Memoirs of the Museum of Victoria 54(2): 439-445 (1994) 31 December 1994 https://doi.org/10.24199/j.mmv.1994.54.15 A NEW SPECIES OF THE FRESHWATER GENUS ERICHSON (: ) FROM NORTH-WESTERN TASMANIA

Pierre Horwitz

Edith Cowan University. Joondalup Drive, Joondalup, WA 6027, Australia

Abstract

Horwitz, P. 1994. A new species of the freshwater crayfish genus Engaeus Erichson (Deca- poda: Parastacidae) from north-western Tasmania. Memoirs of the Museum of Victoria 54 (2): 439-445.

A new species of freshwater crayfish, , is described from Burnie in north-western Tasmania. The species can be readily distinguished by using characters estab- lished in the most recent revision of the genus Engaeus, notably the nature of the chelae, form of rostrum and the antennal flagella. It is proposed that the new species has a restricted

geographical range (not unusual for species in this genus), and that it is found in and around the city of Burnie. Its absence from previous extensive collections, its absence from parts of Burnie. and the restricted nature of the distribution, together highlight the need for adequate protection of the species.

Introduction iorly upturned to produce a bold spine. Rostral carinae conspicuous, tuberculate along length The genus Engaeus contains 34 species, 12 (but occasionally inconspicuously so), otherwise endemic to Tasmania (Horwitz, 1990). This smooth, long, fading out well beyond posterior paper reports on another endemic species from of rostrum, widely separated and ending the Burnie region in north-western Tasmania. abruptly almost at anterior of rostrum, not The following description follows the format fusing with rostral rim; intracarinate region and uses the same abbreviations of Horwitz depressed and U-shaped (in transverse), deep (1990). and asetose (except for small single setae in row along the inner margin of each carina). Suborbi- Engaeus yabbimunna tal angle variable; postorbital ridges low and

Figure 1 blunt. Eyes relatively small but pigmented area not reduced on orbital peduncle; antennal fla- Material examined. Holotype. Burnie Park, from gella short, not extending beyond posterior edge burrow in seepage area in gully of Shorewell Creek of carapace; antennal scale moderately long and below Oldacre Falls (GR 80 1 5 068 55 1 ), P. Horwitz, 9 Dec 1992, Museum of Victoria NMV J34474 (male, usually extending to distal segment of antennal OCL25.7 mm.) peduncle, 0.3 as wide as long and with long Allotype. Type locality, NMV J34475, berried tapering sharp conical terminal spine and cari- female, OCL 24.0 mm. nate lateral edge. Antennules biflagellate with Victoria Museum Paratypes. Type locality. Queen inner flagellum 0.5-0.6 as long as outer. Inter- berried' female, OCL 23.2 mm; QVM:10:11235. antennal scale generally triangular but variable burrow in ferny gully in Reserve Park on Romaine on that theme, with median longitudinal ridge or Creek. Burnie (GR 8015 080 513), Tasmanian swelling. 3rd maxilliped with raised (tuberculate Museum and Art Gallery G3529, P. Horwitz, 10 Dec spined) mesioventral corner of coxopodite; 1992, male. OCL 25.0 mm. or ischium with broad, largely asetose ventrolateral Other specimens. Type locality. 1 male, 1 female and 2 juveniles; type locality. Bill Walker, Feb 1992, 1 surface, with carinate lateral edge and laterodis- female, one juvenile; Cooee Creek in Burnie (GR tal corner produced to short spine; exopodite 8015:056520), from burrow in bank. 10 Dec 1992, P. either absent or shaft-like and less than 0.2 as (as for paratype). 1 Horwitz. 1 male: Romaine Creek long as ischium. male. 1 female. Carapace vaulted; areola 0.3-0.4 as wide as Description. Rostrum length variable but usually long. Carapace granulate on branchiostegal, extending to junction of penultimate and distal mandibular, antennal and orbital regions. Cer- segments of antennular peduncle, broad, anter- vical groove deepest at meson, V-shaped.

