Limnadopsis tatei Spencer & Hall, 1896

Timms, Brian V., 2009, A Revision of the Australian Endemic Clam Shrimp Genus Limnadopsis Spencer & Hall (Crustacea: Branchiopoda: Spinicaudata: Limnadiidae), Records of the Australian Museum 61 (1), pp. 49-72 : 55-58

Limnadopsis tatei Spencer & Hall, 1896

Figs. 2B , 4B , 5D,E , 6 , 7

Limnadopsis tatei Spencer & Hall, 1896: 241 , figs. 20–27; Sayce, 1903: 250; Wolf, 1911: 254 (list); Dakin, 1914: 295 (list); Henry, 1924: 122 (list), 132 (key); Richter & Timms, 2005: 349.

Limnadiopsis tatei .— Daday, 1925: 181–183, fig. 123 (misspelling of the genus name).

Limnadiopsium tatei .— Novojilov, 1958: 104, fig. 12; Brtek, 1997: 58 (list).

Types. Originally no types designated. Now a neotype (3) has been chosen ( NMV J54053 ) .

Comments on types. The neotype is thought to be from Professor Spencer’s original collection from Central Australia. Certainly its characteristics agree with the limited original description.The exact location of the type locality is unknown and even the date is not in museum records, but it is believed to be 1896. Given that this species is widespread and variable (see later), it is helpful to have a neotype taken from the type locality, illdefined as it is.

Material. New South Wales: 93, 16♀, NW of Bourke, Bloodwood Station, Shining Box Pool , 29°27'S 144°50'E, 24.v.2000, B. V . Timms , AM P76803 ; 6 specimens, 140 km NW of Bourke, Tredega Station, Johnsons Tank , 29°30'S 144°54'E, 26.i.1995, B. V . Timms , AM P47127 . Queensland: 33, 1♀, E of Thargomindah, Bindegolly National Park, Lake Hutchinson , 1.ii.2006; 27°55'S 144°13'E, M. Handley; QM W28369 ; 13, E of Thargomindah, Bindegolly National Park, Lake Toomaroo , 17.i.2007; 27°59'S 144°12'E, M. Handley; QM W28370 ; 13, E of Thargomindah, Bindegolly National Park, Lake Bindegolly , 9.ii.2007; 28°04'S 144°12'E, M. Handley; QM W28371 ; 18 individuals, SW of Cunnamulla, Rockwell Station , grassy pool S of North Blue Lake, 28°51'S 144°58'E, 9.vi.2007, B. V . Timms , QM W28372 ; 69 individuals, near Hungerford, Currawinya National Park, the Yapunyah Swamp , 25°30'S 144°18'E, 18.v.1996, B. V . Timms , AM P47948 ; 5♀, near Hungerford, Currawinya National Park, Killambirdie Waterhole , 25°48'S 144° 30'E, 8.v.1996; B. V . Timms , AM P55618 . Central Australia: 23, no details, Prof Spencer, NMV J54043 ; 13, Onkaparinga Ck , no details, Prof Spencer, NMV J54053 . SouthAustralia : 33 , 1♀, Olympic Dam , 30°28'S 136°44'E, 12.ii.1981, M.J. Tyler, SAM C6347 ; 1♀, Olympic Dam , 44 km east, 30°28'S 136°45'E, 12.ii.1987, M.J. Tyler, SAM C6348 ; 33, 3♀, Olympic Dam, 8 km on track to Lake Blanche , a samphire swamp, 30°29'S 136°48'E, M.J. Tyler, SAM C6349 ; 23, Roxby Downs , 30°42'S 136°46'E, M.C. Geddes, SAM C6350 ; 33, 96km N of Port Augusta, M. Wickstein , ii.1962, SAM C6354 . WesternAustralia: Gascoyne District, Landor Station , pool near homestead, no date or collector, WAM C3485 ; 11 km S of Wittenoon, pools at head of Joffie Falls , 22°23'S 118°16'E, 12.vi.1970, M. Shepherd, WAM C39331 ; near Yalgoo , 5.x.26, J. Clark, NMV J43991 ; 103, 10♀, W of Cue, Austin Downs Station , swamp near homestead, 31.viii.2004, 27°23'S 117°45'E, B. V . Timms , WAM C39332 ; c. 35 individuals, near Laverton , roadside swamp 20 km west, 28°36'S 122°13'E, 22–1–2007, B. V . Timms , WAM C39333 .

