Research Article |
Corresponding author: Sarah Boyer ( boyer@macalester.edu ) Academic editor: Adriano Kury
© 2016 Katya Jay, Zachary Popkin-Hall, Michelle Coblens, Jill Oberski, Prashant Sharma, Sarah Boyer.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Jay KR, Popkin-Hall ZR, Coblens MJ, Oberski JT, Sharma PP, Boyer SL (2016) New species of Austropurcellia, cryptic short-range endemic mite harvestmen (Arachnida, Opiliones, Cyphophthalmi) from Australia’s Wet Tropics biodiversity hotspot. ZooKeys 586: 37-93. https://doi.org/10.3897/zookeys.586.6774
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The genus Austropurcellia is a lineage of tiny leaf-litter arachnids that inhabit tropical rainforests throughout the eastern coast of Queensland, Australia. The majority of their diversity is found within the Wet Tropics rainforests of northeast Queensland, an area known for its exceptionally high levels of biodiversity and endemism. Studying the biogeographic history of limited-dispersal invertebrates in the Wet Tropics can provide insight into the role of climatic changes such as rainforest contraction in shaping rainforest biodiversity patterns. Here we describe six new species of mite harvestmen from the Wet Tropics rainforests, identified using morphological data, and discuss the biogeography of Austropurcellia with distributions of all known species. With this taxonomic contribution, the majority of the known diversity of the genus has been documented.
Queensland, rainforest, biogeography, morphology, taxonomy
The mite harvestmen (order Opiliones, suborder Cyphophthalmi) are a globally distributed suborder of tiny (1.5–5 mm), cryptic arachnids that are extremely dispersal-limited, making them ideal for fine-scale historical biogeographic studies. Nearly all species are known from pristine leaf-litter habitats in tropical, subtropical, and temperate forests, with a few others from caves (
Distribution of all Austropurcellia species found throughout Queensland, Australia. Largest white box outlines the Wet Tropics World Heritage Area, shown in closer detail to the right. Smaller boxes within inset map represent groups of closely related species found within the Wet Tropics by
Prior to 2012, only five Austropurcellia species were known (four from the WT and one from Central Queensland). Thus, little was known about the evolutionary history of the genus and its diversity in the region. Subsequently,
Austropurcellia is an ancient lineage, and its evolutionary history has no doubt been shaped by the turbulent geological and climatic history of the Australian continent. Molecular dating suggests that Austropurcellia underwent initial diversification in the late Cretaceous (
The WT is considered to be a model system for studying biogeographic processes that shape rainforest diversity because it contains disproportionately large percentages of Australia’s fauna (despite comprising only 0.12% of the continent by area), as well as unusually high rates of endemism (
Mite harvestmen are known to have very low dispersal rates, with species even in well-surveyed areas generally found in only a few localities within a 50-km radius (
Here we present six new species of mite harvestmen from the WT that are morphologically distinct from other members of Austropurcellia. We identify several diagnostic characters that vary between groups of species whose ranges are geographically proximate, and use this information to form hypotheses about the new species’ phylogenetic relationships.
Specimens were hand-collected by the authors and colleagues in the WT of Queensland, Australia by sifting leaf litter during 2011-2015 and preserved in 95% ethanol. Additional specimens were provided by collections from Harvard’s
Collected specimens were examined for morphological differences using light microscopy and sorted into putative morphospecies. Due to their small size and highly conserved morphology, species-level differences are often only visible using an SEM. Therefore, males from different localities were examined on a scanning electron microscope (SEM). Only males possess characters that are diagnostic at the level of species.
Holotype specimens were photographed using an Olympus SZX10 light microscope driven by Leica Acquire software (Leica Microsystems) at multiple focal planes. Image series were integrated using Helicon Focus (Helicon Soft Limited). Specimens were placed in hand sanitizer for lateral images.
Paratype males chosen for SEM were dissected under the light microscope and mounted on stubs. One of each walking leg (I-III) as well as one palp and one chelicera were removed and mounted on a single stub. Both legs IV were mounted to provide a lateral and medial view of distinguishing features. One female leg IV was also mounted for comparison. Males were mounted ventrally on another stub to allow for close examination of the anal plate and scopula, and remounted for examination of dorsal ornamentation. Stubs were coated with gold-palladium alloy using a Denton Vacuum Desk III sputter coater and imaged using a JEOL JSM-6610LV SEM. Appendage measurements were made using the digital scalar tool included in the JEOL software package. New species were diagnosed based on several key character systems that are demonstrably informative in Austropurcellia taxonomy: male anal plate shape, scopula size and shape, tarsus IV segmentation and shape, and adenostyle shape (Fig.
