Western Burrowing Cray, Engaeus merosetosus

November 26, 2015RobertFeatured, News
Engaeus merosetosus

Engaeus merosetosus

Engaeus crayfish are known as the burrowing or terrestrial crayfish. They are all small species usually under 70 mm head to tail and some species can be found well away from water in suburban lawns or the sides of mountains. There are 35 species found in Australia with 23 of those found in Victoria.

Waurn Ponds Creek, Victoria

Waurn Ponds Creek, Victoria

Pierre Horwitz in 1990 described Engaeus merosetosus with the holotype from Waurn Ponds in Victoria. The species occurs predominantly in the Geelong-Ballarat region, Victoria, Australia. It has been found in the upper reaches of the Werribee River and just across the Great Dividing Range in the upper reaches of the Loddon and Tullaroop drainages (Horwitz 1990).

Western Burrowing Cray Engaeus merosetosus

Western Burrowing Cray Engaeus merosetosus

Engaeus merosetosus has been assessed as Least Concern by the IUCN. This species is relatively broadly distributed, and there is no evidence that it is experiencing declines at the present time. This species has an estimated extent of occurrence of 5,292 km2 (IUCN 2015).

Berried Female Engaeus merosetosus

Berried Female Engaeus merosetosus

Horwitz 1990 did not record any berried females so the discovery of this berried female (44 eggs, 5.31 grams, 17.22 mm OCL) from Waurn Ponds Creek was a lucky find. The creek was low with just scattered puddles. Burrows were abundant most quite deep and all seemed water filled at least 200 mm down.

Engaeus merosetosus burrow

Engaeus merosetosus burrow

 

References and Further Reading

Horwitz, P. (1990). A taxonomic revision of species in the freshwater crayfish genus Engaeus Erichson (Decapoda: Parastacidae). Invertebrate Taxonomy 4: 427‐614.

IUCN Citation: Doran, N. and Horwitz, P. 2010. Engaeus merosetosus. The IUCN Red List of Threatened Species 2010: e.T153749A4540433. http://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T153749A4540433.en. Downloaded on 23 November 2015.

 

The Burrowing Crayfish Engaeus lyelli

November 26, 2015RobertFeatured, News

Engaeus crayfish are known as the burrowing or terrestrial crayfish which are generally all very small species usually under 70 mm head to tail. Engaeus lyelli has a widespread distribution and is considered the largest of all the Engaeus species. The large size and taxonomy of the species has led to much consternation and various authors have disagreed with its designation and affinities. Gan et al 2014 ran he complete mitogenome of the Australian land crayfish Engaeus lyelli to help clarify the situation.

Engaeus lyelli Spec 2875 Eildon, Vic

Engaeus lyelli Spec 2875 Eildon, Vic.

Thirty five described Engaeus species are found in Australia with twenty three of those found in Victoria. The Australian Crayfish Project (ACP) is researching all these species and E. lyelli has been under research for the last 8 years.

Engaeus lyelli Spec 2261 Nilahcootie, Vic

Engaeus lyelli Spec 2261 Nilahcootie, Vic

Horwitz 1990 redescribed the species and stated: The largest male found was 28.7 mm carapace length. Mature females ranged from 18.8 to 32.4 mm carapace length. The largest non-reproductive female was 27.7 mm carapace length. Horwitz 1990 did not record any berried females so the discovery by the ACP of females with eggs greatly increases the knowledge base on this species. This female from the Seymour area in November 2015 has 114 eggs, weighs 16.66 grams with an OCL 30.45 mm has eggs 2.5 mm long and 1.9 mm wide.

Engaeus lyelli, Spec 5629, Pukapunyal, Vic

Engaeus lyelli, Spec 5629, Pukapunyal, Vic

Engaeus lyelli has been assessed as Least Concern by the International Union for the Conservation of Nature and Natural Resources (IUCN). Although this species has a relatively restricted range, with an estimated extent of occurrence 11,200 km2, it is not impacted upon by any major threat processes. Monitoring of the population is suggested as habitat loss and degradation occurs within parts of its range, and climate change may pose a significant future threat to this specie. (IUCN 2015)

Engaeus lyelli, Spec 5633, Pukapunyal, Vic

Engaeus lyelli, Spec 5633, Pukapunyal, Vic

The IUCN states under distribution: This species is endemic to Victoria, Australia. It is most commonly found north of the Great Dividing Range from the Grampian Ranges in the west to near Myrtleford in the east, and it does not appear to extend far from the foothills of the Great Dividing Range in Victoria (although its northwards range has not been thoroughly investigated). The distribution is characterized by distinct gaps in its range, with gaps occurring between Moyston and Beaufort, in the Lerderderg River drainage region, between Ballarat and Daylesford, and in the Seymour-Yea region (although this gap may be due to insufficient sampling) (Horwitz 1990).