439 440 PIERRE HORWITZ

10mm

Figure I All diagrams arc of the holotype. A, . dorsal view of carapace; B, dorsal view of abdominal somites and elements oi the tail fan (telson and the inner and outer ramus of one uropod); C, lateral profile of sternum (from right sideol specimen); D, ventral view of sternum; E, lateral view of anterior cephalon; F, dorsal view of right antenna! scale; Ci. ventral view of third maxillipcd (from left side of specimen) showing coxopodite basipodite ischium and cxopodite; H, lateral view of carpus, propodus and dactyl of left chela; I, dorsal view of carpus propodus and dactyl ol left chela. A NEW SPECIES OF ENGAEUS FROM TASMANIA 441

TAL 1.08-1.17 X OCL. API reduced in (approximately 1.5 X as long as rostral length) fading width and with narrow pleura not overlapped by out posteriorly beyond level of posterior edge of orbit: forward extension of pleura of AP2. intracarinate region broadly U-shaped (in transverse), slightly deeper and minutely setose along Telson broad and well rounded caudally; each becoming inner margin of carinae. Suborbital angle obtuse, caudolateral corner with either a conspicuous approximately 110°; postorbital region moderately spine, a small spine or a notch only; outer ramus deeply depressed dorsoposteriorly; postorbital ridges of uropod with prominent longitudinal median short, bluntly raised; notch in orbital rim absent. Eyes carina, terminating in median spine on suture; small but pigmented area not reduced on orbital ped- suture straight, with 1-4 extra dorsomesial uncle; eyes extending halfway along rostrum. Antennal spines and with 0-4 extra (usually smaller) dor- flagellum short, extending to posterior edge of cara- scale moderately short, solateral spines; caudolateral corner with 0, 1 or pace, 1.08 X OCL; antennal extending to just beyond junction of penultimate and 2 spines on edge. Inner ramus with or without 1 distal segments of antennal peduncle. 0.08 X OCL, spine at caudolateral corner, with longitudinal 0.30 X as wide as long and widest at proximal two- median carina which fades out premarginally. fifths with conical, terminal spine occupying one-fifth Chelae isomorphic, largely non-granulate and of scale length, with distinctly cannate and straight asetosc. Propodal palm with single row of ventrolateral edge to spine, and long plumose setae rounded tubercles along dorsal edge, non-granu- along mesial edge. Antcnnules biflagellate with inner late and asetose laterally and mesially, and with llagellum 0.53 X as long as outer and outer 0.28 X tuberculate carina along ventral edge. Dactyl OCL. Interantennal scale broad with diverging lateral dorsally granulate or non-granulate. Carpus edges to rounded lateral corners before converging to centroventrally inflated. 3rd maxilliped smooth dorsally and laterally, without centro- rounded lip; with mesioventral corner of coxopoditc raised and dorsal depression and with row or band of small ridge-like, with one large and one smaller apical tubercles along dorsomesial edge. Merus with tubercles; ischium with long bristle setae and short plu- small tubercles along dorsal row or band of mose setae along ventromesial surface (becoming edge. sparse mesially and distally), with punctate, granulate Sternal keel commencing between LP 1st P and very sparsely setose, broad ventrolateral surface rising to low peak and then continuing as low but with cannate lateral edge (carinae with minute thin ridge, fading at articulations of 2nd P before tubercles along length) and spiniform laterodistal cor- reduced to a short stump (0.07 X as rising to low ridge, continuing to slight saddle ner; exopodite long as ischium). and rising again to fade out at 3rd P articulation Vaulted, 0.85 X as wide as deep; areola level, then recommencing as broad, low ridge Carapace. narrow, 0.35 X as wide as long (grooves faint). Bran- and terminating at articulation level of 4th P. LP chiostegites (particularly anteroventrally), mandibu- 1st and 2nd P without pores, otherwise con- lar, antennal and orbital regions of carapace granulate: spicuously raised; LP 3rd P each with pore open- areola and dorsal cephalon sparsely, minutely punc- at articulations and ing posterolaterally. peaked tate; dorsolateral cephalon glabrous. Cervical groove with much higher than keel summit; LP 4th P deep at meson and broadly V-shaped. rim, open- long slit like pores (beneath posterior Abdomen. TAL 1 .09 X OCL. AP 1 reduced in width, ing posterolaterally) and separated by deep Y- 0.51 X CTW and with unilobed pleura (lobe small and shaped valley. Bullar lobes with processes swollen), not distinctly overlapped by forward exten- and pleura of AP2-6 sloping anteromesially, separated by deep, sharp sion of pleura of AP2. Terga minutely punctate and largely asetose. groove and bluntly pointed posteriorly. Telson with tapering lateral sides to cau- Individuals either with male or female gono- Tail tan. dolateral corners (each produced to small spine) and pores only (no intersexed specimens found). Gill dorsal surface minutely punctate pleurobranch rounded caudal tip; formula usually 2 1 + ep (posterior and setose, with shallow depressions laterally and with fleshy stump). reduced to a short longitudinal, central groove caudally: caudal edge with long plumose and short bristle setae. Outer ramus of llololvpc Male uropod with short, fine bristle setae along lateral edge, Cephalon. Rostrum moderately long and broad. with low, longitudinal median carina terminating on extending to middle of distal segment of'antennular with or 4 with straight lateral transverse suture in median spine: suture 3 peduncle. 0.1 1 X OCL, spineless, spines dorsomesially and 4 extra smaller spines edges converging to upturned, bluntly pointed tip, extra dorsolateral^; suture itself moderately straight and whole rostrum curved downwards in lateral profile, deeply impressed along length; caudolateral corner bordered entirely by thin rim and dorsolateral!)" with 2 widely separated spines on one ramus and none extremely steep and concave between rim and carinae. on the other: caudal section of ramus with central Rostral carinae conspicuous, straight, converging with longitudinal groove fading out before caudal tip, anteriorly to end very abruptly but neither fusing otherwise with indistinct, minute carinae radiating themselves nor with the rostral rim, widely separated, long from suture caudally. with short bristle setae and tuberculate over at least anterior half, and 442 PIERRE IIOKWII/