SEM images for new species were edited to have a uniform black background using Adobe Photoshop CS6 Extended and compiled into plates using Adobe Illustrator CS6. ArcGIS 10.2.1 was used to create distribution maps for species.
All material examined is from Queensland, Australia.
Austropurcellia scoparia Juberthie, 1988
Austropurcellia absens Boyer & Popkin-Hall, 2015, A. acuta Popkin-Hall & Boyer, 2014, A. alata Boyer & Reuter, 2012, A. arcticosa Cantrell, 1980, A. barbata Popkin-Hall & Boyer, 2014, A. cadens Baker & Boyer, 2015, A. capricornia Todd Davies, 1977, A. clousei Boyer, Baker & Popkin-Hall, 2015, A. culminis Boyer & Reuter, 2012, A. daviesae Juberthie, 1989, A. despectata Boyer & Reuter, 2012, A. forsteri Juberthie, 2000, A. giribeti Boyer & Quay, 2015, A. scoparia Juberthie, 1988, A. sharmai Boyer & Quay, 2015, A. superbensis Popkin-Hall & Boyer, 2014, A. tholei Baker & Boyer, 2015, A. vicina Boyer & Reuter, 2012, A. woodwardi Forster, 1955.
Holotype. Male (
Paratypes. 3 males, 3 females, same collecting data as holotype,
1 female, Mt. Finnigan (sample 2, AR3), 15.816°S, 145.278°E, coll. Alex Riedel 28.iv.2014,
4 males, 5 females, 2 juveniles, Mt. Finnigan 37 km S Cooktown, 15.817°S, 145.283°E, coll. G. B. Monteith, D. Yeates, and D. Cook 22.iv.1982,
3 males, 1 female, Mt. Finnigan Summit, 15.817°S, 145.283°E, coll. G. B. Monteith 21.xi.1998,
Distinguished from congeners by very short, round scopula emerging from posterior quarter of fully granulated anal plate. Distinctive lack of granulation on sutures of dorsal scutum, including medial sulcus.
Pettalid with tergite VIII bilobed (Figs
Ozophores relatively conical, of type III sensu
Chelicerae (Fig.
Legs with all claws smooth, without ventral dentition or lateral pegs (Fig.
Austropurcellia finniganensis sp. n., paratype male and female,
Length measurements from male paratype of leg articles from proximal to distal (in mm): leg I [trochanter damaged], 0.59, 0.26, 0.43, 0.20, 0.40; leg II 0.26, 0.42, 0.25, 0.30, 0.15, 0.34; leg III [trochanter damaged], 0.48, 0.20, 0.33, 0.15, 0.31; leg IV [trochanter damaged], 0.50, 0.24, 0.39, 0.16, 0.35. Width measurements from male paratype of leg articles from proximal to distal (in mm): leg I [trochanter damaged], 0.18, 0.18, 0.17, 0.15, 0.20; leg II 0.17, 0.15, 0.16, 0.18, 0.13, 0.14; leg III [trochanter damaged], 0.18, 0.18, 0.19, 0.12, 0.14; leg IV 0.16, 0.21, 0.20, 0.21, 0.17, 0.18.
The specific epithet refers to the type locality, Mt. Finnigan.
Holotype. Male (
Paratypes. 5 males, 2 females, same collecting data as holotype,
2 females, 4 juveniles, McDowall Range 17 km N Daintree, 16.100°S, 145.333°E, coll. G. B. Monteith 27.xi.1985,
1 male, 2 females, Roaring Meg Creek 6 km W Cape Tribulation, 16.083°S, 145.4°E, coll. G. B. Monteith, D. Yeates, G. Thompson 5.x.1982,
1 female, Roaring Meg Creek 6 km W Cape Tribulation, 16.067°S, 145.400°E, coll. G. B. Monteith, D. Yeates, G. Thompson 5.x.1982,
Distinguished from congeners by convex anal plate with long, narrow scopula emerging from anterior quarter of anal plate and occupying a rectangular indented area for its entire length. Distinctive ungranulated areas cause ventral sutures to appear fused.
Pettalid with tergite VIII bilobed (Fig.
Ozophores relatively tall and conical, of type III sensu
Chelicerae (Fig.
Legs with all claws smooth, without ventral dentition or lateral pegs (Fig.
