Gramastacus lacus, McCormack, Robert B., 2014

McCormack, Robert B., 2014, The eastern swamp crayfish Gramastacus lacus sp. n. (Decapoda, Parastacidae) a new species of freshwater crayfish from coastal New South Wales, Australia, ZooKeys 398, pp. 53-67 : 55-61

Gramastacus lacus sp. n. Figures 1-3

Material examined.

HOLOTYPE: AM P.89665, male, 18.63 mm OCL, 5.07 grams, Boomeri Swamp behind Boomeri camp ground, off Old Gibber Road, Myall Lakes National Park, 32.50910°S, 152.32143°E, altitude 12 m, 21 September 2012, R.B. McCormack.

ALLOTYPE: AM P.89663, berried female, 16.86 mm OCL, 3.17 grams, type locality, 21 September 2012, R.B. McCormack.

PARATYPES: AM P.89664, male, 17.62 mm OCL, 4.55 grams, type locality, 21 September 2012, R.B. McCormack. AM P.89666, berried female, 14.23 mm OCL, 2.06 grams, type locality, 21 September 2012, R.B. McCormack. AM P.89660, male, 20.22 mm OCL, 7 grams, tributary of Boolambayte Creek crossing Violet Hill Rd, Boolambatye, 32.41893°S, 152.28788°E, altitude 21 m, 19 August 2009, R.B. McCormack and S. Pavescki. AM P.89661, male, 16.76 mm, OCL, 4 grams, tributary Pourmalong Creek, under power lines, off Wyee Road, Wyee, 33.12770°S, 151.47438°E, altitude 36 m, 23 August 2009, R.B. McCormack. AM P.89662, male, 17.36 mm OCL, 4 grams, wetland swamp, Wamberal, 33.40927°S, 151.45890°E, altitude 7 m, 10 June 2010, R.B. McCormack.

Other material examined.

