Gabbia campicola, Ponder, 2003

Ponder, Winston F., 2003, Monograph of the Australian Bithyniidae (Caenogastropoda: Rissooidea), Zootaxa 230 (1), pp. 1-126 : 31-37

Gabbia campicola n. sp.

Etymology Campus ­ Latin ­ field, plain. cola ­ Latin ­ dweller, inhabitant.

Type material 5.5 km S of turnoff to Thornwood HS, NE of Nyngan, NW of Warren on road to Carinda, NSW, 31° 3.500'S, 147° 29.100'E, amongst sedges and macrophytes, 16 SEP 1996, W.F.Ponder & A.Kornuishin (Holotype AMS C.417664, paratypes AMS C.332829, 110 wet, 5 dry 3 on SEM stubs; QM 71719, 5; NTM P21380, 4) .

Additional material examined

Queensland: Red Falls, on Lolworth R 19° 56.000'S, 145° 44.000'E, basalt wall, AUG 1981, F.S.Colliver ( QM MO13176 , 6 ) ; on road between Nebo & Mackay, 21° 23.550'S, 148° 56.330'E, in mud on edges of swamp, 12 SEP 2000, W.F.& J.M.Ponder ( AMS C.386131, 1) ; 20 km S of Funnel Ck, S of Sarina , 21° 35.000'S, 149° 12.000'E, brigalow scrub, mud under leaves in deep depressions, 28 MAY 1977, I.Loch, P.Colman & R. Creese ( AMS C.307898, 20+) ; Nebo, Ca. 30 km SW at Mt Flora Stn , 21° 53.083'S, 148° 35.417'E, Eucalypt woodland/brigalow ­ on ground, 23 JUL 1994, J.Stanisic, D.Potter, G.Ingram & C.Eddie ( QM MO54307 , 7 ) ; Dipperu NP, S of Nebo, 21° 56.000'S, 148° 42.000'E, SEP 1971, Baldwin ( QM MO26515 , 1 ) ; Western R, 0.2 km S of Winton, 22° 23.000'S, 143° 2.000'E, on weeds in channels, AUG 1983, G.Knight ( QM MO57226 , 2 ; QM MO57223, 4) ; 0.2 km S of Winton on Jundah Rd , 22° 23.550'S, 143° 2.460'E, mud along edge of bore drain, 20 JUN 1996, W.F.Ponder & D.L. Beechey ( AMS C.327895, 8) ; SW of Barcaldine, 7 km E of Landsborough Hwy, rd to Rosemont , 23° 49.500'S, 145° 22.000'E, in bore fed ck at roadside, 27 SEP 1984, W.F.Ponder & P.H.Colman ( AMS C.308009, 13) ; Cluny , 24° 32.000'S, 139° 37.000'E, from flood plain, 25 AUG 1978, B. R. Jahnke ( QM MO57227 , 5 ) ; Retreat Stn , 25° 12.000'S, 143° 16.000'E, temporary water in paddock, 30 MAR 1982, B.J.Smith ( MV F 54869 , 19 ) ; between Cunnamulla and Charleville , 28° 1.130'S, 145° 44.930'E, in mud in water, 17 JUN 1996, W.F.Ponder & D.L.Beechey ( AMS C.318702, 20+; AMS C.351062, 2; AMS C.347629, 2) ; W of Eulo on S side of road, 28° 8.750'S, 144° 57.000'E, 04 SEP 1984, W.F.Ponder & P.H. Colman ( AMS C.307893, 25) ; spring at Tunga Bore near Mt Tunga ca 43 km WSW of Eulo, 28° 13.000'S, 144° 38.000'E, in boulder strewn creek, 06 SEP 1984, W.F.Ponder & P.H.Colman ( AMS C.308010, 20+) ; Binya Stn , 70 miles S of Cunnamulla, 29° 4.000'S, 145° 41.000'E, in ditch from bore, 05 DEC 1980, C. Roper ( AMS C.307882, 15) ; Bore no.1, Binya bore drain, Binya Sheep Stn , 29° 4.000'S, 145° 41.000'E, 05 DEC 1980, C. Roper ( USNM 803665 , many; C.344345) ; 3.5 miles N of bore no. 1, Binya Sheep Stn , 29° 4.000'S, 145° 41.000'E, 07 DEC 1980, C. Roper ( USNM 803667 , 5 ) .