Austropurcellia fragosa sp. n., males and female. A male tarsus and metatarsus I,
Measurements from male paratype of leg articles from proximal to distal (in mm): leg I [trochanter damaged], 0.51, 0.17, 0.33, 0.18, 0.35; leg II [trochanter damaged], 0.38, 0.18, 0.27, 0.14, 0.30; leg III 0.14, 0.29, 0.18, 0.24, 0.12, 0.26; leg IV [trochanter damaged], 0.42, 0.23, 0.29, 0.17, 0.31. Width measurements from male paratype of leg articles from proximal to distal (in mm): leg I [trochanter damaged], 0.16, 0.16, 0.16, 0.14, 0.20; leg II [trochanter damaged], 0.15, 0.15, 0.17, 0.12, 0.12; leg III 0.16, 0.16, 0.15, 0.17, 0.12, 0.13; leg IV [trochanter damaged], 0.18, 0.17, 0.19, 0.14, 0.15.
The specific epithet is derived from the first declension form of fragōsus, from Latin, meaning “roaring” or “crashing”, a reference to the type locality, Roaring Meg Creek.
Holotype. Male (
Paratypes. 2 males, 1 female,
1 male, 3 females, Baldy Mountain Road, Herberton Range National Park, 17.267°S, 145.267°E, coll. D. Yeates and D. Cook 25.xi.1985.
4 males, 1 female, Baldy Mountain, 17.284°S, 145.432°E, coll. G. B. Monteith 10.x.1980,
1 male, CSIRO Trail (after hut), 17.108°S, 145.629°E, coll. S. L. Boyer, M. J. Coblens, K. R. Jay and P. P. Sharma 29.v.2014,
4 juveniles, Mt. Haig, 17.1°S, 145.583°E, coll. Taylor and Feehan 30.vi.1971,
1 male, 3 females, 5 juveniles, Mt. Haig, Lamb Range, 17.083°S, 145.6°E, coll. G. B. Monteith 25.ii.1997,
4 males, 2 females, 22 juveniles, Mt. Tiptree, 17.067°S, 145.617°E, coll. Taylor and Feehan 29.vi.1971,
Distinguished from congeners by an usually wide and long scopula emerging from anterior quarter of male anal plate and easily visible in lateral view. Anal plate is very flat compared to the more rounded anal plates of geographically proximate species such as A. tholei and A. despectata. Distinctive areas lacking granulation cause ventral sutures to appear fused. Male tarsus IV is fully bisegmented rather than partially bisegmented as in A. tholei and A. despectata.
Pettalid with tergite VIII bilobed (Fig.
Ozophores relatively conical, of type III sensu
Chelicerae (Fig.
Legs with all claws smooth, without ventral dentition or lateral pegs (Fig.
Austropurcellia megatanka sp. n., paratype male and female,
Measurements from male paratype of leg articles from proximal to distal (in mm): leg I 0.14, 0.48, 0.20, 0.30, 0.16, 0.39; leg II [trochanter damaged], 0.37, 0.17, 0.26, 0.13, 0.32; leg III [trochanter damaged], 0.30, 0.18, 0.23, 0.15, 0.26; leg IV [trochanter damaged], 0.36, 0.20, 0.28, 0.14, 0.32. Width measurements from male paratype of leg articles from proximal to distal (in mm): leg I [trochanter damaged], 0.15, 0.17, 0.16, 0.14, 0.19; leg II [trochanter damaged], 0.14, 0.16, 0.17, 0.12, 0.13; leg III 0.18, 0.15, 0.15, 0.16, 0.12, 0.11; leg IV 0.16, 0.17, 0.16, 0.18, 0.14, 0.14.
The specific epithet, a noun in apposition, honors a Mitsubishi Pajero four-wheel drive vehicle, nicknamed ‘Big Tank,’ which made it possible to access various remote localities in the WT, including the type locality of A. megatanka sp. n.
Holotype. Male (
Paratypes. 1 male, 1 female, same collecting data as holotype,
1 male, Mt. Edith Summit, 17.093°S, 145.622°E, coll. G. B. Monteith 8.iv.2014,
1 male, Davies Creek Road, 17.050°S, 145.600°E, coll. G. B. Monteith and G. Thompson 17.xii.1989,
1 male, Chujeba Peak Summit, 16.936°S, 145.657°E, coll. G. B. Monteith and G. Thompson 14-16.xii.1989,
4 males, 1 female, 1 juvenile, Mount Williams Summit, 16.917°S, 145.667°E, coll. G. B. Monteith 28.xi.1997,
1 male, 3 females, 1 juvenile, Mount Williams, 16.917°S, 145.667°E, coll. G. B. Monteith 28.xi.1997,
1 male, 1 female, 2 juveniles, Mount Williams, 16.917°S, 145.667°E, coll. G. B. Monteith and H. Janetzki 3.xii.1993,
Distinguished from congeners by an unusually wide scopula emerging from anterior margin or anterior quarter of male anal plate and covering entire width of anal plate. Closely resembles A. megatanka sp. n., due to full scopula covering most of anal plate, but distinguished from A. megatanka by differences in scopula shape and ubiquity of ornamentation on opisthosomal sternites.
