Austronecta carinata ( Chen, 1965 ) Tinerella, 2013

Tinerella, Paul P., 2013, <strong> Taxonomic revision and systematics of continental Australian pygmy water boatmen (Hemiptera: Heteroptera: Corixoidea: Micronectidae) </ strong>, Zootaxa 3623 (1), pp. 1-121 : 24-29

Austronecta carinata ( Chen, 1965) , comb. nov.

( Figs. 12–15 )

Micronecta carinata Chen, 1965: 157 .

Micronecta carinata: Wróblewski, 1972b: 524 . [list]

Micronecta carinata: Cassis and Gross, 1995: 67 . [catalog]

Micronecta carinata: Andersen and Weir, 2004: 250 , 334. [key; list]

Diagnosis: Austronecta carinata is easily recognized by the pronounced anterior pronotal carina, distinctly salebrose dorsum, and linear dark patterning of the hemelytra ( Figs. 12b–d ). Male left paramere distinct ( Figs. 15a–e ) and females distinguished by combination of characters given below.

Size: ( Table 5). Brachypterous form: 2.58–2.75. Macropterous form unknown.

Derivation of specific epithet: From the Latin carinata , meaning keel, referring to the pronounced carinate anterior margin of the pronotum.

Notes on type material: Chen (1965: 157) listed depositing the holotype and allotype in MCZC. As of this writing, I have been unable to locate the type specimens through MCZC. I received correspondence from MCZC stating that these specimens may have been transferred to ANSP during a large exchange of material between the two museums. Sources at ANSP were unable to locate the holotype. Further investigation is needed. I have examined Chen’s paratype (♀) ( Figs. 12a–b ), which is deposited in SEMC.

Description: Based on brachypterous form. Measurements. Length: male 2.59–2.75; female 2.58–2.67; Width: male 1.44–1.52; female 1.42–1.51; Width of head: male 0.92–0.96; female 0.91–1.00; Synthlipsis: male 0.38–0.40; female 0.37–0.40; Width of eye: male 0.30–0.32; female 0.26–0.32; Width of pronotum: male 0.91–0.93; female 0.89–0.93; Length of pronotum: male 0.23–0.25; female 0.24–0.26.

Color: Ground color light brown ( Figs. 12b–d ). Head brown, eyes dark reddish-brown. Vertex yellowishbrown, a single darker, longitudinal line from top of head to vertex. Frons and clypeus dark brown, labium dark black. Clypeogenal area same color as frons, uniformly punctate. Antennae yellowish-brown. Pronotum pale yellow apically with pale yellow band spanning width, medial and lateral portions dark brown. Hemelytra: clavus with irregular darker blotches, both basally and distally. Corium with four irregular discontinuous longitudinal stripes. Dense transverse microsculpturing prominent over clavus and medial portion of corium. Scutellum short, unicolorous dark brown. Prenodal embolar area short, widened, lacking distinct pruinosity. Nodal furrow hardly distiguishable, very short. Post-nodal area wide, very short. Two restricted, discontinuous, infuscated areas along each embolium, the apical infuscation being wider ( Figs. 12c–d ). Membrane subhyaline, dark brown, unicolorous. Venter dark brown, distal portion of middle and hind legs, natatorial setae, and metatarsal claws darkened.

Structural characteristics: Ratio of body length/width: males 1.81; females 1.78. Head slightly wider than pronotum, interocular space slightly larger than width of eye, synthlipsis 1.3 times as wide as posterior width of eye. Ocular index: males 1.41; females 1.35. General facies of head (vertex, frons, and labium) very short. Antennae densely pilose, segments one and two very short, third segment long, elongated, ovate, with lower margin broadly rounded, apex acuminate. Pronotum very short, anterior margin triangular with sharp, well-produced carina. Posterior margin truncate, medial portion widest with lateral margins very narrow, tapering. Pronotum averaging six times as wide as long (W/L: males 1.47/0.24; females 1.47/0.25). Prothoracic lobe short and broad ( Fig. 13a ), anterior and posterior margins rounded, lower margin nearly straight. Hemelytra with dense transverse microsculpturing throughout, setae densely and uniformly distributed. Surface of pronotum and hemelytra rugulose and pitted. Lateral spines on abdominal segments IV–VIII: IV: two thin, long setae; V: two stout, short setae, one long, stout seta, one long, thin seta; VI: two stout, short setae, one long, stout spine, one long, thin seta; VII: two short, stout spines; VIII: three stout, short spines, one short, thin seta. Metaxyphus of both sexes very short, broadly triangular, apex rounded ( Figs. 13b , 14a ).