Engaeus lyelli, Spec 892, Granpians, Vic

Engaeus lyelli, Spec 892, Granpians, Vic

Engaeus lyelli is a riparian zone species found along the sides of creeks, billabongs and dams. It is also found in close proximity to other Genera like Cherax, Geocharax and juvenile Euastacus freshwater crayfish. Specimens are typically collected from their burrows by digging, however when no other crayfish species are present they can be collected by scoop net from ponds and dams in relatively high numbers. Burrows have an open entrance, usually 2-3 surface entrances along the sides of the water body, entrances are typically above the water line but these are in high water level fluctuation areas, have several subsurface burrows that travel down into the water table and all burrows contained water at the bottom. Most burrows sampled were relatively new burrows with fresh material at the surface, however most animals were captured 350-500 mm deep so not exceptionally deep on the scheme of things.

Engaeus lyelli pond, Pukapunyal, Vic

Engaeus lyelli pond, Pukapunyal, Vic

Engaeus lyelli burrows along edge of pond Pukapunyal, Vic

Engaeus lyelli burrows along edge of pond Pukapunyal, Vic

References & Further Reading

Doran, N. and Horwitz, P. 2010. Engaeus lyelli. The IUCN Red List of Threatened Species 2010: e.T153693A4532851. http://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T153693A4532851.en. Downloaded on 22 November 2015.

Horwitz, P. (1990). A taxonomic revision of species in the freshwater crayfish genus Engaeus Erichson (Decapoda: Parastacidae). Invertebrate Taxonomy 4: 427‐614.

DOI:10.3109/19401736.2014.908361Han Ming Gana*, Mun Hua Tana, Yin Peng Leea, Mark B. Schultzb & Christopher M. Austin. The complete mitogenome of the Australian land crayfish Engaeus lyelli (Clark 1936) (Crustacea: Decapoda: Parastacidae)

ACP DATA BASE

Collection GPS Coordinates and specimem information is only available to ACP Members to

view the collection data base for E. lyelli “CLICK HERE”  

Excel database spreadsheet

 

Engaeus quadrimanus from Cann River, Victoria

September 30, 2015RobertFeatured, News
Engaeus quadrimanus

Engaeus quadrimanus

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 coast to just before the NSW border.

Engaeus quadrimanus

Engaeus quadrimanus

Found along permanent creek and stream margins, swamps, seepages, drains and ephemeral creek beds. Found under dense scrub/forest to roadside drains and open sky backyards.

Engaeus quadrimanus

Engaeus quadrimanus

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. Many areas don’t have excavated material at the entrance as its been washed away with flood waters.

Engaeus quadrimanus

Engaeus quadrimanus

The species is extremely active during flood events and uses the creeks to migrate and find mates, etc. These specimens are from the Cann River region of Victoria.

Cheers

Rob McCormack

If you have enjoyed this article and our research please contribute financially to the research. Over $300 in fuel for the survey vehicles was expended on this project-we freely give our time but assistance with costs would help-even just a few dollars is gratefully accepted. To contribute less than $10 just change the quantity from 1 to say 0.5 for $5, if however, you have a spare $10K that would be enough to finish this research project and very gratefully accepted. To contribute “CLICK HERE”

Engaeus mairener

March 20, 2015RobertFeatured, News
Engaeus mairener

Engaeus mairener

I’m not familiar with the Tasmanian Engaeus but as per my Australian Engaeus bible (Horwitz, 1990) this species keys out as Engaeus mairener – if anyone has any other thoughts, please let me know as this is one of my first tastes of Tassie Engaeus.

The area (Tributary Little Pipers River, crossing Bridport Rd) was riddled with burrows

The area (Tributary Little Pipers River, crossing Bridport Rd) was riddled with burrows

Engaeus mairener Burrows

Engaeus mairener Burrows

This species is endemic to north-eastern Tasmania, and seemingly abundant. Burrows were close to each other (2-3/m2) with the areas where they occurred being riddled with burrows.

Dig the above burrow 600 mm and find this Engaeus mairener at the base

Dig the above burrow 600 mm and find this Engaeus mairener (18.75 mm OCL) in a small chamber at the base

Burrows tops were not the high chimney type but just a small mound of excavated material, we generally only excavated newly constructed burrows with fresh material at the burrow mouth (good chance of getting a crayfish). Most burrows had 2 surface entrances leading to a deep burrow that lead to either a small water filled chamber or just a water filled burrow with the crayfish crammed into the base.