longer plumose setae, along caudal edge; outer ramus level of 4th I'; LP 3rd P very high (higher than keel constricted a1 caudolateral and eaudomesial corners. summit) distinctly peaked al articulations, each with Inner ramus of uropod minutely granulate and setose pore opening posterolateral^, separated from keel on on dorsolateral hall', wilh prominent median carina either side by narrow channel. 4th P; keel as described extending almost entire length of ramus terminating above; LP peaked al articulations, ridged caudally, without spine: ramus dorsocaudally minutely striate; with large slit-like pore beneath posterior rim of each caudolateral corner without spine at edge; caudal edge process opening posterolateral^, and sloping inward wilh long plumose and short bristle:setae; ramus some- towards Sharp Y-shaped valley. Bullar lobes: large, cal- what leal-shaped in outline. Inner ramus of uropod cified and almost as long as broad, sloping antcrome- extending to beyond lelson caudally, outer ramus mar- sially to sharp, longitudinal groove in anterior half; ginally beyond that. Uropodal peduncle with both pointed posteriorly. lobes rounded and asetosc. .SV\. Without female gonopores; penes calcified

( 'hclac. Isomorphic, elongate and largely asetosc around perimeter. and non-granulate: DACL/PROPL, 0.59; PROPW/PROPL, 0.43; PRQPD/PROPL, 0.25; lllotype Female exhibiting secondary sexual PROPL/OCL, 0.99. Left chela: propodal palm with Specimen characteris- tics of reproductively active female (see Horwitz only very sparse pu notations laterally and mesially:

1 9X8). with 28 orange eggs, 2.0 1 .5 in dorsal edge with 15 tubercles in row along entire edge; and X mm diam- eter). for llolotype perpendicular groove indistinct; ventral surface eari- As Male except: nalc (with row of tubercles along carina proximally). ( I'phaloii. Rostrum 0. 1 1 X OCL, extending tojunc- lion Propodal linger with row of punelalions laterally of distal and penultimate segments of anlennal defining the continuation of the carina (from ventral peduncle. Anlennal llagcllum 1.00 X OCL; anlennal surface of propodal palm), otherwise smooth; cutting scale 0.09 X OCL. 0.34 X as wide as long, occupying approximately one-sixth of scale length. Inner antcn- edge with I large compound tooth in proximal corner nular llagcllum 0.58 as long as outer().32 followed by 8 small teeth along edge to tip. Dactyl X outer with X smooth but with 3 longitudinal rows of punctations OCL. 3rd maxilliped with raised mesioventral cor- ner of (dorsal, dorsomesial and dorsolateral) and with one coxopodite (wilh 2 apical tubercles); ischium row of sparsely separated small tubercles dorsome- with carina but not granulate along length; e.xopodite