New South Wales: Moppin­Aveymore Rd, ca. 400m S of junctn at Dolgelly Bore, 28° 53.433'S, 149° 51.500'E, 29 NOV 1999, L.Wilkie, R. Harris & T.Moulds ( AMS C.417764, 1); Boxflat near Brindingabba Ck N. of Bindra Stn, NW of Bourke, 29° 2.611'S, 144° 49.571'E, 20 MAY 1994, P.H.Colman & J.Kelly ( AMS C.303294, 2); NW of Bourke, Bloodwood Stn , via Yantabulla, 29° 32.000'S, 144° 55.000'E, pool ( AMS C.203379, 20+); Bloodwood Stn, Bells Ck, lower Crescent Pool , 29° 33.000'S, 144° 52.000'E, 01 MAR 1998, B.Timms ( AMS C.346352, 20+); Bullaroon Stn., off Mitchell H'way N. of Bourke , 29° 40.632'S, 146° 9.476'E, black soil floodplain, 19 MAY 1995, P.H.Colman & J.Kelly ( AMS C.305358, 20+); Merah North, small pool in small stream gully on E side of village, 30° 12.000'S, 149° 18.000'E, on surface of mud amongst sedges etc., 17 SEP 1996, W.F.Ponder & A.Kornuishin ( AMS C.327926, 20+) .

Description (based on type material only, other than anatomy)

Shell ( Figs 2 G­K, 3F­I, 13A,B) moderately large (up to 8.3 mm in length), ovate­conic to conic, of up to about 5 convex whorls. Protoconch of about 1.5 smooth whorls. Teleoconch sculptured with fine collabral growth lines and extremely minute, irregular spirally orientated, short wrinkles (visible only with SEM); base evenly convex; umbilicus usually closed (represented by small chink), sometimes perforate and very small. Aperture broadly ovate; peristome weakly thickened on inner lip, outer lip slightly thickened within in adults, prosocline. Colour: shell opaque to transparent, periostracum thin, yellow­brown, edge of outer lip dark brown.

Dimensions. See Table 3 for dimensions of holotype and figured paratype and Appendix, Table 29 , for summary shell dimensions and whorl counts.

Operculum ( Fig. 4 G­I) typical of genus. Ovate, semitranslucent white, concentric growth ridges distinct; inner surface sculptured with small, closely­spaced pustules.

Radula (Appendix Table 30 ; Fig. 11 A­G; 16B,C) typical of genus. Central teeth with 4 (­5) cusps on either side of median cusp which is about equal in length to lightly longer than adjacent cusps and its base is about as wide to slightly wider; median cusp triangular to short finger­shaped. Face of central tooth with 3­4 pairs of cusps that extend just inside lateral margin forming short denticulate ridge, inner pair much larger than others, sharp, rather small (about 0.14 total height of tooth); lateral margins strongly concave, upper part at about 70­75º, lower part at about 50­55º; basal tongue long, narrow, bluntly pointed. Lateral teeth with cusp formula 3­4+1+4­5; with cutting edge about 0.36­0.40 length of lateral part of tooth; median cusp up to about twice as long as adjacent cusps, tapering and pointed; upper edge of lateral part of tooth at about 60­70º to cutting edge, lateral edge concave. Inner marginal teeth with 16­20 cusps, outer marginals with 9­12 cusps.

­ G. cf. rotunda .

Head­foot with snout and bases of tentacles usually weakly to strongly pigmented pale to dark grey; tentacles, if pigmented, grey with unpigmented edges and 1­2 narrow dark longitudinal lines or unpigmented with median grey line. Foot and opercular lobes unpigmented to grey. Mantle roof dark to pale grey, rarely unpigmented, mottled with white spots. Visceral coil sometimes black dorsally.