Male foreleg ( Fig. 13c ): femur with two short, stout spines in basal third near ventral surface. Tibia with one short spine in apical portion, near ventral surface. Pala with five long setae dorsally; palmar area with 14–15 setae in upper row, 16–17 setae in lower row, ventral row setae more pronounced than dorsal row. Apex of pala lacking a short, thickened seta. Palar claw ( Figs. 13d , 14b–c ) narrow, elongated, and strap-like. Female foreleg with same general setal arrangement as male. Mesotarsal claws short, equaling about one-third the length of the mesotarsus.

Lateral lobes of abdominal tergum IV comparatively narrow, rounded apically. Right lobe slightly broader and longer, with 11–12 long setae, left lobe shorter, with 12 long evenly spaced, apically placed setae. Prestrigilar flap of tergal segment V as in Figure 13e . Strigil very small, disk-like, with few combs. Median lobe of sternite VII ( Figs. 13f , 14d ) short, broad, with two longer setae restricted sub-basally, apex pointed. Free lobe of tergite VIII ( Fig. 13g ) broad, nearly quadrate with inner angle rounded. Inner angle with 19–23 short setae, of more or less uniform length. Pars stridens processus cleaner ridges of tergite VIII not examined. Male left paramere ( Figs. 15a–e ) short, shaft somewhat parallel-sided, apical portion curved with narrow, pointed tip ( Figs. 15a–d ). Paramere base broad, upper portion of base extending to middle portion of shaft. Lower portion of base broadly curved ( Figs. 15a–e ). Right paramere ( Figs. 15a–e ) long, curved inward, constricted at base, tip of paramere tapering to a point ( Figs. 15a–e ). Base of right paramere long, lower portion rounded, with about 42 plectral ribs spanning width ( Fig. 15f ). Aedeagus broad, as in Figures 15a–d .

Distribution and Habitat: AUSTRALIA: New South Wales. Primarily a lotic species, as seen from AMSA survey data (see below). Locally abundant across New South Wales, particularly in the eastern portion of the state.

Discussion: Austronecta carinata is a distinct species, likely to be confused only with the smaller sympatric A. australiensis . Smaller individuals of A. carinata appear similar, however, the dorsum of A. carinata is always pronouncedly salebrose and the hemelytral patterning always contrasting. Some degree of variability in hemelytral patterning is seen with A. carinata (amorphous dark areas vs. dark linear corial patterning), and very dark forms of both species have been noted.

The species is clearly allied with other Austronecta on the basis of the anterior pronotal carina and similar abdominal morphology. The genitalia of A. carinata are similar to A. australiensis , however, the left paramere of A. carinata is shorter and truncate apically.

