
between D. psarodes and D. b. jaffnense (ANOVA; P,
0.001; Table 5 and Figure 4B).
Both Sri Lankan and Indian yellow forms of D.
benghalense are clustered together, and form a sister group
to Sri Lankan red form (D. psarodes) at Cytb (Figure 5).
Our analysis of biometrics following Tobias et al. (2010)
and del Hoyo et al. (2014) is consistent with the latter
analysis (which resulted in splitting the D. psarodes into a
full species) but with a greater effect size (4.21 rather than
2.92). Likewise, the quantitative analysis of plumage and
bare parts (effect size 6.73), ecology, behavior, and
geographical relationship too are in accordance with del
Hoyo et al. (2014) (Table 1).
We examined phenotypic and genotypic relationships
within 2 distinct forms of Dinopium flamebacks in Sri
Lanka to test the validity of the newly elevated species D.
psarodes, the Red-backed Woodpecker or the Lesser Sri
Lanka Flameback (del Hoyo et al. 2014), a distinct form
endemic to the island of Sri Lanka. We documented clear
phenotypic and genetic evidence for a hybrid zone, and
find that this hybrid zone is narrower (112 km in width)
than that expected for a neutrally expanding zone. The
narrow hybrid zone suggests some form of selection acts
against hybrids; such selection is considered a form of
partial reproductive isolation (Barton and Hewitt 1985,
1989, AOU 1998, Brelsford and Irwin 2009).
Is D. psarodes a good species under the biological
species concept? We argue that despite extensive hybrid-
ization in sympatry, there are several key factors suggesting
that D. psarodes is best considered a distinct species. It is
phenotypically (Figures 2 and 4) and genetically (Figures
3A and 5) a distinct entity. Except for hybrids in this
narrow contact zone (Table 3), it does not show
intermediate phenotypes in the rest of its range, and
breeding areas of D. psarodes and D. b. jaffnense remain
largely separated from each other. When our data is
evaluated under the species-delimiting criteria used in
Tobias et al. (2010), we find strong support for the species
status of D. psarodes.
Phylogenetic affinities based on Cytb support D.
psarodes’s separation from D. benghalense cluster (Figure
5). A much broader phylogenetic analysis on this group
using very large amount of genomic sequence (152,311bp)
generated by Restriction Site Associated DNA (RAD)
sequencing also revealed a similar pattern (de Silva et al.
2014), where D. b. jaffnense cluster with the Indian forms
TABLE 4. Morphological and plumage traits measured in Dinopium flamebacks showing that beak, wing, and tail length of D.
psarodes are longer and supercilium and mustache width are narrower in D. psarodes than in D. b. jaffnense (mean 6SE, with data
range in parentheses).
Field sample (n¼70)
D. psarodes (n¼41) D. b. jaffnense (n¼17) Intermediate (n¼12)
Morphometric traits (mm)
Head length 29.66 61.93 (21.90–32.30) 30.52 60.97 (29.30–32.20) 30.42 61.67 (27.30–32.00)
Head width 21.82 60.76 (19.51–23.60) 21.26 60.55 (20.21–22.20) 21.28 60.90 (19.00–22.30)
Beak length 34.15 61.63* (30.61–36.70) 33.50 62.07 (30.60–37.22) 32.61 62.50 (29.80–36.90)
Bill height 8.96 61.00 (8.22–10.50) 8.91 60.54 (7.90–10.30) 8.76 60.85 (7.60–9.80)
Bill width 9.11 60.81 (7.42–11.00) 8.36 60.81 (6.72–9.55) 9.16 60.70 (7.90–10.10)
Flat-wing length 138.59 66.22* (130.52–142.20) 133.60 62.82 (129.00–138.00) 131.64 62.34 (129.00–135.00)
Tarsus length 27.50 61.99 (22.45–30.94) 24.14 61.01 (23.00–26.90) 25.90 62.03 (22.80–28.70)
Tail length 94.70 61.48* (76.00–139.00) 82.92 63.10 (79.00–91.00) 86.80 60.83 (74.00–98.00)
1st claw length 8.94 60.25 (8.30–9.65) 8.96 60.33 (8.40–9.50) 8.97 60.54 (8.10–9.80)
Length of the
reduced hind digit 4.40 60.98 (2.50–6.60) 4.16 60.66 (2.80–5.42) 4.68 60.94 (3.30–6.30)
Plumage traits**
Supercilium width 2.69 60.69* (1.30–4.32) 3.37 60.98 (1.50–6.12) 3.00 60.89 (1.80–4.20)
Face width 7.33 61.11 (4.55–9.20) 7.00 60.50 (6.32–8.00) 6.99 61.18 (5.20–8.54)
Mustache width 3.17 61.18* (1.40–8.92) 3.68 60.80 (2.00–5.00) 3.24 60.66 (2.40–4.40)
*P,0.05 compared to D. b. jaffnense (ANOVA with Tukey’s family error post hoc test).
