PHYLOGEOGRAPHY OF A NEW SPECIES OF COLLEMBOLA NEANURIDAE FROM TALLAGANDA STATE FOREST, NEW SOUTH WAL

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PHYLOGEOGRAPHY OF A NEW SPECIES OF COLLEMBOLA
(NEANURIDAE) FROM TALLAGANDA STATE FOREST, NEW
SOUTH WALES
Ryan Garrick and Paul Sunnucks Genetics
Department, La Trobe University, VIC. E-mail
r.garrick_at_latrobe.edu.au
Figure 1. The new species of Collembola, which
represents a new genus.
ABSTACT Based on a 650-bp region of the
mitochondrial cytochrome oxidase subunit I
(mtCOI) gene, an investigation into the
population-genetic structure of a
slime-mold-grazing giant springtail
(Collembola) (Fig. 1) has revealed strikingly
congruent phylogeographies between this species
and a co-distributed ferocious glue-spitting
velvet-worm (Onychophora). Despite contrasting
ecological roles, these taxa respect the same
biogeographic breaks, exhibit their greatest
mtCOI diversity in the same geographic region,
and share common genetic contact zones within
morphospecies. Historical vicariance events are
implicated as a particularly influential
process. These findings suggest a strong
influence of habitat upon genetic structure (c.f.
species biology). The distribution of genetic
diversity among members of the rotten log
community may have a consistent, predictable
spatial arrangement. Such information will
facilitate the prioritisation of areas for
conservation at Tallaganda State Forest, where
commercial forestry operations occur.
Figure 3. Phylogeography of a giant
collembolan.
BACKGROUND Saproxylic (dead wood dependent)
invertebrates Functionally important,
constitute a large proportion biodiversity in
forest ecosystems, yet are understudied. Many
species are undescribed, species distributions
are largely unknown, and almost no work has been
carried out on the genetic structure and
diversity of their populations. Forestry and
conservation of biodiversity Current
forestry practices result in (i) breaks in
spatial and temporal continuity among rotten log
habitats, and (ii) a reduction in dead wood
microhabitat diversity within logged areas (Fig.
2). Many log-dwelling invertebrates face local
and regional extinction owing to their inherently
poor dispersal abilities.   Forest
invertebrate biodiversity habitat-specific or
species-specific? The present research seeks
to guide conservation strategies. Through
determining whether geographic patterns of
population-genetic differentiation are driven by
the history of the habitats or by factors
peculiar to the type of organism, management
strategies that optimize conservation action can
be devised.
RESULTS Collembola mtCOI diversity Collembola
phylogeography 16 haplotypes, 4 major mtCOI
lineages. Phylogenetic breaks correspond with Up
to 7 sequence divergence. geographic regional
breaks with Most logs comprised of individuals
with remarkable precision (Fig. 3).
the same haplotype.

The four major lineages occur
in a
south-north succession,
from the most Comparative phylogeography
basal in the south to the most derived in
Striking congruence between the
north (Fig. 3). Collembola and velvet-worm
phylogeographies.
Four of the five putative
biogeographic regions corroborated by
Collembola molecular data (the fifth
region requires additional sampling).
MAIN FINDINGS Springtail vs. velvet-worm
phylogeography In spite of marked
species-specific differences (e.g. ecological
role, reproductive biology and population
demography), the two co-distributed invertebrate
taxa display striking phylogeographic
congruence.   Forest invertebrate biodiversity
habitat-specific or species-specific? The
saproxylic habitat appears to have a strong
influence on the spatial distribution of genetic
diversity. Historical climate change is
implicated as an important process driving
population differentiation (through vicariance),
leading to a consistent, predictable spatial
distribution of genetic diversity among diverse
log-dependent fauna. These findings hold great
promise for the conservation of biodiversity in
this ecologically important community.
Figure 2. Current forestry practices threaten
log-dependent fauna.
FUTURE DIRECTIONS Develop nuclear genetic
markers for Collembola to assess
population-genetic structure using multiple
independent loci. Increase sample size and
improve spatial representation. Investigate the
phylogeography of a co-distributed distantly
related new species of Collembola (Fig. 4) and
explicitly assess the degree of phylogeographic
congruence between these two rotten log
specialists
METHODS 124 collembola were collected from
25 rotten logs along an 80km transect which
encompassed 5 putative biogeographic regions
defined a priori on the basis of geographic and
vegetation characteristics and previous genetic
analysis of the velvet-worm Euperipatoides
rowelli. Individuals screened for mtCOI
sequence variation via SSCP. Representatives of
each haplotype were then sequenced. Phylogenetic
relationships were reconstructed using Maximum
Parsimony and Neighbour Joining methods.
Relationships were then related to the geography.
A qualitative assessment of the degree of
congruence between the Collembola and E. rowelli
phylogeography was made.
Figure 4. A co-distributed spiky collembolan.
ACKNOWLEDGEMENTS Dave Rowell (ANU) Penny
Greenslade (ANU) Noel Tait (MQU) Mike Westerman
(LTU) State Forests of New South Wales and
everyone from the Sunnucks lab.