Lynceus macleayanus (King, 1855)

TIMMS, BRIAN V, 2013, A Revision of the Australian species of Lynceus Müller, 1776 (Crustacea: Branchiopoda: Laevicaudata, Lynceidae), Zootaxa 3702 (6), pp. 501-533 : 503-508

Lynceus macleayanus (King, 1855) .

( Figs. 1 , 2 , 3C , 4A )

Limnetis macleayana King, 1855: 70 ; King, 1864: 162–164., pl 11, fig. without number; Brady 1886: 83 (list); Whitelegge

1889: 318 (list); Sars 1895: 35–43, pl.6,7; Henry 1924: 121–122 (list), 135 (text). Lynceus macleayana .— Sayce 1903: 258–259, pl. 36, fig D, 1,2,3; Dakin 1914: 295 (list); Chilton 1917: 481. Lynceus macleayanus . — Wolf 1911: 255 (list); Daday 1927: 6 (key), 53–57, fig. 157; Martin & Belk, 1988: 452 (list); Brtek,

1997: 60 (list); Richter & Timms 2005: 342–343.

Comments. King’s (1855) original description and its addition (King 1864) do little to define the species, though there is no doubt it belongs to the genus Lynceus . Fortunately Sars (1895) described and figured the species adequately, though lacking detail of the male first thoracopod. His material was from Hay, NSW, 590 km west from the type locality, the Botany swamps in Sydney. Neither author left any material and King’s type locality has long since been destroyed. Choosing a collection and locality to establish a neotype is difficult. The collection from Dulwich Hill in Sydney (AM P8420 & P88143) and only a few kms from the original type locality, is unsuitable as it contains only juveniles and also the site no longer exists. Although the species has been collected in the mountains north and south of Sydney (AM P47130, P47133), and in the Clarence Valley (AM P55687, P88082, P88083, P89072) 540 km to the north, the collection from Hay was chosen for designation of a neotype. This is because Sars (1895) used material collected from this site and some of it exists in the Australian Museum (as AM P16180) (presumedly the two collections are part of an original larger collection by the same Mr A.M. Lea). This choice helps to ensure the neotype is a valid representative of Lynceus macleayanus . The fact that it comes from well inland rather than from a coastal swamp (like the Botany swamps) is a secondary consideration in that L. macleayanus is a widespread species, coastal and inland, southern and northern (see later).

New type locality: Hay, inland NSW, no date for collection, but late 1800s, collector A.M. Lea.

Neotype: Male deposited in the Australian Museum (Sydney). Length 6.3 mm. Registration number AM P90062 (whole animal) & P90062.1 (thoracopod 1)

Other Material. New South Wales: 126 km NW of Bourke, pool on Tredega Station , 29 o 27’ 44”S, 144 o 51’08”E, 11 September 1989, BVT, AM P89070 ; 86 km N of Bourke, Lake Ballymere on Ballycastle Station , 30 o 06’ 21”S, 145 o 02’ 36”E, 31 May 1990, BVT, AM P89071 ; Harwood Island, Lower Clarence River , Jan 1963, A.A. Cameron, AM P55687 & P88158 ; Taloumbi , 7 April 2001; NSW Fisheries Coastal Floodplain Project; AM P80872, P80873, P88377, P88378 ; 22 km SE of Maclean, Brooms Head , pool on headland, 29 o 36’ 48’S, 153 o 20’ 19”E, 11 March 2008, BVT, AM P89072 ; Barrington Tops, 5.8 km SE of Polblue Rest Area , 31 o 59’ 25”S, 151 o 28’ 22”E; 22 February 1995, BVT, AM P47133 & P88148 ; Sydney, Dulwich Hill , no date, A. Royce, AM P8420 & P88142 ; Hay , no date, A.M. Lea, AM P16180 & P88145 ; 6 km SSE of Narooma, pond near L. Nargal , 36 o 16’ 01”S, 150 o 08’ 41”E, 25 September 2006, BVT, AM P89073 ; 49 km NE of Menindee, Surbinton Waterhole , 32 o 05’ 16”S, 142 o 46’39”E, 19 October 1988, BVT, AM P89074 .