** Length or width measured in millimeters (mm).
The Auk: Ornithological Advances 133:497–511, Q2016 American Ornithologists’ Union
504 Phenotypic and genotypic analysis of Dinopium psarodes S. P. Fernando, D. E. Irwin, and S. S. Seneviratne
and the D. psarodes separates out as the sister group with
posterior probability of close to 1 (de Silva et al. 2014).
Our multivariate analysis further showed that D.
psarodes is a distinct phenotypic entity diagnosed by
crimson back, black rump and upper tail coverts, and
slightly longer tail and tarsus. Intermediate phenotypes
were clustered between the 2 parental phenotypes (Figures
3 and 4). The intermediates were found in the contact area
between the parental groups, in a narrow band north of
Puttalum to Killinochi in the north-central and north-
western parts of Sri Lanka (Figure 1). The center of the
hybrid zone lies roughly in the middle of this band (~112
km from the mainland; Figure 3). We found crimson-red,
red, orange-red, orange, golden yellow, and olive-yellow
phenotypes of Dinopium in this area (Figure 2). Legge
(1880) and several others over the past century have made
similar observations (see Introduction). We encountered
heterospecific pairs at the center of the hybrid zone as well.
For example, in Wilpattu National Park in northwestern
Sri Lanka (08.378N, 80.088E), we observed a nest with
nestlings where the parent male was a D. psarodes and the
female was a D. b. jaffnense. A previous observer also has
noted similar heterospecific pairs in this same region
(Freed et al. 2015).
Despite the plumage differences, these woodpeckers are
vocally very similar (Rasmussen and Anderton 2012). We
observed only subtle differences in the frequency in their
calls (S. Seneviratne personal observation). In fact both
species and their hybrids respond to each other’s playback
Sri Lanka has 2 main climatic zones. The southern one-
third of the island is the wet zone with over 2,500 mm
annual rainfall. The rest of the island, including the
TABLE 5. Variance explained and factor loading of the first 2
principal components (PC) produced in principal components
analyses (PCAs) of phenotypic traits: A) morphological traits and
B) plumage traits.In the morphological PCA, PC1 explained 64.6%
of the variation and described size differences between the
species, with each standardized morphological variable being
roughly equally correlated with PC1 (Figure 4). PC1 scores of
morphological traits separate the 2 species. The PC1 of plumage
captured 66.2% of the variation. PC2 of both morphological and
plumage traits captured minor amounts of variation.
Field samples (n¼70)
(A) Morphometric traits
Eigenvalue 2.67 0.80
Variance explained 64.6% 10.5%
Factor loadings
Tail length 0.53 0.30
Tarsus 0.34 0.49
Head width 0.54 0.23
1st claw length 0.43 0.30
Exposed culmen 0.64 0.11
Hind reduced digit 0.04 0.55
Flat-wing length 0.44 0.14
Head size 0.38 0.64
Head length 0.15 0.63
Bill height (mm) 0.34 0.050
Bill breadth 0.29 0.07
Bill width (mm) 0.11 0.04
(B) Plumage traits
Eigenvalue 3.82 1.17
Variance explained 66.2% 20.7%
Factor loadings
Back color 0.67 0.19
Rump color 0.86 0.15
Secondary coverts color 0.67 0.16
Supercilium width 0.43 0.66
Face width 0.23 0.59
Mustache width 0.26 0.74
TABLE 4. Extended.