0. 1 2 x as long as ischium. sially; cutting edge with 13 teeth decreasing in size over proximal two-thirds of edge, followed by scale ( arapace. 0.85 X as wide as deep; areola 0.36 X as w ide as long. setae to tip. Carpus with very shallow centrodorsal groove, with tuherculalc ventral projection and Mhlomeu. TAL 1.16 X OCL. sparsely punctate laterally and dorsally. with row of I ail Fan. Telson with lateral edges straight and par- allel to tubercles along lateral edge, row of tubercles along dor- caudolateral corner; one caudolateral corner produced to somesial edge (clustered proximally) and extra, small a small spine, the other spineless. Outer tubercles along ventral area of mesial triangle; other- ramus wilh 3 or 4 extra dorsomesial spines along suture wise smooth. Merus will) glabrous mesial surface; with and 2 or 3 extra spines dorsolateral^; outer glabrous lateral surface sparsely granulate dorsally; ramus wilh only one spine on caudolateral corner (of both rami). Inner dorsal surface with prominent dorsal spine amongst a ramus ovoid, with spine at caudola- double row of spiniform tubercles along edge; ventral teral coiner; uropodal peduncle with a tuft of small surface granulate centrally, and with tubercles con- setae. ( hclac. tinuous along mesial and lateral rows. Left chela small, elongate and presumed Right Right chela slightly smaller than left; as for left chela regenerating. chela elongate and largely asetosc: except: 16 luberclcs in row along dorsal edge of pro- DACL/PROPL. 0.54; PROPW/PROPL. 0.45; PROPD/PROPL, 0.27; PROPL/OCL. 0.93; as for iso- podus. I small tooth followed by I compound tooth and 8 small teeth a long cut ting edge of propodal linger, morph of Holotype Male except: 13 tubercles along dorsal and dactyl with 12 teeth along cutting edge. edge of the propodus; cutting edge of propodal linger with 4 teeth in proximal third followed by Sternum. 1st I': keel present as low rounded ridge at small scale setae along edge to tip; cutting edge of dactyl with postei 101 of I I', rising immediately to small peak then 2 teeth proximally as ridge continuing to 2nd P; LI' poslerovenlrally followed by small scale setae to tip. setose, conspicuously raised but without pores, separ- Propodal linger with tufts of small setae arising from ated by narrow, moderately deep channel (becoming punctations (which are arranged in rows). Sex, broader and Fading oul at posterior level of processes). Without male gonopores but wilh huge, open female gonopores (ovoid, 1.3 0.7 2nd I': keel fading oul between articulations, then X mm diameter). rising to thin crest between LP and beyond, slightly Morphological variation. The species displays lower than LP at articulations, before decreasing in some considerable morphological variation and height to saddle between 2nd and 3rd P; LI' posterov- some may be attributable to enlrally setose, distinctly raised, without pores, and geographical location. The mesioventral corner of the separated from keel on either side by narrow , shallow coxo- is channel 3rd I': keel rising to low peak before fading podite tuberculate on individuals from Burnie out completely at articulation level, then rising to low Park. Shorewell Creek, but at both Romaine and broad rulge before dropping steeply at articulation Cooee creeks it is bluntly spined. The interan- A NEW SPECIES OF ENCABUS FROM TASMANIA 443

tcnnal spine from Romaine and Cooee creeks is another parastacid, Astaeopsis gouUli Clark. No clearly triangular and pointed, but at Shorcwcll microhabitat separation has been discerned Creek it is bluntly rounded with either convex or between the Engaeus species. concave lateral edges. The exopoditc of the third E. yabbimunna occupies burrows in the flood maxillipcd is absent on individuals from beds of creeks dominated by tree ferns, in Romaine Creek and extremely short on those burrows next to creeks, in seepages dominated from Cooee Creek; Shorcwcll Creek individuals by tea tree and with a ground cover of ferns, and generally have a short shaft-like stump up to 0.2 well above creeks in burrows on the creek bank times as long as the ischium. or slopes of the gully. Soils in these habitats The suborbital angle ranges from about 80° to ranged from brown to orange-red clay loams, or about 130°; the ventrolateral surface of the contained a high level of organic matter. Veg- ischium can be tuberculatc or lumpy not smooth etation was typical of wet gullies, with Aeaeia (see Holotype). The individual from Cooee melano.xylon dominant in the over-story. Creek had a spincd rostrum which was not Burrow structure depended on the type of habi- upturned. tat and depth to water table and seemed typical of other members of this genus. Relationship to other speeies. When applied to So far the species has not been found from the key to species in the genus EngaeUS given in habitats where native vegetation no longer exists Horwitz (1990). E. yabbimunna terminates at (see below). couplet 28 with E. tayatea Horwitz. It can be distinguished from this species by the nature of Distribution and conservation. Previous searches the chela; whilst those of E. tayatea have for burrowing freshwater crayfish in Tasmania tuberculatc propodal palms with tufts of bristle have been extensive and detailed (see Horwitz, setae. E. yabbimunna has a smooth and asetose 1990; Richardson, unpublished data), and have propodal palm. It is readily distinguished from revealed for northern Tasmania some well E. fossor (Erichson) by the presence of only one defined distributions. E. fossor for instance has a row of tubercles on the dorsal surface of the pro- broad range across northern and western Tas- podus (instead of two rows as in E. fossor), by the mania, as do E. eistemarius and E. lengana form of the rostrum and rostral carina, and by (Horwitz, 1990). The fact that E. yabbimunna the shorter antennal flagella. Its phylogenetic has until now escaped detection is evidence that affinities are unclear in spite of sharing several some species are found locally and not over a morphological similarities with the four species broad area. in couplets 27 and 28 (E. fossor, E. strielifrons Collation of all data on the distribution of bur- Smith Schus- (Clark), E. tayatea and E. fultoni & rowing freshwater crayfish within about 10 km in the western Bassian ter, three of these occur of Burnie has produced a distribution map (Fig. region with E. yabbimunna). 2). Within the Burnie area itself eight sites were Etymology. The specific epithet was rec- investigated. Many burrows of E. yabbimunna ommended by members of the Northwest Coast were found at the Shorewell Creek and Romaine Aboriginal Language Programme in Burnic and Creek sites where flood bed and seepage areas means "little claw". were relatively undisturbed. Only one burrow was found at the Cooee Creek site where the Life history notes. LM. 25.7 mm OCL; LRF. 26.0 creek was receiving sediment from its western SRF. 23.2 OCL; LNRF, 1 5.6 mm mm OCL; mm side (industrial activity) and used by cattle on its Berried females were collected in early OCL. eastern side. Further down Cooee Creek the