Northern Territory: Darwin, Knuckeys Lagoon, pool at end of Fiddlers Lane , 12 o 25’ 45.6”S, 130 o 56’ 44.6”E, 21 Feb 2006, S Richter, AM P90483 ; Kakadu, Waterlily Billabong , 4 January 2005, MZ ,; Barkly Tableland, Alexandria Station, Ranken Creek , 20 o 31’S, 137 o 35’E, 16 December 1981, M.J. Tyler and M. Davis, SAM C7630 .

Queensland: Tully , 26 January 1961; IAEB, AM P55658 & P88155 ; 28 km NNW of Stonehenge, Lochern National Park , burrow pit, 24 o 06’ 05.0”S, 143 o 14’ 48.6”E, 10 January 2010, A. J. & F. M. Emmot, AM P89065 ; 52 km N of Taroom, near Palm Tree Creek , unnamed lagoon, 25 o 12’54.2”S, 149 o 34’ 34.5”E, 13 February 2010, BVT & MS, AM P89066 ; 6.5 km SE of Meandarra , gilgai (=waterhole), 27 o 21’ 25”S, 149 o 55’ 28”E, 7 July 2009, BVT, AM P89067 ; Wyandra , 1920, E. L. Fletcher, AM P15751 & P88144 ; 102 km SW of Cunnamulla, Rockwell Station, Number 10 Creek , 28 o 47’ 46”S, 145 o 03’ 10”E, 9 June 2007, BVT, AM P89068 ; 121 km SW of Cunnamulla, Rockwell Station , pool on western boundary, 28 o 55’ 45”S, 144 o 55’ 33”E, 9 June 2007, BVT, AM P89069 ; 16 km N of Hungerford, Currawinya National Park, 10 Mile Waterhole ; 28 o 51’ 49”S, 144 o 27’ 56”E, 16 May 1996, BVT, AM P47951 & P88379 .

South Australia: Mungala near Keith , claypan, 31 October 1971, P. Gneil, SAM C7629 .

Tasmania: Flinders Island, temporary wetland on margin of ‘ Wingaroo ,’ 39 o 52’S, 147 o 58’E, 8 November 2011, J. Gooderham, AM P89075 ; 6.4 km S of Perth near Launceston , 20 March 1964, J. Wilson, AM P 55653 & P88150 ; Cleveland, Smiths Lagoon , 24 November 1963, J. Wilson, AM P55655 & P88152 ; 6.4 km N of Campbell Town , 24 December 1963, J. Wilson, AM P55654, P55662, P88151, P88156 ; Campbell Town, 23 October , 1910, no collector recorded, NMV J54007 , J62977 , J62977.1 ; Richmond, Football Oval , ‘pond of death,’ 42 o 43’ 44”S, 147 o 26’ 13”E, 25 April 2011, J. Gooderham, AM P89076 .

Victoria: Ouyen , October 1915, J.E. Dixon, NMV J54032 , J62976 , J62976.1 ; Fairfield , 19 November 1910, no collector recorded, NMV J 53993 , J62978 , J62978.1 ; Elwood , 18 Jul 1899, Cummins, NMV J54030 , J62985 , J62985.1 ; Sandford Marsh , 20 October 1969, no collector recorded, NMV J54002 , J62979 , J62979.1 ; Southern Victoria, no date or collector recorded, NMV J46626 , J62986 , J62986.1 .

Western Australia: Meekatharra, Annean Station , 1911, no date recorded, A. Snell, WAM 51319 ; 14.5 km NW of Eneabba, Arro Well Swamp , 29 o 43’ 33”S, 115 o 09’ 39”E, 17 September 2009, BVT, WAM 51584 ; 13 km E of Jurien , swamp near road, 30 o 15’ 46”S, 115 o 10’ 26”E, 16 September 2009, BVT, WAM 51585 ; 5 km by road N of Moora , roadside swamp, 30 o 33’ 54”S, 116 o 09’ 57”E, 6 September 2009, BVT, WAM 51586 ; 6 km SW of Cateby Roadhouse, Brand Highway, roadside pool on Mimegarra Rd , 30 o 46’ 06”S, 115 o 29’ 11”E, 17 September 2009, BVT, WAM 51587 ; 20 km by road E of Corrigan , 10 September 1982, M. Geddes, WAM 51588 ; 85 km E of Hyden, L. Cronin , 32 o 23’ 05”S, 119 o 45’ 55”E, 16 October 2008; BVT, WAM 51589 ; 12 km S of Salmon Gums, roadside pool on Esperance-Norseman Rd , 33 o 04’ 56”S, 121 o 41’ 13”E, 25 January 2007, BVT, WAM 51590 ; Grass Patch, Swan Lagoon , 33 o 16’S, 121 o 38’E, 17 October 1886, GFL, WAM 51328 ; 32 km W of Israelite Bay , 5 December 1959, D. H. Edwards, AM P55659 ; Nullarbor Plain, between Loongara and Forrest along railway line, 3 August 1966, J. Lowry, WAM 51329 .