Pettalid with tergite VIII bilobed (Fig.
Ozophores tall and conical, of type III sensu
Chelicerae (Fig.
Legs with all claws smooth, without ventral dentition or lateral pegs (Fig.
Austropurcellia monteithi sp. n., paratype male and female,
Measurements from male paratype of leg articles from proximal to distal (in mm): leg I 0.15, 0.50, 0.27, 0.38, 0.19, 0.43; leg II 0.17, 0.39, 0.19, 0.31, 0.12, 0.34; leg III [trochanter damaged], [femur damaged] 0.20, 0.25, 0.11, 0.27; leg IV [trochanter damaged], 0.41, 0.23, 0.33, 0.13, 0.37. Width measurements from male paratype of leg articles from proximal to distal (in mm): leg I [trochanter damaged], 0.18, 0.18, 0.17, 0.15, 0.22; leg II [trochanter damaged], 0.15, 0.16, 0.17, 0.13, 0.14; leg III [trochanter damaged], 0.18, 0.17, 0.18, 0.12, 0.13; leg IV [trochanter damaged], 0.20, 0.17, 0.19, 0.17, 0.16.
The specific epithet is a tribute to the legendary Queensland field biologist Geoff Monteith for his invaluable knowledge of Wet Tropics entomology, which guided much of our fieldwork. The authors also wish to recognize his outsize generosity and hospitality to visiting researchers. In addition, he collected many of the specimens used in this study, including the holotype for A. monteithi sp. n.
Holotype. Male (
Paratypes. 10 males, 19 females, 24 juveniles, same collecting data as holotype,
2 males, 2 females, Black Mountain 17 km ESE Julatten, 16.650°S, 145.483°E, coll. G. B. Monteith, D. Yeates, and D. Cook 29.iv.1982, S 2302,
Distinguished from congeners by lack of scopula on the male anal plate, a trait shared only with A. absens. Anal plate is flat and entirely ungranulated; A. absens anal plate is convex, bilobed, and mostly granulated.
Pettalid with tergite VIII bilobed (Fig.
Ozophores relatively conical, of type III sensu
Chelicerae (Fig.
Legs with all claws smooth, without ventral dentition or lateral pegs (Fig.
Austropurcellia nuda sp. n., males and female. A male tarsus and metatarsus I,
Measurements from male paratype of leg articles from proximal to distal (in mm): leg I 0.18, 0.52, 0.20, 0.39, 0.14, 0.41; leg II 0.15, 0.41, 0.19, 0.33, 0.14, 0.37; leg III [trochanter damaged], 0.37, 0.20, 0.29, 0.23, 0.32; leg IV 0.19, 0.44, 0.19, 0.35, 0.16, 0.39. Width measurements from male paratype of leg articles from proximal to distal (in mm): leg I 0.20, 0.16, 0.17, 0.16, 0.14, 0.20; leg II 0.18, 0.15, 0.15, 0.15, 0.12, 0.13; leg III [trochanter damaged], 0.17, 0.16, 0.19, 0.13, 0.14; leg IV 0.18, 0.19, 0.18, 0.18, 0.15, 0.17.
The specific epithet is derived from the first declension form of nūdus, from Latin, meaning “bare” or “naked”, a reference to diagnostic absence of the scopula or ornamentation of the anal plate in this species.
Holotype. Male (
Paratype. 1 female, Rossville, Bloomfield (sample 2B, AR2), 15.792°S, 145.302°E, coll. Alex Riedel 1.v.2014,
1 male, 2 females, Rossville, Bloomfield (sample 2, AR1), 15.792°S, 145.302°E, coll. Alex Riedel 29.iv.2014,
Distinguished from congeners by flat anal plate granulated anteriorly, with very short and round scopula emerging from posterior third of plate. Lobes of tergites VIII and IX rounded and prominent in dorsal view; absence of granulation in junction of the anal plate, the lobes of tergite VIII, and the dorsal scutum. Closely resembles A. finniganensis, but distinguished by its larger body size (0.4 mm longer, 0.2 mm wider).
Pettalid with tergite VIII bilobed (Fig.
