Australian Aquatic Biological

Australian aquatic biodiversity research and consultancy

Central Highlands Burrowing Cray Engaeus affinis (Smith & Schuster 1913)

Engaeus affinis from a communal burrow, Healesville, Vic

Engaeus affinis from a communal burrow, Healesville, Vic

This species is endemic to Victoria with a relatively small distribution known at this time (estimated extent of occurrence of approximately 200 km2). Found in the upper Yarra, Acheron, Yea and Big Rivers. An area roughly from Kinglake to Eildon to Jamieson to Noojee to Hoddles Creek. Central Highlands Burrowing Cray Engaeus affinis has been assessed on the IUCN Red List as Data Deficient. 

Engaeus affinis, Healesville, Vic

Engaeus affinis, Healesville, Vic

It’s a robust species and at many sites relatively abundant. Typically, it’s a communal burrower, both type 2 & 3 burrows with multiple surface entrances (20 or so) over a square metre. Both fans shaped entrances and chimneys. Surface openings descend into large central burrows. Central burrows are relatively large in diameter (150 to 200 mm), typically water filled and tending horizontal and descending and converging into a larger chamber.

Engaeus affinis, Badger Creek, Vic

Engaeus affinis, Badger Creek, Vic

Typically, the easiest way to capture is to excavate down to the water level, usually from 200 to 600 mm deep. Once water is found, wait, (patience required), larger males will come to investigate the disturbance and you can grab them, otherwise, every 5 minutes or so, shove your hand down the burrow and feel around in the water. If you are lucky and have good feeling in your fingers you should be able to grab one every 5-10 minutes. That’s the way we collected the specimens for this article.

Burrow entrance, Badger Creek, Vic

Burrow entrance, Badger Creek, Vic

Those from Healesville were in a yellow clay on the slope beside a creek approximately 1.2 metres above the creek water height (7 metres from creek bank) but had water at 650 mm in the burrow system. Those from Badger Creek were in a fine silty material in a seepage area in the tree fern forest with water only 100 mm below ground level and over 100 m from Badger Creek.

Engaeus affinis, Badger Creek, Vic

Engaeus affinis, Badger Creek, Vic

Happy Yabbying

Cheers

Rob

Lowland Burrowing Crayfish Engaeus quadrimanus

Also known as “The Mernda Land Yabby” Engaeus quadrimanus (Clark 1936) is a relatively widespread and locally abundant species. It’s a lowland species generally found under 250 m a.s.l. from just north of Melbourne, east along the Victorian coast to just before the NSW border. Engaeus quadrimanus has been assessed as Least Concern on the IUCN Red List.

Engaeus quadrimanus - note the burrow entrance behind

Engaeus quadrimanus – note the burrow entrance behind

This specimen is from the west of the range. Collected from the bank of Fish Creek a tributary of the Tarwin River crossing Meeniyan-Promontory Rd, Fish Creek, Victoria.

A very robust and adaptable species that usually has large colonies with the area being riddled with burrows. Typically, burrows are round to oval in shape and open with excavated material at the entrance (see photo). In some areas they can create a pelleted chimney but for many areas it’s just an open hole in the ground as the excavated material has been washed away with flood waters. Burrows are type 2 and relatively basic with only 2-3 surface entrances descending to a horizontal corridor then a deeper burrow to water table. Typically most of the burrow system is flooded and typically they are individual burrows with both males and females having their own burrows. One of the keys to the species is that they are intersexed so hard to determine which are males and which females. Breeding season is autumn and they can be found sharing burrows together then. The species is extremely active during flood events and uses the creeks to migrate and find mates, etc.

Fish Creek

Fish Creek

For a similar article on this species and images from populations further east, go to: http://www.austcray.com/2015/09/engaeus-quadrimanus-from-cann-river-victoria/

Cheers
Rob

 

A New Spiny Crayfish in Western Drainage, NSW.

Project: 100007 started back in 2008 final draws to a closure. The project that started out as an unidentified Euastacus crayfish species has been found in western drainage of NSW has been finalized with the completion of the project going to press.

The New Euastacus species for NSW showing an unusual colour variation

The New Euastacus species for NSW showing an unusual colour variation

A scientific manuscript title; Euastacus sp. nov., a new giant spiny crayfish (Crustacea, Decapoda, Parastacidae) from the Great Dividing Range, New South Wales, Australia, by Robert B. McCormack & Shane T. Ahyong has been completed and submitted to the journal Zootaxa.