Anatomy. Gill with apices at or very near right edge except at anterior third where they are at fifth to third gill width from right; 50­75 filaments (n=5). Osphradium opposite middle of gill to slightly anterior to middle. Penis ( Fig. 7A, D ) with accessory lobe shorter than penial lobe to subequal, with distal swelling; accessory gland short to medium length. Pallial oviduct similar to G. vertiginosa but with very narrow (less than a quarter of height of capsule gland), latero­ventrally located bursa copulatrix (AMS C.332829, AMS C.327926, USNM 803665).

Distribution ( Fig. 9 ) and habitat. North western New South Wales and western Queensland south of 19º. A few lots from coastal Queensland in the vicinity of Mackay are also (somewhat tentatively) assigned to this species. Found in temporary swamps, pools and similar habitats on mud or clay.

Remarks

This species is found in western parts of northern NSW and in western Queensland. It is characterised by the shell being moderately large, rather thin­shelled with a straightsided spire and in having a mottled (black and white) roof to the mantle cavity.

This species is similar to G. iredalei but differs in radular characters. The central teeth of G. campicola have sharper cusps and a shorter pair of inner basal cusps (occupying less than 0.2 of the tooth height compared with about 0.5) and fewer (2­3 compared with 4­5) and relatively weaker subsidiary basal cusps, and the lateral edges are typically more strongly concave (although straight to weakly concave in USNM, 803665).

Bythinia vertiginosa is also very similar but differs from G. campicola in having a more globose shell and the central and lateral teeth of the radula usually have straight lateral margins. Never­the­less, specimens of the two taxa are often difficult to place using shell characters alone and there is an apparent gradation in shell characters between the two taxa on the western slopes of the Great Divide in the New England area but the radula characters clearly place this material in G. vertiginosa (see above). The penis in G. campicola has a shorter accessory gland than in G. vertiginosa , although it is rather variable in length ( Fig. 7A,D compared with 7I,J). In addition, G. campicola differs in having a much more weakly pigmented head­foot and, although the mantle roof is usually mottled, it is often not as darkly pigmented as in G. vertiginosa .

The description is based on the type material only owing to uncertainty of the allocation to this taxon of some of the material attributed to it. For example, a small lot from Retreat Station in western Queensland (MV F.54869) has more distinct spiral microsculpture but is otherwise similar (including the radula). Some specimens (typified by AMS C.318702) have some differences in the central teeth of the radula to the type material of G. campicola including: basal tongue more triangular and sharper; cutting edge more triangular and much more strongly concave on its dorsal margin; basal denticles stronger; and lateral edges only weakly convex to almost straight. They agree in having a pustulate inner side to their operculum. Their shells also lack any distinctive features that separate this material from typical G. campicola and they are here tentatively considered to represent the same species­group taxon. Similar radular features to those seen in AMS C.318702 are seen in specimens from Binya Stn and vicinity (AMS C.307882; USNM 803665, 803667), although the basal denticles are more similar to those in the typical material. In addition the median cusps of the central and lateral teeth are about twice as long as the cusps on either side. These have a mottled mantle and a similar shaped shell to G. campicola but it has distinct axial colour lines that are especially noticeable in juveniles, and traces of spiral sculpture are present. The above samples are otherwise not able to be readily differentiated morphologically from G. campicola and are here also treated as varieties of that taxon.

The two species appear to abut in their range west of the New England area (see Fig. 9 ). Further studies are needed to clarify the detail of the distribution of these taxa in this area and whether or not they are always allopatric.

Specimens from the Murray R drainage in the vicinity of Kerang, Victoria (10 km W of Kerang, VIC, 35° 44.000'S, 143° 52.000'E, standing water on side of road, 27 AUG 1976, B.J.Smith [MV F 54838 , 11]; Leaghur Forest, 20 km SW of Kerang, VIC, 35° 58.000'S, 143° 46.000'E, 24 MAY 1975, J.McVicar & J.Gilmore [MV F 78762 , 2]), have a similar shell that is somewhat intermediate between G. vertiginosa and G. campicola . A single empty shell, also from the Murray­Darling drainage, from the Gwydir R, below Moree (29° 25.000'S, 149° 50.000'E, 12 APR 1992 [Murray Darling F/W R.C.]), is also similar to the Kerang material and has traces of spiral sculpture. There is insufficient material to determine whether or not these specimens represent one or two distinct taxa and they are tentatively referred to as G. aff. vertiginosa .