Museum skins (n¼55)
D. psarodes (n¼25) D. b. jaffnense (n¼8) Intermediate (n¼22)
29.87 62.69 (25.60–35.90) 28.8 63.78 (25.80–36.20) 29.85 62.38 (24.80–36.20)
22.63 61.14 (20.00–25.00) 21.51 62.04 (20.00–25.40) 22.04 61.98 (18.20–25.40)
32.05 63.25 (21.80–37.80) 30.76 61.39 (29.10–33.10) 30.83 63.17 (29.10–31.30)
9.07 60.61 (8.00–10.80) 8.65 60.58 (8.10–9.70) 8.56 60.69 (8.10–9.70)
8.07 60.64 (6.90–9.40) 7.40 60.48 (6.82–8.11) 7.61 60.70 (6.80–8.10)
129.33 62.56 (108.00–142.00) 130.83 65.27 (125.00–138.00) 127.71 67.87 (125.00–138.00)
24.15 61.77 (21.50–28.20) 22.48 61.01 (21.50–24.00) 22.10 61.86 (21.50–24.00)
97.25 65.14 (89.00–111.00) 97.17 63.37 (92.00–102.00) 97.72 61.95 (92.00–102.00)
9.72 61.28 (7.00–12.00) 9.30 60.98 (7.60–10.40) 9.14 60.84 (7.70–10.40)
2.47 60.58 (1.40–3.90) 3.00 60.62 (2.10–3.80) 2.90 60.55 (1.80–3.80)
6.54 61.10 (5.00–9.20) 6.10 61.30 (4.50–8.30) 6.49 61.02 (4.80–8.30)
3.05 60.59 (2.00–4.90) 3.71 60.51 (2.80–4.10) 3.55 60.84 (2.10–4.10)
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S. P. Fernando, D. E. Irwin, and S. S. Seneviratne Phenotypic and genotypic analysis of Dinopium psarodes 505
northern parts near mainland India, is the dry-zone with
seasonal rainfall averaging ~1,500 mm (Ashton et al.
1997). The Sri Lankan endemic D. psarodes is bigger, and
has longer bill breadth and length, than D. b. jaffnense.A
possible reason is that the trees in the wet zone forests are
much bigger, such that the bigger bill of D. psarodes can
better excavate the thick bark. The supercilium and
mustache width of D. psarodes are narrower than that of
D. b. jaffnense (Table 4). The darker plumage coloration
and the longer beak are general patterns shown by the
birds in the wet zone of Sri Lanka compared to their dry-
zone and Indian counterparts (Ripley 1946, 1949, Ripley
and Bheeler 1990). This fits the general pattern of higher
humidity being associated with darker and bigger individ-
uals (Prum et al. 2012, Fernando and Seneviratne 2015).
Mainland India and northern Sri Lanka are similar in
humidity, and a similar plumage can likewise be found in
both the mainland and the island (Fernando and
Seneviratne 2015). D. psarodes is found in the dry zone
of Sri Lanka as well, but there they are found closer to
water bodies such as lakes and rivers, which are abundant
in the dry zone. This may indicate that D. psarodes prefers
humid habitats compared to its dry-zone counterpart.
Here we have provided the first comprehensive analysis
incorporating both phenotypic and genetic variation across
a hybrid zone for an Old World woodpecker group. We
FIGURE 3. Clinal variation of allele frequency, morphology, and plumage of Dinopium along an axis representing distance from the
southeastern coast of mainland India showing the allopatric distribution of D. b. jaffnense and D. psarodes and the presence of the
hybrid zone. Zero kilometers represents the nearest southeastern coastal line of India (Figure 1A). Points represent mitochondrial
haplotype frequency (red indicates southern Cytb haplotype and green indicates northern haplotype) in groups of local individuals
(A) or PC1 scores (morphological and plumage characters) of individuals (BC: red dots indicate red forms, orange triangles indicate
intermediate forms, and green dots indicate yellow forms). The lines represent the best-fitting clines generated by CFit-7. Dark gray
area indicates the width of the genetic cline. (A) Cytb gene, (B) Morphology, (C) Plumage.
