The Wilson Journal of Ornithology 123(3):441—453, 2011 
PHYLOGENY AND TAXONOMIC REVIEW OF PHILIPPINE LOWLAND 
SCOPS OWLS (STRIGIFORMES): PARALLEL DIVERSIFICATION OF 
HIGHLAND AND LOWLAND CLADES 
HECTOR C. MIRANDA JR., 14 DANIEL M. BROOKS, 2 AND ROBERT S. KENNEDY 3 
ABSTRACT.—We constructed a phylogenetic hypothesis of the pattern of colonization of Philippine scops owls (Otus 
and Mimizuku). Two mitochondrial genes, ND2 and cytochrome h, were sequenced for 12 samples representing six 
Philippine endemic taxa: three endemic species, one of which has three endemic subspecies: and one endemic genus. 
Topology, branch length information, and sequence divergence were used to present the hypothesis for the pattern, 
direction, and sequence of island colonization events. Philippine scops owls arc in two well-supported dades, consistent 
with at least two independent colonization routes. One route is represented by the montane clade of Otus sunia, O. 
Inngicomis, and 0. minis, The other dude is represented by three subspecies of the lowland O. megalotis. The basal 
position of Mimizuku gurneyi relative to the megalotis dadc suggests early colonization of Mindanao. Branch lengths and 
sequence divergence data are congruent with die morphological differences among the megalotis races. The three races of 
megalotis differed in 15 of 16 morphological characters. Based on molecular and morphological evidence, we recognize the 
following Otus megalotis subspecies as lull species: Luzon Lowland Scops Owl (O megalotis), Mindanao Lowland Scops 
Owl (O. everetti), and Visayan Lowland Scops Owl (0. nigra rum). Wc also propose reassigning the Giant Scops Owl 
I Mimizuku gurneyi) to the genus Otus lor phylctic consistency. Received 20 November 2010. Accepted 15 April 2011. 
Archipelagos are interesting places to study 
phylogeography and evolution because open seas 
represent potential barriers to gene flow. The 
construction of robust species phylogenies in 
island archipelagos provides important insights 
to rates, patterns, and modes of species diversi¬ 
fication (Lovette and Bcrmingham 1999, Ricklefs 
and Bermingham 1999, Coyne and Price 2000, 
Barraclough and Nee 2001. Turelli et al. 2001, 
Jones and Kennedy 2008a). The Philippine 
Archipelago, comprising >7,000 islands, has high 
endemism and some of the most unique avifaunal 
lineages in the world (Mittermeier et al. 1999, 
Kennedy et al. 2000, Myers et al. 2000. Peterson 
2006). The archipelago is relatively recent in 
geological time (most islands are <35 million 
years ago. hereafter mya). and the chronology of 
oceanic island formations from sea floor tectonic 
ev ents and patterns of coalescence and fragmen¬ 
tation are well documented (Hall 1996, 1998. 
2002). These conditions provide investigators 
unique opportunities to test hypotheses to explain 
present patterns of species diversification. Recent 
phylogeographic studies of some vertebrate 
groups, such as rodents (Steppan et al. 2003, 
Department of Biology. Texas Southern University, 
3100 Cleburne Drive. Houston, TX 77004, USA. 
" Houston Museum of Natural Science. 5555 Hermann 
Park Drive. Houston, TX 77030, USA. 
Maria Mitchell Association. 4 Vestal Street. Nantucket. 
MA 02554. USA. 
4 Corresponding author; e-mail: mirandahc@tsu.edu 
Jansa el al. 2006). thrushes (Jones and Kennedy 
2008a, b), and bulbuls (Oliveros and Moyle 2010) 
have illuminated complex patterns of diversifica¬ 
tion within the Philippine Islands. We document 
the altitudinal pattern of colonization and examine 
the taxonomy of Philippine scops owls (Otus and 
Mimizuku ) using two mitochondrial genes with 
additional evidence from morphology. 
GEOLOGIC HISTORY OF THE 
PHILIPPINE ARCHIPELAGO 
The Tertiary and Quaternary geological history 
of the Philippine Archipelago has been well 
documented (Hall 1996. 1998, 2002). Extensive 
studies have also investigated the role of past 
episodic sea level fluctuations and climate 
changes that shaped the configuration of the 
islands and formation of distinct biogeographic 
regions (Heaney 1986, 1991, 2000; Heaney and 
Rickart 1990; Musser and Heaney 1992; Steppan 
et al. 2003: but see Jones and Kennedy 2008a). 
The Philippine Archipelago is considered 
geologically young with most land emerging from 
the sea floor <35 mya. The three distinct 
geological units that emerged and coalesced over 
the recent past are the Palawan-Mindoro, Greater 
Luzon, and Greater Mindanao blocks (Fig. 1). 
The Palawan-Mindoro block was a part of the 
mainland Southeast Asia continental shelf and 
broke away 30-35 mya. Palawan emerged about 
5 mya and was connected to northern Borneo, but 
not to other major islands of the Philippine 
Archipelago. Luzon Island emerged about JO- 
441 