CMNH 37973.83, female, 14.47 mm OCL, Myall Lakes, May 2008, R.B. McCormack and K. Dawkins. CMNH 37973.84, male, 17.75 mm OCL, Myall Lakes, May 2008, R.B. McCormack and K. Dawkins. AM P.78514, Smiths Lake, May 1970, J. Paxton. ACP 179, male, 19.36 mm OCL, Myall Lakes, August 2005, R.B. McCormack. ACP 180, berried female, 15.27 mm OCL, Myall Lakes, August 2005, R.B. McCormack. ACP 181, male, 16.79 mm OCL, Myall Lakes, August 2005, R.B. McCormack. ACP 806, male, 2 g, 13.96 mm OCL, Myall Lakes, August 2007, R.B. McCormack. ACP 1147, male, 17.7 mm OCL, Budgewoi Lake, April 2008, R.B. McCormack. ACP 1148, male, 17.85 mm OCL, Myall Lakes, April 2008, R.B. McCormack. ACP 1169, male, 2 g, 14.65 mm OCL, Myall Lakes, May 2008, R.B. McCormack, K. Dawkins. ACP 1170, female, 2 g, 16.54 mm OCL, Myall Lakes, May 2008, R.B. McCormack, K. Dawkins. ACP 1171, male, 2 g, 14.65 mm OCL, Myall Lakes, May 2008, R.B. McCormack, K. Dawkins. ACP 1172, male, 3 g, 15.7 mm OCL, Myall Lakes, May 2008, R.B. McCormack, K. Dawkins. ACP 1591, male, 14.06 mm OCL, Lake Macquarie, November 2008, R.B. McCormack. ACP 1598, female, 9.17 mm OCL, Lake Macquarie, November 2008, R.B. McCormack. ACP 1628, male, 13.06 mm OCL, Lake Macquarie, November 2008, R.B. McCormack. ACP 1630, male, 12.13 mm OCL, Lake Macquarie, November 2008, R.B. McCormack. ACP 1651, male, 14.7 mm OCL, Lake Macquarie, December 2008, R.B. McCormack, S. Pacevski, J. Moylan, T.A. Moylan. ACP 1652, male, 13.38 mm OCL, Lake Macquarie, December 2008, R.B. McCormack, S. Pacevski, J. Moylan, T.A. Moylan. ACP 2286, female, 3 g, 16.7 mm OCL, Myall Lakes, August 2009, R.B. McCormack, S. Pacevski. ACP 2300, berried female, 3 g, 16.74 mm OCL, Lake Macquarie, August 2009, R.B. McCormack. ACP 2306, female, 3 g, 15.88 mm OCL, Lake Macquarie, August 2009, R.B. McCormack. ACP 2307, berried female, 4 g, 17.56 mm OCL, Lake Macquarie, August 2009, R.B. McCormack. ACP 2309, berried female, 2 g, 15.21 mm OCL, Lake Macquarie, August 2009, R.B. McCormack. ACP 2313, female, 7 g, 21.32 mm OCL, Myall Lakes, August 2009, R.B. McCormack. ACP 2318, berried female, 1 g, 12.3 mm OCL, Myall Lakes, September 2009, R.B. McCormack. ACP 2349, male, 11.99 mm OCL, Smiths Lake, September 2009, R.B. McCormack. ACP 2354, female, 9.2 mm OCL, Wallis Lake, September 2009, R.B. McCormack. ACP 2363, male, 11.79 mm OCL, Wallis Lake, September 2009, R.B. McCormack. ACP 2368, female, 9.08 mm OCL, Wallis Lake, September 2009, R.B. McCormack. ACP 2369, female, 11.27 mm OCL, Wallis Lake, September 2009, R.B. McCormack. ACP 2376, female, 11.72 mm OCL, Wallis Lake, September 2009, R.B. McCormack. ACP 2378, berried female, 1 g, 13.4 mm OCL, Myall Lakes, September 2009, R.B. McCormack. ACP 2387, berried female, 2 g, 13.08 mm OCL, Myall Lakes, September 2009, R.B. McCormack. ACP 2403 berried female, 2 g, 14.1 mm OCL, Myall Lakes, September 2009, R.B. McCormack. ACP 2411, male, 2 g, 15.1 mm OCL, Budgewoi Lake, September 2009, R.B. McCormack. ACP 2422, berried female, 1.5 g, 13.68 mm OCL, Tuggerah Lake, September 2009, R.B. McCormack. ACP 2532, male, 13.53 mm OCL, Port Stephens, December 2009, R.B. McCormack. ACP 2925, mix x 2, Wamberal Lagoon, May 2010, R.B. McCormack. ACP 2926, male, 4 g, 15.57 mm OCL, Wamberal Lagoon, May 2010, R.B. McCormack. ACP 2928, male, 3 g, 14.35 mm OCL, Wamberal Lagoon, May 2010, R.B. McCormack. ACP 4059, male, 3.65 g, 17.67 mm OCL, Myall Lakes, July 2012, R.B. McCormack. ACP 4063, female, 2.37 g, 16.46 mm OCL, Myall Lakes, July 2012, R.B. McCormack. ACP 4072, male, 2.99 g, 16.13 mm OCL, Myall Lakes, July 2012, R.B. McCormack. ACP 4074, female, 2.84 g, 16.52 mm OCL, Myall Lakes, July 2012, R.B. McCormack. ACP 4079, male, 4.26 g, 17.7 mm OCL, Myall Lakes, July 2012, R.B. McCormack. ACP 4100, female, 1.21 g, 12.91 mm OCL, Myall Lakes, September 2012, R.B. McCormack. ACP 4101, male, 1.97 g, 14.48 mm OCL, Myall Lakes, September 2012, R.B. McCormack. ACP 4102, male, 2.56 g, 14.84 mm OCL, Myall Lakes, September 2012, R.B. McCormack. ACP 4109, male, 0.83 g, 10.81 mm OCL, Myall Lakes, September 2012, R.B. McCormack. ACP 4114, male, 0.61 g, 9.77 mm OCL, Myall Lakes, September 2012, R.B. McCormack. ACP 4116, female, 1.11 g, 12.10 mm OCL, Myall Lakes, September 2012, R.B. McCormack. ACP 4121, female, 1.94 g, 14.66 mm OCL, Myall Lakes, September 2012, R.B. McCormack. ACP 4130, male, 1.39 g, 12.24 mm OCL, Myall Lakes, September 2012, R.B. McCormack.

Comparative material examined.

ACP 899, Gramastacus insolitus , male, 10 mm OCL, Moora Moora, Grampians, Victoria. ACP 927, Engaeus laevis , male, 15.81 mm OCL, Thurra River, Croajingalong, Victoria. ACP 2884, Engaeus lyelli , male, 22.54 mm OCL, Eildon, Victoria.

Diagnosis.