The Auk: Ornithological Advances 133:497–511, Q2016 American Ornithologists’ Union
506 Phenotypic and genotypic analysis of Dinopium psarodes S. P. Fernando, D. E. Irwin, and S. S. Seneviratne
conclude that D. psarodes of Sri Lanka is both genetically
and phenotypically a distinct entity that warrants full
species status. Our study provides an example in which the
phenotype-based criteria proposed by Tobias et al. (2010)
for avian taxonomy are consistent with conclusions arrived
at through genetic and cline-based analyses. Hence the
conclusion of del Hoyo et al. (2014) to elevate D. psarodes
to a distinct species. Detailed studies on the amount of
introgression in the context of hybridization, the stability
of the hybrid zone and the fate of its hybrids, and the
ecology of the new species (D. psarodes) would shed more
light into this charismatic group of poorly known Asian
Prof. Gaya Ranawaka of the Open University of Sri Lanka,
Prof. Sarath Kotagama and Prof. Preethi Udagama of
University of Colombo provided assistance in various stages.
We thank Kelum Manupriya and numerous other field
assistants for their assistance in the field. We thank Janaka
Perera, Indrika Kaggodaarachchi, Nelum Wickramasighe, and
Manori Goonathilaka for their assistance both in the field and
at the National Museum. Three anonymous reviewers and
Kristen Ruegg gave valuable comments to early versions of the
manuscript. The Department of National Museums provided
the needed permission to sample the national collection. The
Department of Wildlife Conservation (permit nos. WL/3/2/
FIGURE 4. Variation of morphological (A) and plumage (B) characters in adult D. b. jaffnense and D. psarodes showing clear
separation of D. psarodes only in plumage. Red ¼D. psarodes, orange ¼intermediate, green ¼D. b. jaffnense.
FIGURE 5. Molecular phylogenetic analysis by maximum-likelihood method for Cytb gene.
The Auk: Ornithological Advances 133:497–511, Q2016 American Ornithologists’ Union
S. P. Fernando, D. E. Irwin, and S. S. Seneviratne Phenotypic and genotypic analysis of Dinopium psarodes 507
19/13 and WL/3/2/41/14) and Forest Department (permit no.
RE/RES/NFSRC/13) provided the permits to carry out the
study in the field.
Funding statement: A Collaborative Research Grant of the
University of Colombo to S.S.S. (AP/3/2012/CG/30) funded
this study. Our funder had no influence on the content of the
submitted or published manuscript and our funder did not
require approval of the final manuscript to be published.
Ethics statement: This study has been approved by the
Research Committees of the Department of Wildlife Conser-
vation of Sri Lanka (permit nos. WL/3/2/19/13 and WL/3/2/
41/14), the Forest Department of Sri Lanka (permit no. RE/
RES/NFSRC/13), and the Higher Degrees Committee of the
Faculty of Science, University of Colombo.
Author contributions: S.P.F. designed and conducted field-
work and laboratory experiments, performed the analysis, and
wrote the paper. D.E.I. assisted with formulating the research
question and writing the paper. S.S.S. conceived the idea,
formulated the research question, designed field and labora-
tory experiments, provided funding, and wrote the paper.
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S. P. Fernando, D. E. Irwin, and S. S. Seneviratne Phenotypic and genotypic analysis of Dinopium psarodes 509
APPENDIX TABLE 6. Summary of the sampled specimens at the
National Collection, National Museum, Colombo, Sri Lanka.