Ozophores relatively conical, of type III sensu
Chelicerae (Fig.
Legs with all claws smooth, without ventral dentition or lateral pegs (Fig.
Measurements from male paratype of leg articles from proximal to distal (in mm): leg I 0.28, 0.64, 0.25, 0.48, 0.23, 0.46; leg II 0.22, 0.49, 0.25, 0.39, 0.16, 0.42; leg III 0.17, 0.42, 0.25, 0.35, 0.20, 0.39; leg IV 0.22, 0.61, 0.29, 0.44, 0.25, 0.41. Width measurements from male paratype of leg articles from proximal to distal (in mm): leg I 0.23, 0.21, 0.21, 0.20, 0.17, 0.23; leg II 0.21, 0.19, 0.19, 0.20, 0.15, 0.15; leg III 0.22, 0.21, 0.20, 0.20, 0.15, 0.16; leg IV 0.25, 0.23, 0.24, 0.25, 0.21, 0.20.
This species is named after Alex Riedel, the German entomologist who provided us with several collections of animals from key localities, including Mount Finnigan.
To develop Austropurcellia further as a system for studying WT biodiversity and biogeography, it is critical to describe and map the diversity of these cryptic, dispersal-limited arachnids. Significant progress has been made toward this aim; with the six new Austropurcellia species described here in addition to other recent work (
With a greater knowledge of the diversity of Austropurcellia comes greater challenge in diagnosing the genus, as previously discussed by
Differences in morphological features within the genus can provide insight into evolutionary relationships, especially in the context of geographic distributions of character states. For example,
Ventral posterior morphology and anal plate of all seven species from the northernmost WT. Three new species are shown on left, with three previously described species on right. A A. finniganensis from Mt. Finnigan,
Ventral posterior morphology and anal plate of all five species from the north-central WT and one species from the southern WT (A. clousei). Two new species are shown on top row, with four previously described species below. A A. monteithi, from Kahlpahlim Rock (Lambs Head) Trail trailhead,
Ventral posterior morphology and anal plate of all eight species from the central WT uplands. One new species is shown alongside seven previously described species. A A. megatanka from Baldy Mountain Road,
Fourth tarsus of male in lateral (external) view. A A. articosa from Dubuji Boardwalk,
Further defining characters that vary significantly between species include the size, position, and shape of both the anal plate and the scopula (Figs
While this pattern of geographic distributions of shared characters states suggests closer relationships of geographically proximate species, an alternative interpretation is that unrelated species in certain regions of the WT have experienced morphological convergence. However,
Two of the new species described here have already been included in a recent molecular phylogenetic analysis (
The other species whose phylogenetic relationships have already been investigated is A. monteithi sp. n., which is known from five localities throughout the Lamb Range (Davies Creek, Chujeba Peak summit, Mt. Edith summit, Mt. Williams summit, and the Kahlpahlim Rock trail), geographically placing this species in the north-central WT (Fig.
A. finniganensis sp. n., A. fragosa sp. n., and A. riedeli sp. n. all have distributions in the northernmost WT (Fig.
The WT is an important system for studying patterns and causes of rainforest endemism in both vertebrates and invertebrates.
These predictions, and the postulated covariance of geographic distance, morphology, and phylogenetic relatedness in Cyphophthalmi more broadly, should be tested in the future using multilocus molecular phylogenies including the new species of Austropurcellia described herein. Such an approach would enable quantification of phylogenetic signal inherent to male morphological characters such as scopula and adenostyle shape, toward integrative taxonomy of mite harvestmen. Two putative new species from the WT remain undescribed due to incomplete collections and a lack of sufficient data, both in terms of morphology and DNA; however, we are confident that the majority of Queensland’s mite harvestmen diversity has now been documented. As we continue to approach complete species-level sampling of Austropurcellia’s extant diversity, we anticipate this genus will serve as robust model system to test hypotheses of how climatic and geologic changes in the WT have affected the distribution of genetic diversity, and how such processes leave their signature in the evolutionary history of Queensland’s paleoendemic fauna.
We thank Geoff Monteith, Kieran Aland, and Alex Riedel for their collecting efforts. Jeff Thole provided invaluable technical support for SEM work. Rachel Quay and Macalester students enrolled in the Spring 2015 iteration of Biology 476: Research in Biodiversity and Evolution (Mito Imagawa, Joanne Johnson, Kaelyn Lemon, Kenji Shoemaker, and Mo Usavage) provided help with SEM imaging and discussion of the project. We also thank curators who lent material: Gonzalo Giribet (Harvard