Engaeus mairener burrows on the side of dry creek be

Engaeus mairener burrows on the side of dry creek bed

The burrow top

The burrow top

Take the top of the burrow off

Take the top of the burrow off

Dig 700 mm deep and find this Engaeus mairener crammed in the bottom

Dig 700 mm deep and find this Engaeus mairener crammed in the bottom

Most of the burrows I dug were in or along the sides creek beds, all were currently dry on the surface but there was water in all the burrow base excavated. Both clay and soil seemed to be suitable for the species and tea trees were typical in the burrow areas we collected crayfish from.

Reference

Horwitz, P. (1990). A taxonomic revision of species in the freshwater crayfish genus Engaeus Erichson (Decapoda: Parastacidae). Invertebrate Taxonomy 4 (3): 427–614. doi:10.1071/IT9900427

If you enjoyed this post then please make a contribution, please note that no one paid us to write this article, no one paid us to travel to Tassie, no one paid us to catch these critters, it’s all done at our own personal expense as a volunteer on the ACP. A contribution from you could pay for fuel in the car and allow us to do more towards increasing the knowledge base on our endemic crayfish species and assist in their, and their fragile habitat conservation. Please contribute – just a few dollars makes a significant contribution!

 

The Burrowing Crayfish Engaeus fossor

March 4, 2015RobertFeatured, News
Engaeus fossor

Engaeus fossor (Male, 25.07 mm OCL)

During a recent trip to Tasmania I had the pleasure of seeking some freshwater crayfish between looking at the local tourist attractions.  As per Horwitz 1990 this looks like Engaeus fossor, if anyone thinks otherwise please let me know.

The Burrowing Crayfish Engaeus fossor

The Burrowing Crayfish Engaeus fossor (Male, 31.06 mm OCL)

This burrowing crayfish is endemic to Tasmania, and has the widest distribution of all Tasmanian endemic Engaeus species (Horwitz 1990). These animals are from wet swampy areas along the side of Botanical Creek in the Forest Reserve at Strahan, Tasmania.

Hogarth falls

Hogarth falls

Access was gained at The Peoples Park, on the way to Hogarth Falls. Hogarth Falls is a local tourist attraction and well worth the short walk through the reserve.

Botanical Creek (upstream)

Selfie in Botanical Creek (upstream)

 

Botanical Creek upstream of the falls

Botanical Creek upstream of the falls

I hiked about a kilometre past the falls (about the best I could do in difficult terrain) and checked out the creek expecting to find some Astacopsis in the stream. Unfortunately, as a tourist and unprepared I just clamber down the ravine, stripped off my clothes and hopped into the stream to turn rocks. This proved less than satisfactory as the rocks were all extremely smooth and slime covered with razor sharp edges. You would step barefoot on a slimey, smooth sloping surface and slide down onto the razor edge of the next rock, anyway, after about 3 minutes I abandoned this idea as although only 1 km (took me 40 minutes) off the beaten track there was no sign that anyone had been that way in the last year so not a good place to have a whoopsie by yourself. I climbed back out of this quite nice looking stream (looking more like an albino walrus I’m sure) and tried to get my clothes back on before the leaches latched onto my more sensitive parts.

Engaeus fossor chimney burrow

Engaeus fossor chimney burrow

In the fading light I headed back downstream to check out the Engaeus burrows I saw on the way in.

Typical E. fossor chimney burrow

Typical E. fossor chimney burrow

You can see burrows beside the walking track from the park to the falls in any of the wet swampy areas and sides of the creek. Burrows have a chimney with mud/soil stacked high in a chimney formation.

Burrows were everywhere if the ground was moist

Burrows were everywhere if the ground was moist

The burrows have 3 to 5 surface entrances that are all connected and run parallel to the surface with a deeper burrow heading downward. I never found the base of the burrow system so don’t know how deep they went, but over 700 mm. Burrows were into the water table that was high only 150-200mm below the surface. The specimens I collected were all captured by stealth and brute force. All specimens were captured in the soft muddy burrows by approaching the burrow quietly without vibration, and quickly cramming my hand down the burrow and along the corridors until I surprised the animal that was getting ready to defend its turf and repel invaders. If I didn’t catch them off guard and get them within the first 30 seconds they would retreat down the burrow system and disappear into the depths, never to be captured.

Engaeus fossor, male, 25.07 mm OCL.

Engaeus fossor, male, 25.07 mm OCL.

 

Reference

Horwitz, P. (1990). “A taxonomic revision of species in the freshwater crayfish genus Engaeus Erichson (Decapoda: Parastacidae)”. Invertebrate Taxonomy 4 (3): 427–614. doi:10.1071/IT9900427