Rostrum long, narrow, reaching midlength or end of 3rd antennal segment, with spine at apex. Rostral carinae conspicuously raised and sharp, extending well back onto carapace just inside postorbital carinae. Carapace laterally compressed, deep, narrow. Antennal flagellum twice OCL. Antennal squame very long reaching end of 3rd antennal segment or beyond, widest at midlength, usually half as wide as long. Antennal basipodite spine variable, small to very large and sharp; coxopodite antennal spine absent. Interantennal spine wide, margins smooth and raised, with blunt to sharp spine. Areola very broad, width 0.5-0.7 times length, narrowest at centre. Telson U-shaped, margins gently converging to caudolateral corners, each with small sharp spine. Uropod outer ramus with 2 medium marginal outer spines with tuft of setae between. First chelae smooth and distinctly elongated. Males with large genital papilla.

Description.

Size. Maximum OCL 21.32 mm, 7 gram. Maximum size animals extremely rare, mean weight of large adults 4-5 gram.

Rostrum. Long, narrow, reaching midlength or end of 3rd antennal segment, approximately 0.3 × OCL. Rostral apex variable, ranging from very small to a large sharp conical acumen spine; apex upturned at 45-60° angle. Rostral carinae conspicuously raised and sharp, extending well back onto carapace, reaching beyond anterior end of postorbital carina; intracarinate region flat or slightly recessed, setose along mesial base of carinae with tuft of setae at apex of rostrum, carinae terminating at base of acumen in blunt process to large sharp conical rostral marginal spine upturned at 30° angle. OCL/CL 0.78-0.86. RW/OCL 0.09-0.14. RL/OCL 0.25-0.39.

Cephalon. Postorbital carinae conspicuously raised and prominent, anteriorly extremely variable from blunt to large sharp conical spine. Carinal length similar to rostral length. Suborbital spine small to medium. Antennal squame long, reaching to end of 3rd antennal segment or beyond, lateral margin slightly convex terminating in long, sharp conical spine, inflated at midlength. Cephalic setation variable, from slight to medium with scattered long bristle setae, densest towards lateral cephalic edge. SqL/OCL 0.18-0.32.

Thorax. Cervical groove deeply impressed, U-shaped. Postcervical groove lightly impressed, well separated from cervical groove, with postcervical groove diverging laterally; postcervical groove not continuous, vaguely extending just past the inner side of branchiocardiac groove. Branchiocardiac groove merging gradually with postcervical groove, with a distinct, short, transverse groove at posterior end of branchiocardiac groove. Areola very broad, 0.5-0.7 wide as long, narrowest towards centre. Carapace laterally compressed, deep, narrow, depth 0.67 × OCL, width 0.55 OCL. ArL/OCL 0.29-0.39. ArW/OCL 0.19-0.25. CW/OCL 0.51-0.59. CD/OCL 0.65-0.73.

Abdomen. Smooth, unarmed, with scattered long bristle setae. Some morphological differences between sexes (see Sexes). TAL average 1.66 × OCL. TAL/OCL 1.5-1.87. AdW/OCL 0.48-0.61 (average 0.54). TL/OCL 2.51-3.13 (average 2.84).

Tailfan. Telson U-shaped with sides gently converging to caudolateral corners, each with 1 small sharp standard spine. Outer uropod with 2 small standard marginal outer spines with tuft of setae between, 1 medium spine on longitudinal median carina on suture, longitudinal carina extends beyond suture, suture straight, 5-11 extra dorsolateral spines (outer) and 5-9 extra dorsolateral spines (inner) stopping just past half way. Outer uropod extends well past inner uropod and inner uropod extends just past caudal margin of telson. Inner uropod with medium standard spine at caudolateral corner, small upturned spine at base of longitudinal median carina (two specimens with 2 spines on one side). Tailfan with medium scattered long bristle setae. Coxopodite of the outer uropod terminating in rounded edge to medium conical spine, coxopodite of inner uropod terminating in small to medium conical spine. TEL/OCL; females 0.41-0.47 (average 0.45), males 0.38-0.47 (average 0.42).

Thoracic sternal keel. Sternal keel commencing as raised ridge posterior of LP1, thin sharp and recessed between LP1 and LP2. Rising at LP2 with slight dip between LP2 and LP3 with a small crest at LP3 and continuing straight as raised sharp ridge to LP4. LP4 with distinctive huge oval pores posterolaterally. Bullar lobes absent.

Gastric mill. TAP count 2.5-3.5. TAA 0.5-1.5. Spread 1-2. Urocardic ridges 2.

Antennae. Basipodite antennal spine small to very large and sharp. Coxopodite antennal spine absent. Interantennal spine wide, smooth raised margins, with blunt to pointed apex. Antennal flagellum twice OCL reaching posteriorly to 5th or 6th abdominal somites.