Specimens examined: AUSTRALIA: New South Wales: Point Lookout National Park, Serpentine River . 13-VIII-1961. D. J. Woodland. (16♂, 24♀♀). [ USNM] ; New South Wales: d/s Bimberamala River . 35 25 59S; 150 11 36E. 11-X-1994. Edge. Eren Turak. (1♀). [ AMSA] ; New South Wales: Buckenbowra River . 35 38 18S; 149 59 14E. 13-X-1994. Edge. Eren Turak. (2♂, 2♀♀). [ AMSA] ; New South Wales: Myanba Creek . 36 57 02S; 149 28 43E. 16-X-1994. Edge. Eren Turak. (1♀). [ AMSA] ; New South Wales: Towamba River, Coolangubra. 36 53 48S; 149 27 36E. 16-X-1994. Edge. Eren Turak. (1♀). [ AMSA] ; New South Wales: Minnamurra River u/s Museum. 34 38 18S; 150 43 11E. 1-XII-1994. Edge. Eren Turak. (1♀). [ AMSA] ; New South Wales: Jingo Creek . 36 59 31S; 149 39 35E. 16-III-1995. Edge. Joanne Ling. (2♀♀). [ AMSA] ; New South Wales: Wog Wog River, Nalbaugh. 37 01 53S; 149 26 29E. 16-III-1995. Edge. Eren Turak. (1♂). [ AMSA] ; New South Wales: Abercrombie River, Speary Ridge. 34 10 12S; 149 56 08E. 23-III- 1995. Macrophytes. Frances Laurenson. (1♂). [ AMSA] ; New South Wales: Upper Hastings River at Werrikimbe. 31 11 29S; 152 12 57E. 8-IV-1995. Edge. Eren Turak. (1♂). [ AMSA] ; New South Wales: Manning River, Gummi Trail. 31 51 27S; 151 34 11E. 9-IV-1995. Edge. Joanne Ling. (8♂, 14♀♀). [ AMSA] ; New South Wales: Manning River, Gummi Trail. 31 51 27S; 151 34 11E. 9-IV-1995. Riffle. Joanne Ling. (17♂, 25♀♀). [ AMSA] ; New South Wales: Urumbilum River . 28 44 48S; 152 56 42E. 11-V-1995. Edge. Joanne Ling. (5♂). [ AMSA] ; New South Wales: Brogers Creek . 34 42 02S; 150 41 11E. 2-VI-1995. Riffle. Frances Laurenson. (1♂, 2♀♀). [ AMSA] ; New South Wales: Brogers Creek . 34 42 02S; 150 41 11E. 2-VI-1995. Riffle. Joanne Ling. (2♀♀). [ AMSA] ; New South Wales: Chichester River near Hut. 32 09 34S; 151 34 33E. 4-X-1995. Edge. Eren Turak. (1♂). [ AMSA] ; New South Wales: Manning River, Ninnes Trail. 31 49 12S; 151 38 36E. 4-X-1995. Edge. Frances Laurenson. (1♂, 2♀♀). [ AMSA] ; New South Wales: Upper Hastings River at Werrikimbe. 31 11 29S; 152 12 57E. 4-X-1995. Edge. Alexander Leask. (3♂, 1♀). [ AMSA] ; New South Wales: Hastings River, the Crest. 31 27 57S; 152 36 11E. 5-X-1995. Edge. Eren Turak. (1♀). [ AMSA] ; New South Wales: Manning River, Gummi Trail. 31 51 27S; 151 34 11E. 5-X-1995. Edge. Joanne Ling. (5♂, 9♀♀). [ AMSA] ; New South Wales: Tobins River u/s Mount Seaview Lodge. 31 23 59S; 152 14 34E. 6-X-1995. Edge. Eren Turak. (7♂, 3♀♀). [ AMSA] ; New South Wales: Little Dandahra Creek, Mulligans Hut. 29 31 02S; 152 21 33E. 9-X-1995. Edge. Joanne Ling. (1♀). [ AMSA] ; New South Wales: Urumbilum River . 28 44 48S; 152 56 42E. 12-X-1995. Edge. Eren Turak. (3♂, 1♀). [ AMSA] ; New South Wales: Bimberamala River . 35 26 43S; 150 03 54E. 24-X-1995. Edge. Russell Cowell. (1♂). [ AMSA] ; New South Wales: d/s Bimberamala River . 35 25 59S; 150 11 36E. 25-X-1995. Edge. Alexander Leask. (1♂, 2♀♀). [ AMSA] ; New South Wales: Murrah River, Knights Creek . 36 32 50S; 149 58 50E. 25-X-1995. Edge. Eren Turak. (4♂). [ AMSA] ; New South Wales: Chalkhills Creek . 36 54 18S; 149 47 41E. 27-X-1995. Edge. Natacha Waddell. (1♀). [ AMSA] ; New South Wales: Tuena Creek d/s Bear’s Gully. 34 04 28S; 149 22 08E. 14-XI-1995. Edge. Russell Cowell. (4♂). [ AMSA] ; New South Wales: Grabben Gullen Creek u/s Lachlan River . 34 32 25S; 149 09 27E. 15-XI-1995. Macrophytes. Russell Cowell. (1♀). [ AMSA] ; New South Wales: Yadboro River u/s Budawang National Park . 35 18 54S; 150 08 19E. 21-XI-1995. Eren Turak. (1♂). [ AMSA] ; New South Wales: Lyons Creek . 35 34 12S; 150 04 41E. 23-XI-1995. Edge. Eren Turak. (1♂). [ AMSA] ; New South Wales: Kangaroo River up Gerrigong Creek . 34 41 17S; 150 35 58E. 4-XII-1995. Edge. Joanne Ling. (1♂, 3♀♀). [ AMSA] ; New South Wales: Jocks Creek u/s Cox’s River . 33 34 18S; 150 04 38E. 8-XII-1995. Edge. Natacha Waddell. (10♂, 17♀♀). [ AMSA] ; New South Wales: Brogers Creek . 43 42 02S; 150 41 11E. 12-XII-1995. Riffle. Alexander Leask. (1♂). [ AMSA] ; New South Wales: Lyons Creek . 35 34 12S; 150 04 41E. 4-III-1996. Macrophytes. Marie Eggerup. (1♀). [ AMSA] ; New South Wales: Mataganah Creek . 36 52 45S; 149 38 53E. 5-III-1996. Edge. Joanne Ling. (1♀). [ AMSA] ; New South Wales: Wog Wog River, Nalbaugh. 37 01 53S; 149 26 29E. 8-III-1996. Edge. Marie Eggerup. (2♂, 2♀♀). [ AMSA] ; New South Wales: Brogers Creek . 43 42 02S; 150 41 11E. 17-V-1996. Riffle. Joanne Ling. (1♀). [ AMSA] ; New South Wales: EPA Survey MRHI, Roseberry Creek, Rich 505. 28 28 29S; 152 49 24E. 9-V-1997. Edge. Alexander Leask. (5♂, 2♀♀). [ AMSA] ; New South Wales: Kangaroo River up Gerrigong Creek , SHOA 01. 34 41 17S; 150 35 58E. 10-VI-1997. Edge. Alexander Leask. (4♂, 1♀). [ AMSA] ; New South Wales: Kangaroo River up Gerrigong Creek , SHOA 01. 34 41 17S; 150 35 58E. 26-XI-1997. Edge. J. Potts. (10♂, 4♀♀). [ AMSA] ; New South Wales: Kangaroo River up Gerrigong Creek . 34 41 17S; 150 35 58E. 30-IV-1998. Edge. T. Rankin. (2♂). [ AMSA] ; New South Wales: Shoalhaven River, Fossicher’s Flat , SHOA 05. 34 49 16S; 150 11 32E. 10-XII-1998. Edge. Eren Turak. (1♂). [ AMSA] ; New South Wales: Kangaroo River u/s Gerrigong Creek , SHOA 01. 34 41 17S; 150 35 58E. 13-XI-1998. Edge. Natacha Waddell. (2♂). [ AMSA] .