Diagnosis. Thoracopod I of male with endite VI arcuate with basal portion attached to endite III wider than length of the digitiform process as measured at its base, but the two subequal at their junction. This digitiform process triangular tapering to a sharpish apex, flanged underneath and reaching about one quarter the medial margin of Endite III.

Description of Neotype. Male. Head (Fig. 1,2B,C): subequal to body size, finely punctuate. Fornices broad, angulated and arcuate over second antennal base, and dividing the head into upper and lower parts. Site of dorsal organ on a small mound centroposteriorly. Compound eyes close together about midway along the central ridge between the cervical suture and rostrum. A small frontal pore and two small lateral setal fields just anterior to the eyes, and an ocellus deeply embedded beneath the setal fields. Rostral dorsal surface lower than surface posterior to compound eye, the junction marked by the lateral suture from the eye to the nearby fornix. Rostrum slightly longer than wide, with apex truncated and about 50% wider than at its narrowest middle section. Dorsal carina sharp and bifurcated horizontally at right angles to from a terminal triangular facet vertically.Apical margin gently arcuate and ciliated.

First antenna ( Fig 2B ) small, almost reaching to rostrum apex. Two antennomeres, both cylindrical and subequal in length. Distal antennomere bearing numerous olfactory papillae mainly dorsally. Each papilla with a delicate digital process.

Second antenna ( Fig 2C ) biramous, well developed, protruding beyond the rostrum by about half its length. Peduncle of three segments, proximal one with two to three plumose setae, middle segment with one to two spines and the distal peduncular segment with about eight short spines anteriorly laying against the first antennomere of anterior ramus. Anterior ramus with about 25 antennomeres and ventral ramus with a few more antennomeres, about 28. Both rami with long plumose ventral setae, one per antennomere, while anterior ramus with short dorsal setae also.

Labrum large, linguiform, clothed in small setae particularly apically.Mandible broadly spatulate. First maxilla typical for genus and second maxilla absent.

Carapace ( Fig 2A ) with hinge line slightly arcuate, umbo and growth lines lacking. Anterior margin broadly convex, curving evenly to ventral margin and back to the convex posterior, though posterior slightly narrower than anterior curvature, so deepest part of carapace a little before midway along its length. Hinge line slightly hidden in arcuate groove between the valves of the carapace. Valves roundly inflated laterally. Carapace surface finely punctuate. Abductor muscle scar in an anteriolateral position about twice its diameter from the margin and associated with oval imprint of maxillary glands lying at about 20 o to the hinge line.

Thorax: Ten thoracic segments each with a pair of thoracopods. The telsonic posterior plate partly divided centroposteriorly, each half bearing a long setae apically ( Fig 2D ). Somite below enlarged, similarly divided and bearing small denticle apically.

Thoracopod I modified as a clasping appendage, right and left claspers equal in size and shape ( Fig 1 , 3C ). Endite VI arcuate with basal portion attached to endite III wider than length of digitiform process at its base, but the two basal portion of endite VI and the digitiform process subequal at their junction. This digitiform process triangular tapering to subacute apex, flanged underneath (i.e. on surface opposed to Endite III) and reaching only about one quater the medial length of endite III. Endite V cylindrical, curved and about three times longer than wide. A vertical row of about 15 stout setae extending from near one-third from the endite base to its apex and an oval field of dishevelled thinner setae centered about half the diameter of the endite from the vertical row at its base but extending almost to be adjacent to the row apically. Endite IV about one third the length of endite V, asymmetrical with margin adjacent to endite V almost straight and with a few short setae and the opposite margin convex and with many long setae. Endite III rectangular but narrowing distomedially. Six rectangular spines in a row at distomedial corner and a field of stout long setae on a lateromedial field, with these setae clumped distally, and shorter and more spaced on inner edge of plane than on margin coincident with medial edge of endite III. Anterior setae on endite II similar to posterior setae, but half their size. Some anterior setae serrated on each side on terminal half.