Distribution. Australia-wide, mainly in the central and northern inland. It is not recorded from southern NSW, Victoria, Tasmania, southern SA, or southern WA.

Description of neotype. Carapace ( Fig. 6A ) 12 mm by 7.6 mm, L:D ratio c. 1.6. Dorsal margin weakly curved convexly, with anterior portion depressed at umbo and slightly upturned towards dorsoanterior corner. Ten robust growth lines. Carapace dorsal surface with each growth line extended as carina. Carinae posterior to umbo large and asymmetrical and directed posteriorly, but those anterior to umbo the carinae minor and constituting small, anteriorly-facing steps in the dorsal line. Each carinae wholly contained within a single growth zone. Umbo area slightly widened anterolaterally. Carapace surface texture granular.

Head ( Fig. 6B ) with pyriform frontal organ situated posteriorly, preceded by a rounded ocular tubercle, and rostrum orientated at right angle to head. Rostrum length about 1.5 times its basal width; apex rounded and slightly bent posteriorly and base containing triangular naupliar eye dipping obliquely with respect to rostrum axis and occupying much of its basal area.

First antenna a little longer than second antenna peduncle, with 10 subequal lobes. Second antenna with two flagellae, each composed of about 15 beaded flagellomeres, these of variable length but generally longer and thicker proximally. Most of middle flagellomeres with 5–7 spines laterally, with no apical grouping.

Trunk segments 26. Posteriormost segment with spineless dorsal protuberance, preceding 7 segments each with 1–3 spines its protuberance; next more anterior 6 segments with long setae varying in number from many posteriorly to 1–2 on more anterior segments ( Fig. 6C ). Hand of claspers ( Fig. 6D ) with asymmetrical outgrowth on anterior edge of basal half. Immovable finger with numerous spines apically: central ones short and stout, but these changing to long, thin curved spines on inner edge. Palp of movable finger short with hair setae apically. Base of movable finger broad, supporting posteriorly an evenly curved finger terminating in a small spine. Palp two-segmented, as long as hand in the first clasper and about half as long again in second clasper. Distal segment bearing many short hair setae apically. No setae on junction of two palp segments.

Third thoracopod ( Fig. 4B ) similar in structure to that of L. birchii ( Fig. 4A ). Proportions of endites, endopod, exopod and epipodite slightly different, and significantly palp of the fifth endite only about half its length. Other thoracopods of same basic structure, but without palp and generally epipodite larger.

Telson ( Fig. 6C ) armed with 11 spines in each row, spaced unevenly and of various widths and lengths.Anterior spine about three times as large as the others and curving slightly posteriorly; posterior spine with posteriormost 3 telsonic spines on its anterior surface, curved anteriorly and more than twice as long as wide at the base. Two telsonic setae inserted on protuberance about one third of way along dorsal margin of telson. Caudal claws well developed, more than twice as large as posterior telsonic spine and unevenly curved concavely forward. Basal half thick, almost straight, and bearing about 10 shortish hair setae mesodorsally. Short spine about two-thirds of way along the claw on dorsal surface, followed by row of many denticles dorsally on pointed apex of claw.

There are no females in the original collection by Prof.

Spencer, so no description of a female L. tatei is available.

Variability. As noted by Spencer & Hall (1896), the carapace of males varies in the shape of its dorsal outline from straight, as in the Austin Downs specimens ( Fig. 7A ) to slightly convex as in the neotype ( Fig. 6A ). Further variability is seen in size of adult male carapaces (9–13 mm long), the number of growth lines (7–11), and the development of the dorsal spines. The latter range from being almost absent, as in the specimens from Yalgoo, to well developed as in most specimens seen. The male rostrum ( Fig. 7B ) is often relatively longer than in the neotype, reaching twice its basal width and the degree of rounding and posterior bending very variable. First antennal lobules usually range from 8–10 and antennal segments from 12–16; both were often observed to be damaged and missing parts. Most specimens have 26 body segments, but a few have only 25. Major variability in the telson ( Figs. 6C , 7C,H ) includes the number of dorsal spines, ranging from 9–13, caudal claw setae varying from 8–12, and spines varying from 1–3, more often three than the one of the neotype. The anteriormost dorsal spine is always at least twice the size of other such spines, and often even larger, as in the neotype.