Figures

FIGURE 12. Austronecta carinata (Chen), paratype and dorsal habitus. a. Locality and type labels. b. Paratype specimen, female, dorsal habitus. c. Male. d. Female. Scale bars = 0.5 mm.

FIGURE 13. Austronecta carinata (Chen). a. Prothoracic lobe, female. b. Metaxyphus. c. Left male foreleg, posterior aspect. d. Left male pala (tarsus), anterior aspect, palar claw everted. e. Prestrigilar flap of abdominal segment V. f. Sternal process of abdominal segment VII. g. Free lobe of abdominal tergum VIII. Scale bars = 0.1 mm.

FIGURE 14. Austronecta carinata (Chen). a. Metaxyphus. b. Left male pala (tarsus), anterior aspect, palar claw everted. c. Left male pala, ventral aspect. d. Sternal process of abdominal sternite VII.

FIGURE 15. Austronecta carinata (Chen). a. Left paramere, lateral aspect, right paramere, dorso-frontal aspect. b. Left paramere, medio-lateral aspect, right paramere, dorsal aspect. c. Left paramere, lateral aspect, right paramere, medio-lateral aspect. d. Left paramere, medio-lateral aspect (cf base Figs. a,b,c,e), right paramere, lateral aspect. e. Left parameres, base, right paramere, dorso-medial aspect. f. Pars stridens processus, base of right paramere.