Thoracopod II of typical form (Martin and Belk 1988, Ferrari and Grygier 2012, details for L. baylyi n. sp. below), but no serrated setae on endites II and III.

Thoracopods III to VII similar to previous ones, though decreasing in size posteriorly.

Thoracopods VIII to X pairs very reduced and lacking the epipodite and proximal lobe of the exopodite.

Comments on female. The female of L. macleayanus ( Fig. 2E–J ) is much as described and figured by Sars (1895).The head is similar to the male’s but without the terminal truncation. Sars (1895) shows an almost rectangular rostrum with straight sides and straight apical margin, but most often the sides are gently arcuate, the apical margin more intensely arcuate and sometimes there is a notch on the anteriolateral corner ( Fig. 2F ). Both antennae, the carapace and thoracopods II to XII are as in the male and described by Sars (1895). The lamina abdominalis (= a conjoint lamellar lateral process of last few trunk segments) has a digital process anteriorly and two digital processes laterally as well as a more broadly triangular process posteriorly. In addition there is a narrow digitiform process dorsoanteriorly. The shape of the first three processes is variable between localities, so that they can be triangular or even lobate.

Resting egg: ( Fig 4A ) Round, irregular low wide ridges enclosing enlongated irregular depressions. Size 118.6 ± 3.1 ųm (n = 5).

Size: Neotype length 6.3 mm, height 5.3 mm, width 2.8 mm.

Variability: The male rostrum varies in relative width between localities, giving a known range of 30–50% increase over the narrowest section mid length. Thoracopod I can have up to nine spines on endite III rather than the six of the neotype and six to seven in Sars’ specimens. While the digitiform process of endite VI can be more triangular than in the neotype, usually it is more tumid than the more strictly triangular digitiform process of L. magdaleanae . The strong spinal row on endite V can have as few as 12 spines instead of the usual 15–16. Spinal length and density also vary on the mediolateral setal field of endite III, and serrated anterior setae on endite II are often absent. The number of antennomeres on the anterior ramus of the second antenna varies little around 25 (24– 26), the number varies more on the ventral ramus (26–31), and the number of setae on the basal peduncle antennomere ranges between 2 and 6 .

Distribution. Lynceus macleayanus occurs almost Australia wide, though uncommon in the north and there are not many records from South Australia, Victoria and most of Western Australia. It is most common in NSW and southern Qld and also coastal in Western Australia between Perth and Geraldton. It never occurs in gnammas and records by Bayly et al. 2012, Timms 2006, 2012 and Zofkova 2006 under this name are erroneous and should be changed to L. magdaleanae sp.nov.

Figures

FIGURE 1. Exemplar drawing of labelled male head and thoracopod I of L. macleayanus. Scale bars 1 mm.

FIGURE 2. L. macleayanus, A–D male: A, carapace; B, first antenna; C, second antenna; D, anal plate and somite. E–J female: E, carapace; F dorsal view of head; G, lateral view of head; H, anal plate and last somite; K, lamina abdominalis. Scale bars 1 mm.

FIGURE 3. Digital Images of claspers of Lynceus. A, L. tatei (from Serpentine, WA, WAM 51609); B, L. tatei (from Armadale WA, MZ Collection); C, L. macleayanus (from Brooms Head, NSW, AM P89072); D, L. baylyi sp.nov. (from Washington Rocks, WA, WAM 51581); E.L. magdaleanae sp.nov. (from Yanneymooning Rock, WA, WAM 51604); F, L. susanneae sp. nov. (from Cocklebiddy, WA, WAM C51326)

FIGURE 4. Resting eggs of Lynceus. A. L. macleayanus; B, L. tatei; C, L. argillaphilus sp. nov.; D, L. baylyi sp. nov.; E, L. magdaleanae sp. nov.; F, L. susanneae sp. nov. Scale bars 50 ųm.