Females are similar to males ( Fig. 7F–H ), as was first noted by Spencer & Hall (1896). They noted that the dorsal margin of the carapace is distinctly more convex in the female, the rostrum is shorter, and there are fewer lobules in the antennule than in the male. In the present material, the rostrum is as long as deep and there are about 6–8 lobules in the first antenna while the flagellomeres of the second antenna usually numbering 12–15; both figures are a little less than those of males. Number of body segments, posterodorsal armature, and the telson are similar to those in males.

Eggs. Eggs are different in the eastern and western populations studied ( Fig. 3D,E ). In both they are round and about 150 µm in diameter (range 144–171 µm, n = 10), and the surface has numerous straight furrows not as wide or deep as in L. birchii . In the western population the intervening ridges are sharper and the furrows tend to be short and arranged in short, nested Vs of 2–3 furrows, while in the eastern population, the ridges are frilly, longer and more randomly arranged. The significance of these different egg sculpturings is unknown; the eggs could be variable as in L. parvispinus (see later), or the differences could indicate separate species in the east and west. The later possibility is not supported by any consistent differences in the morphology of the adults.

Comment. Novojilov (1958) transferred Limnodopsis tatei into a new genus Limnadiopsium which has not been followed here (see later).

Figures

Fig. 2. Photographs of whole specimens of species of Limnadopsis. (A) L. birchii; (B) L. tatei; (C) L. parvispinus; (D) L. minuta; (E) L. multilineata; (F) L. occidentalis; (G) L. paradoxa; (H) L. pilbarensis. Scale bars 5 mm.

Fig. 4. Third thoracopods of males of (A) L. birchii; (B) L. tatei; (C) L. parvispinus; and (D) L. paradoxa n.sp. A few of the numerous setae (see text), and details of the major types of setae are shown only for L. birchii. Scale bars 1 mm.

Fig. 5. SEMs of eggs. (A) Limnadopsis birchii, Twin Pans, Currawinya National Park, Qld; (B) L. birchii, Bluebush Bore Swamp, via Carnarvon, WA; (C) L. multilineata, Mitchell River Falls, Kimberley, WA; (D) L. tatei, Bloodwood Station, Paroo; (E) L. tatei, near Laverton, WA; (F) L. pilbarensis, Chichester Range, WA; (G) L. parvispinus, Bloodwood Station, via Bourke, NSW; (H) L. parvispinus, Coolringdon Station, via Cooma, NSW; (J) L. occidentalis, Boolathana Station, via Carnarvon, WA; (K) L. paradoxa, Sieda Farm, Grass Patch, WA; (L) L. paradoxa, East Lake Bryde, via Newdegate, WA; (M) L. minuta, Keep River National Park, NT. Scale bars 50 µm.

Fig. 6. Limnadopsis tatei Spencer & Hall, lectotype, central Australia. Male: (A) carapace; (B) head; (C) telson and dorsoposterior surface of trunk; (D) second clasper. Scale bars 1 mm.

Fig. 7. Limnadopsis tatei Spencer & Hall, Austin Downs, via Cue, WA. Male: (A) carapace; (B) head and antenna 1; (C) telson; (D) second clasper with some details. Female: (E) carapace; (F) head and antenna 1; (G) telson. Scale bars 1 mm.

Fig. 3. Limnadopsis birchii (Baird), Bloodwood Station, via Bourke, NSW. Male: (A) carapace; (B) head; (C) telson; (D) antennule; (E) a middle flagellomere of second antenna; (F) second clasper. Female: (G) head. For clarity some growth lines of the carapace are incompletely shown anterior to umbo. Scale bars 1 mm.