number Collected date Species Sex
127-2 March 23, 1969 D. psarodes Male
127-V March 3, 1934 D. psarodes Female
127-I August 14, 1913 D. psarodes Male
127-Q November 7, 1923 D. psarodes Female
127-B August 21, 1905 D. psarodes Female
127 August 22, 1905 D. psarodes Male
127-R November 27, 1933 D. psarodes Male
127-T March 3, 1934 D. psarodes Male
127-Z May 16, 1961 D. psarodes Female
127-P May 22, 1932 D. psarodes Male
129-Z January 31, 1940 D. psarodes Male
129-X January 17, 1940 D. psarodes Male
129-T June 30, 1951 D. psarodes Female
127-E February 9, 1913 D. psarodes Male
127-X July 31, 1958 D. psarodes Male
127-1 September 13, 1961 D. psarodes Female
127-Y March 31, 1961 D. psarodes Female
127-A February 15, 1906 D. psarodes female
127-L November 8, 1923 D. psarodes female
127-K August 12, 1913 D. psarodes male
127-M December 2, 1920 D. psarodes female
127-N November 20, 1924 D. psarodes male
127-O November 7, 1923 D. psarodes female
127-D August 6, 1913 D. psarodes-HYB female
127-H August 23, 1905 D. psarodes male
126-Z May 30, 1947 D. b. jaffnense-HYB male
126-1 May 8, 1947 D. b. jaffnense male
126-i March 14, 1933 D. b. jaffnense-HYB female
126-Y February 17, 1959 D. b. jaffnense-HYB male
126-F September 10, 1919 D. b. jaffnense-HYB female
126-P July 1, 1951 D. b. jaffnense-HYB male
126-T November 17, 1953 D. b. jaffnense-HYB female
126-D August 13, 1913 D. b. jaffnense-HYB male
126-W May 28, 1958 D. b. jaffnense-HYB male
126-O June 29, 1951 D. b. jaffnense-HYB female
126-Q June 30, 1951 D. b. jaffnense-HYB male
126 February 15, 1954 D. b. jaffnense-HYB female
126-X February 15, 1952 D. b. jaffnense-HYB female
126-K March 21, 1933 D. b. jaffnense-HYB female
126-M July 23, 1945 D. b. jaffnense-HYB male
126-N July 1, 1945 D. b. jaffnense-HYB female
126-E January 23, 1911 D. b. jaffnense-HYB female
126 UNKNOWN D. b. jaffnense female
126-A April 15, 1904 D. b. jaffnense male
126-B April 15, 1904 D. b. jaffnense-HYB male
126-H March 14, 1933 D. b. jaffnense-HYB male
126-U February 9, 1956 D. b. jaffnense female
126-F September 10, 1919 D. b. jaffnense-HYB male
126-L July 22, 1945 D. b. jaffnense male
126-V February 14, 1956 D. b. jaffnense female
APPENDIX TABLE 7. List of primers used in the genetic analysis.
Gene Primer Sequence (50-30) Reference
Cytochrome b DINO_Cyto_b_F CGATTCTTCGCTTTACACTTCCTCC Benz et al. 2006
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510 Phenotypic and genotypic analysis of Dinopium psarodes S. P. Fernando, D. E. Irwin, and S. S. Seneviratne
APPENDIX TABLE 8. Summary of the samples included in the molecular analysis. Voucher number indicates the catalog numbers of
Avian Evolution Node or NCBI Genbank.
of origin
Accession number
Cytb LDH
In group
Dinopium shorii Myanmar B3291 DQ479273.1 NS
D. javanense India NRM20026532 KF765961.1 NS
D. benghalense India KC439266.1 KJ455248.1
D. psarodes Sri Lanka MD18SS03 This study This study
D. b. jaffnense Sri Lanka MG28SF01 This study This study
D. psarodes/
D. b. jaffnense
Sri Lanka MF11SS01 NS NS
Out group
Piculus chrysochloros – – NS NS
Picus viridis EU556833.1 NS
Picus flavinucha India NRM:20056713 NS KJ455282
NS ¼No sequence obtained
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... C. odorata is one of world's worst invasive alien species (World Conservation Union, 2001), and it has been recorded as a problematic weed in several national parks in Sri Lanka (Ranwala & Thushari, 2012). In UWNP, the extensive spread of C. odorata and other invasive plants has caused a loss in the extent of grassland (DWC, 2008;Fernando et al., 2016), which would be detrimental to elephants and other herbivores such as sambhur, spotted deer in the PA. ...
... The two exceptions were at Eluwankulama on 24/3/18 and at Mahawilachiya Wewa on 15/5/18. In line with Fernando et al. (2016), and following Del Hoyo (2020), we treat these two forms as separate species. The study area lies completely within the zone of hybridisation between the two forms (Fernando & Seneviratne 2015;Freed et al. 2015;Fernando et al. 2016). ...