The New Euastacus is a true spiny crayfish with numerous large sharp spines

The New Euastacus is a true spiny crayfish with numerous large sharp spines

The new species is described from the upper Cudgegong River, New South Wales, Australia This new species occurs in the western drainage of the Great Dividing Range, and is most closely related to E. spinifer (Heller, 1865), which occurs on the eastern side of the range. The new species differs from E. spinifer by its considerably smaller maximum size, greater degree of thoracic spination loosely arrayed in three instead of two rows, genetic sequence divergence in COI and unusual colour variations.

The new species is small in size with the majority of the female population breeding each year

The new species is small in size with the majority of the female population breeding each year

Both Euastacus armatus and the new Euastacus species occur in the upper Cudgegong River and this has led to much confusion in the past. Recent research by Whiterod et al., 2016 indicates that the E. armatus population in the upper Cudgegong is a translocated population.

In our present study, we formally describe this new Euastacus species, increasing the number of species of Euastacus to 53.

Cheers
Rob McCormack

East Gippsland Survey Season Commences 2016

Euastacus crassus

Euastacus crassus upper Murray River

The high country of East Gippsland is a difficult area to survey as the window of opportunity is small. In summer it’s too hot and subject to bushfires and road closures. In winter, it’s too cold and the crayfish have retired to their deep burrows being extremely difficult to find. This just leaves the spring and autumn crayfish survey season.

Our surveys in East Gippsland are targeted to answer a number of questions we have concerning the species present and their distributions. Unfortunately, the more we research the more questions are raised and we don’t seem to be making much forward progress despite accumulating huge amounts of new information.

 

1st Survey

The first survey was conducted in March by Craig Burnes and Rob McCormack, of the upper Murray and upper Snowy River tributaries in the Victorian Alpine National Park.

New Euastacus crassus Little River

New Euastacus crassus Little River

They surveyed the start of the Murray River from its most eastern and southern point in the Alpine National Park of Victoria. They were looking for Euastacus rieki, Euastacus claytoni and Euastacus crassus which occur in tributaries of the Murray River further north. What they found most closely matched Euastacus crassus in morphology but had a gastric mill count closer to Euastacus claytoni. Morgan 1997 did record lower TAP counts from specimens further west from the Bogong High Plains but genetic analysis will be very interesting.

Gastric mill upper Murray River

Gastric mill upper Murray River

Craig and Rob also surveyed the adjoining drainages of the upper Snowy River. The Little, Suggan Buggan and Buchan rivers were surveyed providing comparative material. Specimens from the Little River a tributary of the Snowy River for example vary in morphology but the gastric mill more closely resembles the norm for Euastacus crassus.

Gastric mill upper Little River (Snowy Rv)

Gastric mill upper Little River (Snowy Rv)

Specimens collected from each drainage will be included in a broad genetics study including specimens from the Tambo River in Victoria and the new population of E. crassus discovered in the Shoalhaven drainage. Stay tuned for results.

For further information on Euastacus crassus from the upper Murray & Snowy rivers see http://www.austcray.com/2016/04/alpine-national-park-victoria-new-euastacus-crassus/

 

2nd Survey

Surveys of the eastern tributaries of the Snowy River have been completed and resulted in the redescription of Euastacus diversus.

Coughran J, McCormack RB and Fetzner Jr. JW (2015). Re-description of the Orbost spiny crayfish, Euastacus diversus Riek 1969 (Decapoda: Parastacidae), in eastern Victoria, Australia. Freshwater Crayfish 21(1): 185-197.

In that paper we identified the species occurring within the next drainage east – the Bemm River as being a potentially new species. This has generated a species specific project, requiring the surveying of the Bemm and adjoining eastern drainages.

As part of this project an ACP survey team gathered to survey the Arte River drainage a major tributary of the Bemm River. We hadn’t surveyed this river before so it was essential information needed as part of the project to help increase our knowledge base.

Andrew Lincoln, Craig Burnes, Rob McCormack, Joe Henderson, Jo Edwards, Jim Reside

The Team – Andrew Lincoln, Craig Burnes, Rob McCormack, Joe Henderson, Jo Edwards, Jim Reside

The team consisted of Andrew Lincoln, Craig Burnes, Rob McCormack, Joe Henderson, Jo Edwards and Jim Reside. We met up in Orbost and Kuark Forest to survey the tributaries of the Arte River.

Euastacus sp. Arte Rv - Spec 5737

Euastacus sp. Arte Rv – Spec 5737

We surveyed a large number of streams and were successful in finding Engaeus, Euastacus sp, and Euastacus kershawi. We were specifically targeting Euastacus sp and the specimens collected will be used for our morphological and genetics program for this species. Further surveys are needed in the other tributaries of the Bemm and adjoining drainages, hence, this project will continue for some time.