1 992; no females carrying larvae were December original vegetation has been replaced by willows had just been found, suggesting that eggs and no burrows were found. Other parts of in the early phases of extruded and/or were Shorewell Creek were searched to no avail, predominance of berried developing. In fact a including an area downstream of the old dump, was found at sites then (of eight adults females and in the upper reaches adjacent to a sports the type locality, six were berried found at oval; at both localities riparian vegetation had were returned to females). Most berried females been completely removed. Parts of Shorewell popu- their burrows to avoid depleting the Creek and Romaine Creek which have been lation. landscaped (where vegetation has been removed channelized, for instance) were Ecology, The species has been found sympatri- and the creek burrows. These data suggest cally with E. fossor (at the type locality) and is similarly devoid of likelv to occur in the same creek systems as that: 444 PIERRE HORWITZ

Figure 2. Distribution of Engaeus yabbimunna (closed circles) around Burnie (with urban area stippled) in northern Tasmania, showing the main water courses in the region, known localities of other species (E. fossor asterisk, E. disjuncticus closed triangle), and locations where searching revealed no burrows of freshwater cray- fish (open circles).

i) E. yabbimunna may have a restricted dis- hundred kilometres apart, has recently been tribution in the Burnie area and may be confined found in the Burnie area (Richardson, pers. to the three creek systems from which it has been comm.; Fig. 2). found; and Even given this possibility, E. yabbimunna ii) populations of E. yabbimunna may have should be regarded as neither widespread nor been eliminated by human activities in parts of common. Accordingly, and given that threaten- the Burnie area. ing processes can be identified, the species The restricted distribution hypothesis is sup- should be considered threatened and steps ported by the presence of E. only fossor at should be taken to consolidate knowledge on its localities surrounding the three creeks, and the ecology and manage its known populations failure to find E. yabbimunna elsewhere during appropriately. extensive surveys for Engaeus (see above). Alternatively, there is always the (albeit remote) Acknowledgements chance that the species will occur elsewhere in northern Tasmania. For instance, the enigmatic Bill Walker (Burnie City Council) found the E. disjuncticus, so named in Horwitz (1990) species and referred specimens to Alastair because of its disjunct populations over one Richardson (Zoology Department, University A NEW SPECIES OF ENGAEVS FROM TASMANIA 445

of Tasmania); I thank both of them for their con- females of the freshwater crayfish genus Engaeus 27- tinued interest in the species. Jacqueline Court- (Decapoda: Parastacidae). Crustaceana 54: enay inked the drawings and compiled the 32. Horwitz, P. ( 1 990). A taxonomic revision of species in distribution map. the freshwater crayfish genus Engaeus Erichson (Decapoda: Parastacidae). Invertebrate Tax- References onomy 4: 427-614.

Horwitz, P. ( 1 988). Secondary sexual characteristics of