... In line with Fernando et al. (2016), and following Del Hoyo (2020), we treat these two forms as separate species. The study area lies completely within the zone of hybridisation between the two forms (Fernando & Seneviratne 2015;Freed et al. 2015;Fernando et al. 2016). On 17 occasions the back was seen well enough to categorise the bird into psarodes type, hybrids, and benghalense type, in the ratio of 10:4:3, respectively. ...
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WILDLANKA is a peer-reviewed international journal which issues four volumes per year. Papers are reviewed by a panel of experts comprised of nationally and internationally renowned scientists. It provides an opportunity to wildlife researchers, scientists, academics, postdoctoral fellows, undergraduate students and other experts to publish their articles online as well as in print. WILDLANKA publishes works from a wide range of fields including Wildlife Conservation, Sustainable Development, Ecology, Biodiversity, Ecotourism, Biotechnology, Economics, Geoinformatics, Social Science, Engineering and Marine etc.
... Beyond its application in the context of the HBW/ BirdLife checklist or in publications by the authors of the work (Tobias et al. 2010), the 7-point rule has been utilized by a varied but limited set of additional authors, often to confirm taxonomic proposals supported through independent avenues of inquiry (Rheindt et al. 2011, Rasmussen et al. 2012, Fernando et al. 2016, Fischer et al. 2018). The 7-point rule has not been embraced as a routine taxonomic arbiter by any of the other major global checklists, any regional taxonomic authority, or any newly published regional field guide, except most of those books produced by the same publishing house as HBW and directly based on HBW's drawings and taxonomy. ...
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Prinias (Cisticolidae: Prinia) are resident warblers of open areas across Africa and Asia and include many polytypic species whose species limits have not been seriously reevaluated recently. Based on an integrative taxonomic analysis of morphology, song, and mitochondrial DNA (mtDNA), we suggest that 2 species should be recognized in the Graceful Prinia (Prinia gracilis) complex. In addition, our morphological analyses show the existence of a well-marked undescribed form in southeastern Somalia, which we name herein as a new subspecies. Prinia gracilis is a small, drab, long-tailed species with streaking above and plain pale underparts that has been suggested to fall into 2 groups: the southwestern nominate group (from Egypt to Oman) and the northeastern lepida group (from Turkey through India). However, the characters presented to justify this grouping are variable and show a mosaic pattern, and whether genetic and vocal differences exist is unknown. We found consistent between-group song differences, with the nominate group giving consistently longer inter-phrase intervals, whereas the members of the lepida group sing an essentially continuous reel. An mtDNA tree suggests a deep split between the nominate and lepida groups, with a coalescence time between these clades of ~ 2.2 million years ago. Vocal and mtDNA analyses provided evidence that the northeastern Arabian Peninsula taxon carpenteri belongs to the lepida group. We found that, of all the morphological characters proposed, only proportions and tail barring and spotting relatively consistently distinguish the 2 groups. However, these characters strongly suggest that the eastern Arabian Peninsula is populated by taxa of both the gracilis and lepida groups, in different areas, but we lack genetic and bioacoustic data to corroborate this. Although further study is needed in potential contact zones, we suggest that 2 species should be recognized in the P. gracilis complex, and we propose the retention of the English name Graceful Prinia for P. gracilis sensu stricto, while we suggest that P. lepida be known as Delicate Prinia.