Euastacus sp. Arte River, Victoria

Euastacus sp. Arte River, Victoria. Spec 5739

My thanks to the team members who guided us through the back roads of the forest despite many of them being disused and overgrown.

The survey convoy held up by a blocked road

The survey convoy held up by a blocked road

Clearing the forest road

Clearing the forest road

The 3rd Survey

Was conducted by Craig Burnes and Rob McCormack of tributaries of the Cann and Genoa Rivers. This survey again created more questions than answers. We were expecting to find Euastacus bidawalus and we were successful in finding them with the ones we found matching the morphological description of E. bidawalus. Then however, we found specimens in the Genoa River catchment that did not match the current description. This is a dilemma, is this just morphological variation between populations 1 km apart or two separate species. Instead of answers again more questions and further research needed.

Euastacus bidawalus, Cann Rv, (Spec 5751)

Euastacus bidawalus, Cann Rv, (Spec 5751)

Euastacus sp, Genoa Rv, (Spec 5755)

Euastacus sp, Genoa Rv, (Spec 5755)

It’s always a pleasure investigating the East Gippsland forests and streams; we will be back as soon as we can to do it all over again.

Cheers

Rob McCormack

 

 

Orbost Spiny Crayfish paper finally published

Euastacus diversus from Ellery Creek (Brodribb drainage) showing 2 marginal squamal spines

Euastacus diversus from Ellery Creek (Brodribb drainage) showing 2 marginal squamal spines

Started in 2005 the quest to rediscover the Orbost Spiny Crayfish Euastacus diversus has been a long and intriguing journey cumulating in the publication of this paper.

This story began back in 1959 when one of Australia’s foremost expert on freshwater crayfish at that time, Edgar Riek, discovered this small freshwater crayfish species in the east Gippsland region of Victoria. Then in 1969 he described the species and named it Euastacus diversus. Since that day this crayfish has remained a rare and elusive species.

In 1986, the then current expert on the genus Euastacus, Gary Morgan, searched for this species but was unable to find any in the wild. As a consequence he redescribed the handful of original specimens collected by Riek in 1959 that are held at the Australian Museum. Gary Morgan’s detailed description, published in the Memoirs of the Museum of Victoria 30th May 1986, was the latest scientific publication on this species and forms the basis of all current information and opinions until now.

In 2005, the Australian Crayfish Project (ACP) was started, involving one of the largest projects researching freshwater crayfish ever seen in Australia. Between 2005 and 2007 we also failed to find any specimens of Euastacus diversus for the type locality general area 40 miles north of Orbost. Then in 2007 we changed our methods and successfully started finding more and more specimens. Up to 2011 a considerable number of E. diversus and other Euastacus species were found in the wild. The project has been very successful in finding this and other crayfish species, and large areas of southern NSW and eastern Victoria were systematically biologically surveyed specifically for freshwater crayfish. We found Euastacus specimens everywhere and most did not match the description for the known species leading to much confusion. However, genetic analysis by the Carnegie Museum of Natural History in the USA helped clarify the situation resulting in the thorough redescription of E. diversus and the discover of a number of new species.

Euastacus diversus redescription 2015

Euastacus diversus redescription 2015

The research culminated in this paper titled “Re-description of the Orbost Spiny Crayfish, Euastacus diversus Riek 1969 (Decapoda: Parastacidae), in Eastern Victoria, Australia” published in the journal “Freshwater Crayfish”. The paper redescribes Euastacus diversus to include the Bonang River crayfish (previously thought to be a new species).

The Bonang River crayfish from the most northern extent of distribution

The Bonang River crayfish from the most northern extent of distribution

The Bonang taxon represent a morphologically distinct population of Euastacus diversus that is genetically 1.95% divergent from the E. diversus type locality populations.

Euastacus diversus from Riddle Creek

Euastacus diversus from Riddle Creek

The research extends the distribution of the species to the Brodribb, Yalmy, Rodger and Bonang River drainages at elevations ranging from 350 – 950 m a.s.l., with an overall Extent of Occurrence of 465 km2. Research continues on E. diversus which will surely increase the Extent of Occurrence. Research also continues on the new Euastacus species and hopefully the first of the new species descriptions will be published later this year.

Citation:

Coughran J, McCormack RB and Fetzner Jr. JW (2015). Re-description of the Orbost spiny crayfish, Euastacus diversus Riek 1969 (Decapoda: Parastacidae), in eastern Victoria, Australia. Freshwater Crayfish 21(1): 185-197.

 

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