A discriminant function analysis using the shell dimensions and the number of whorls of the measured samples ( Table 4 ; Figs 10B ) showed that 89% of G. iredalei and 83% of G. vertiginosa were correctly identified with only 35% of G. campicola specimens being incorrectly placed in both the other two species. When the forms from Victoria and eastern South Australia are included, the results are even less clear cut ( Table 5 ; Fig. 10C ). The difficulty in the assignment of G. campicola reflects the considerable variation in shell morphology in what is considered here to be a single taxon. Given this variation and the considerable geographic range, further analysis involving molecular data may possibly reveal greater taxonomic diversity than recognised here.

Figures

FIGURE 2. Shells: A – E, Gabbia vertiginosa, A, AMS, C.203392, B ­ D, AMS, C.308015, E, AMS, C.332890; F, Gabbia iredalei, AMS, C.337418; G – K, Gabbia campicola, G, AMS, C.344345, H, holotype, C.417664, I, paratype, C.332829, J, K, MV, F.54869; L­N, Gabbia kendricki, L, holotype, WAM S10877, M,N, paratypes, AMS C.203378; Scales: A – E, L­N, 500 m, F, 2 mm, G – K, 1mm.

FIGURE 4. Opercula: A ­ E, Gabbia vertiginosa, A, B, AMS, C.203392, C, D, AMS, C.308015, E, AMS, C.332890; F, Gabbia iredalei, MV F.54870; G ­ I, Gabbia campicola, paratype, AMS, C.332829; J ­ L, Gabbia kendricki, AMS, C.337372; A, C, E ­ H, J, K, outer side; B, D, I, L, inner side; Scales: 500 m.

FIGURE 7. Penis and accessory gland. A, D – Gabbia campicola, A, ventral view, C.332829, D, dorsal view, USNM, 803665; B – Gabbia rotunda, ventral view, AMS, C.400134; C – Gabbia davisi, ventral view, AMS, C.417617; E – Gabbia beecheyi, ventral view, AMS, C.332843; F, G – Gabbia fontana, dorsal view, AMS, C.380863; H – Gabbia spiralis, dorsal view, AMS, C.331849; I, J – Gabbia vertiginosa, dorsal view, AMS, C.203392, I, enlargement of distal end of accessory lobe; K – Gabbia adusta, dorsal view, AMS, C.203394. Scales: 500 m.

FIGURE 9. Distribution of Gabbia vertiginosa (o), G. iredalei (), G. cf. iredalei (), G. campicola (), G. fontana (), G. pallidula (☆), G. davisi () and G. rotunda (

FIGURE 10. A ­ Plot of the shell width/shell length (SWSH) against length/number of teleoconch whorls (SHTW) for two geographic sets of samples of G. vertiginosa. x – Sydney area; O – New England area. B ­ D ­ Plots of the canonical scores obtained from a discriminant function analysis using all shell measurements and whorl counts. B, x – G. iredalei; O – G. campicola; + ­ G. vertiginosa. C, x – G. aff. vertiginosa; O – G. campicola; + ­ G. iredalei; ­ G. aff. iredalei; ­ G. vertiginosa. D, x – G. davisi; O – G. campicola; + ­ G. fontana; ­ G. pallidula; ­ G. rotunda;

FIGURE 11. Radulae: A – G, Gabbia campicola, A, F, G, paratype, AMS, C.332829, B,C, MV, F.54869, D, E, AMS, C.344345; H, I, Gabbia kendricki, WAM, AMS, C.203378; A, B, half rows of teeth, C, D, F, H, central teeth, E, G, I, lateral teeth; Scales: 20 m.