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Examination of the Dendrelaphis bifrenalis populations on Sri Lanka showed that there are two populations that are morphologically different from each other. One population is distributed only in the wet zone forests (hereafter treated as wet zone population), while the other population occurs widely in the dry zone and intermediate zones (hereafter dry zone population). The type series of D. bifrenalis consist of 3 specimens from which the specimen representing the dry zone population was chosen as lectotype, and the wet zone population is described here as a new species. It clearly differs from D. bifrenalis by having a shorter snout, orbit diameter 103-114% of eye-nostril length (vs 77-95%), and larger eye, orbit diameter 21-23% of head length (vs 17-20%). Furthermore it differs by having a temporal stripe stopping just beyond the neck (vs continues behind neck), the absence of black transverse dorsolateral bars on the anterior 1/4 th of body (vs prominent), a narrow and pointed snout (vs broad and flat), a divided nasal (vs single), and a ventrolateral stripe continuing up to the tail (vs stopping at the level of the anal plate). This morphological differentiation is supported by the divergence in the mitochondrial NADH dehydrogenase subunit 4 (ND4) region separating clearly with the divergence of 1.70±0.35%. Also, here we resurrect D. effrenis (Werner, 1909) as a valid species, and D. sinharajensis as a junior synonym of it. The holotype of D. sinharajensis was chosen as the neotype of D. effrenis to stabilize nomenclature, and to make it an objective synonym. The third and fourth known specimens of this rare species are reported. A key of the species of the genus Dendrelaphis in Sri Lanka is provided.
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Waturana is the local (SInhala) term used to describe freshwater swamp-forests which may have been a quite extensive in the past, but reduced to vestiges today due to conversion of many of these swamp-forests in to other land use types such as plantations and human settlements. Walauwawatta-Waturana is a small swamp-forest patch with an extent of 12 ha located in Bulathsinhala, yet it supports a unique species assemblage including two point endemic species. The article provides an overview about the Walauwawatta-Waturana
Species are fundamental to biology, conservation, and environmental legislation; yet, there is often disagreement on how and where species limits should be drawn. Even sophisticated molecular methods have limitations, particularly in the context of geographically isolated lineages or inadequate sampling of loci. With extinction rates rising, methods are needed to assess species limits rapidly but robustly. Tobias et al. devised a points-based system to compare phenotypic divergence between taxa against the level of divergence in sympatric species, establishing a threshold to guide taxonomic assessments at a global scale. The method has received a mixed reception. To evaluate its performance, we identified 397 novel taxonomic splits from 328 parent taxa made by application of the criteria (in 2014‒2016) and searched for subsequent publications investigating the same taxa with molecular and/or phenotypic data. Only 71 (18%) novel splits from 60 parent taxa have since been investigated by independent studies, suggesting that publication of splits underpinned by the criteria in 2014–2016 accelerated taxonomic decisions by at least 33 years. In the evaluated cases, independent analyses explicitly or implicitly supported species status in 62 (87.3%) of 71 splits, with the level of support increasing to 97.2% when excluding subsequent studies limited only to molecular data, and reaching 100% when the points-based criteria were applied using recommended sample sizes. Despite the fact that the training set used to calibrate the criteria was heavily weighted toward passerines, splits of passerines and non-passerines received equally strong support from independent research. We conclude that the method provides a useful tool for quantifying phenotypic divergence and fast-tracking robust taxonomic decisions at a global scale.
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Although the avian family Anhingidae is unequivocally monophyletic, the number and relationships of the component species within the single genus (Anhinga) have long remained unclear. Here, we use extensive mitochondrial and nuclear DNA sequence data (8,878 bp) to show that four species should be recognized. Our fully resolved and well‐supported tree shows that the American Anhinga (Anhinga anhinga) is sister to the three Old World species, with the Oriental (A. melanogaster) and African (A. rufa) Darters sister within the Old World clade, which also includes the Australian Darter (A. novaehollandiae). We estimate that the divergence between the New World and Old World branches occurred 19–22 mya, with the Australian Darter separating from its Old World congeners 14–16 mya and the Oriental and African species splitting ~10 mya. The genus is yet another example of osteological conservatism in the Suliformes, which is comparable to that shown by the cormorants and shags. Nevertheless, the relationships we infer are congruent with recent plumage studies and are biogeographically plausible. We suggest that further investigation of the variation within the African and Australian Darters would be of interest.
The Indian Cormorant (Phalacrocorax fuscicollis) is a common avian piscivore that occurs throughout the Indian subcontinent and east to southern Vietnam. Its evolutionary relationships, however, have remained obscure, largely because of a lack of material available for either osteological or genetic analysis. Here we show using DNA-sequence data from both nuclear and mitochondrial genes that this species is sister to the allopatric Little Black Cormorant (P. sulcirostris), which occurs from Java in the west through southern Indonesia and New Guinea to Australia and New Zealand in the south. We estimate this split to have happened 2.5–3.2 million years ago, during the late Pliocene. We also report on genetic variation within the mitochondrial control region, which suggests that this part of the genome may be useful in investigating if there is genetic structure across the geographical range of the Indian Cormorant.