Third maxilliped. Third maxilliped with large raised spiniform process at mesioventral corner of coxopodite; ischium with sparse covering of short to long setae on ventrolateral surface, with carinate lateral edge and tuberculate laterodistal corner; exopodite multiarticulate and very long, 1.33-2.08 as long as ischium.

First cheliped. Distinctively elongated, proportionally larger in mature males than in reproductive females. General increase in setation along propodal and dactylar cutting edges in populations from the north to the south.

Propodus. Lightly punctated with mesial propodal margin starting as small rolled ridge at carpal articulation, progressing to small rounded mesial propodal spines scattered in twin lines giving a shadow effect to dactylar articulation. Cluster of small protuberances, some approaching small spines at perpendicular groove behind dactylar articulation. Dorsal and ventral propodal palm surfaces smooth. Shallow ventromesial and ventrolateral groves extending from apex along finger. Small granulations on lateral propodal edge usually (only distal 2/3 towards apex) but not on propodal finger. Light to medium setation along cutting edge with 2 prominent teeth.

Males (mean): PropL/OCL (1.07) 0.82-1.35, PropW/PropL (0.37) 0.33-0.44, PropD/PropL (0.255) 0.22-0.28.

Females (mean): PropL/OCL (0.87) 0.7-1.06, PropW/PropL (0.375) 0.30-42, PropD/PropL (0.245) 0.19-0.29.

Dactylus. Smooth, lightly punctated, with line of medium to large granulations along mesial edge increasing in size from dactylar articulation to apex between shallow dorsomesial and dorsolateral groves extending back from apex, fading out at approximately 40% dactylar length. One prominent tooth on cutting edge. Light to medium setation along cutting edges, more extensive in southern specimens. DactL/PropL: males (0.475) 0.41-0.54, females (0.51) 0.45-0.57.

Carpus. Smooth, with line of 6-9 small spines in irregular row along mesial edge, terminating in large sharp spine at articulation. Cluster of small protuberances in irregular line along ventromesial surface, several rounded, spiniform at articulation. Larger lateral carpal spine at articulation with group of smaller rounded spines along articulation edge. Setation absent.

Merus. Medium sharp outer distolateral meral spine, prominent dorsal meral spine. Setation absent.

Coloration.

Colour varying with population. First chelipeds very dark, black to black-blue with bright blue highlights along propodal, carpal and meral lateral edges, light blue tint ventrally with articulations dull to bright red. Cephalon dark black-brown dorsally, lightening laterally, many with blue highlight on lateral surface. Thorax and abdomen light brown, green, tan or steel blue, usually with small, light cream or red speckles. Body clear to cream ventrally. Juveniles (Wallis Lake) light blue.

Sexes.

No intersexed individuals were recorded, all being clearly either male or female. The male genital papilla is large, being a distinguishing character ( Riek 1972) from other crayfish species in the region. They are opportunistic breeders, starting in early August being reliant on water availability in their ephemeral habitats, only breeding when flooded. Females mature at approximately 12 mm OCL and are very fecund for their size: ACP 2318, 12.3 mm OCL, September 2009, Myall Lakes, 44 eggs; ACP 2387, 13.08 mm OCL, September 2009, Myall Lakes, 29 eggs; ACP 2309, 15 mm OCL, August 2009, Lake Macquarie, 82 eggs; ACP 180, 15.93 mm OCL, August 2005, Myall Lakes, 79 eggs; ACP 2300, 16.74 mm OCL, August 2009, Lake Macquarie, 100 eggs; ACP 2307, 17.56 mm OCL, August 2009, Lake Macquarie, 143 eggs. Eggs are dark olive green colour (ACP 2318), to deep dark purple (ACP 2384). Berried females have previously been captured from water after rain events in August, September and October with approximately 30-150 eggs. Egg incubation is swift with a 6-8 week period between eggs laid and juveniles released. Females breeding in early September released juveniles in late October.

Gramastacus lacus shows sexual dimorphism. Reproductively active females typically have broader abdomens with an abdominal anterolateral flap on the pleuron of abdominal somite 2 and have a smaller/narrower major cheliped then males. Reproductively active females are recorded between 12 and 18 mm OCL, but more research is needed (berried females over 18 mm OCL have not yet been recorded).

Etymology.

The Latin epithetlacus alludes to the coastal lake catchments that provide suitable habitat. Common name; previously referred to as "the lake yabby" ( McCormack 2008), however, I recommend "the eastern swamp crayfish" as more appropriate, in parallel to the only other recognized Gramastacus species, Gramastacus insolitus , commonly known as "the western swamp crayfish" ( Action Statement 2004).