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Dinopium benghalense is one of the five species currently recognized in the old-world woodpecker genus Dinopium, which includes six subspecies or races. Sri Lanka had two subspecies of D. benghalense; D. b. jaffnense (Golden-back woodpecker) and D. b. psarodes (Red-backed Woodpecker). D. b. jaffenese is distributed in northern parts while the latter was in southern parts of the island. In the current world checklist of Bird life International, the D. b. psarodes has been elevated to a full species level; D. psarodes based on its plumage. Many colour variations can be observed within these Sri Lankan forms. Facial patterns and mantle colour are the key identification pointers, though actual intensity of the gold, yellows and red varies individually, making a detailed study of plumage an interesting undertaking for both the amateur birder and for the ornithologists alike. Here we document and validated basic plumage patterns and colour shown by the Sri Lankan Dinopium flamebacks. Seventy woodpeckers along a 430 km transect spanning across the island and 55 museum specimens were sampled. We evaluated 21 colour–based characters: Colour analyses were based on Munsell colour charts. We found scarlet, red, orange, golden yellow and olive-yellow forms in Dinopium complex in Sri Lanka. A clinal gradation is observed from North to South in these colour patterns.
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When two species or subspecies hybridize, the parental taxa may become more similar or follow new directions as alleles from one enter the novel genetic and ecological environment of the other. Here, we document hybridization between two Dinopium woodpeckers in Sri Lanka: two subspecies of Black-rumped Flameback woodpeckers (Dinopium benghalense jaffnense and D. b psarodes, recently considered as a full species Lesser Sri Lanka Flameback Dinopium psarodes). Hybridization has been suspected for 130 years. We describe eight different forms of hybrids, only two of which were known historically, and pairing patterns that indicate hybridization. The species and subspecies along with numerous hybrids have now become a hybrid swarm in northern Sri Lanka. Received 2 May 2014. Accepted 30 December 2014.
We analysed the distributions of fifty-eight avian sister-species pairs from the Indian region in order to determine the concordance of inter-species range boundaries with physiographic barriers in the region, and to delineate the degree to which the pattern of distribution of the species-pairs accords with the predictions of four models of geographic speciation. Fifty species-pairs exhibited range boundaries that were associated with one or more major environmental features of the Indian subcontinent: major river system (twenty), salt water passage (fifteen), mountain chain (ten), break in mountain chair (four), plains/mountain discontinuity (six). Among our Indian sample of sister-species pairs, we found examples showing a favourable fit to each of the four speciation models: dispersal model (twenty-five examples), vicariance model (eleven), refugial model (eight), parapatric model (six); eight examples could not be assigned with certainty. Support for the rarely-considered parapatric model is consistent enough to warrant further investigation of its possible importance in vertebrate speciation.
The hybrid zone between the Red- and Yellow-shafted Flickers has been stable on the United States Great Plains in historical times. This conclusion is based on multivariate comparisons of historical and contemporary collections from 18 locales. Adaptive speciation theory predicts that the hybrid zone should either become broader or narrower as a result of introgressive hybridization or reinforcement of premating isolating mechanisms. Neither of these predictions was borne out. Despite 10,000-13,000 years of hybridization, mating between subspecies remains indiscriminate. The data are also inconsistent with a dynamicequilibrium hypothesis wherein narrow hybrid zones are maintained by hybrid unfitness. According to this hypothesis, the hybrid zone would probably "flow" unless it was trapped by a population density trough. The hybrid zone does not appear to be associated with such a feature. The data are consistent with a bounded hybrid superiority theory of a hybrid zone, but this is more a question of survival in a process of elimination than a resounding corroboration.
Guide to virtually every tree likely to be encountered on the island, some 700 in total. Each is described in detail, covering morphology, leaf, flower and fruit, and each also has a line illustration of the leaf. There are notes on endemicity, geographical distribution, habitat, and uses.