Antargidium dentivalve Benson

Schmidt, Stefan, 2012, Revision of the Australian sawfly genus Antargidium (Hymenoptera, Symphyta, Argidae) with description of two new species, Zootaxa 3180, pp. 47-56 : 54-55

Antargidium dentivalve Benson

( Figs 4, 5 , 10 , 20, 21)

Antargidium dentivalvis [sic!] Benson, 1934: 231 –232.

Antargidium rufum Benson, 1935: 213 . Syn. nov.

Antargidium dentivalvis: Quinlan 1974: 227 (type information); Benson 1963: 631 (classification) Antargidium dentivalve: Taeger et al. 2010: 121 .

Description. Female. Length 4–5 mm. Head orange except antenna black and ocellar region marked with brown spot. Thorax brown (rarely completely dark brown to black) with anterior part orange-yellow, including pronotum, mesoscutellar midlobe, tegula and a stripe on the mesepisternum. Legs brown except knees, tibia, tarsi of foreleg, and hind trochanter yellow-brown. Abdomen yellow with basal tergite suffused with brown. Sometimes specimens extensively yellow so that brown colour reduced to the following parts: flagellum, outer tibia and tarsus of foreleg, tibiae and tarsi of mid and hind legs. Wings slightly infuscate, veins and stigma dark brown.

Supraclypeal area with longitudinal median carina ending some distance from clypeus. Antenna slightly longer than width of head (1.1); pedicel transverse, 0.6 × as long as broad. POL slightly shorter than OOL (0.8); postocellar area about 2.0 × as broad as long. Eyes about 1.5 × as long as broad, converging below, interocular distance 1.2 × eye height. Posterior margin of hypopygium entire. Sawsheath suberect, strongly narrowed towards apex, dorsally with finger like projections ( Benson 1934, fig. 5a, b). Lancet bluntly rounded at apex, with 17 serrulae, basal 3 serrulae rounded, other serrulae serrate, proximal margin of annuli with very short and indistinct ctenidia.

Male. Length 3.5–4.5 mm. Apart from sex related differences, similar to female in structure and colour.

Host. Arytera divaricata F. Muell. , A. foveolata F. Muell. (Sapindaceae) .

Distribution. Australia: New South Wales, Queensland.

Types. Holotype A. dentivalve : Female, labelled “ Type ” [round label with red margin], “B. M. TYPE HYM 1.109.”, “ Holotype, Antargidium dentivalvis sp. nov., Ƥ, det. R. B. Benson, 1934 ”, “ Arge apicale (Kby) , det. Roh[wer].”, “R. E. Turner, 1910-225” (BMNH, examined). Paratypes: Male, labelled “Allotype” [round label with yellow margin, “Para” crossed out and replaced with handwritten “Allo”], “Queensland, Townsville, 14-ii-03, F. P. Dodd”, “R. E. Turner, 1910-225”, “Allotype, Antargidium dentivalvis sp. nov., 3, det. R. B. Benson, 1934 ” (1 3, BMNH).

Holotype A. rufum : Female, labelled “ Type ” [round label with red margin], “Tooloom, N.S.W., Jan. 1920, H. Hacker”, “T 5934”, “Genitalia mounted on a slide”, “ Holotype, Antargidium rufum sp. nov., det. R. B. Benson, 1934 ” ( QMB, examined).

Additional specimens examined. QUEENSLAND, Bowen, 20.ii.1930 (2 3, 6 ƤƤ, QDPI); Brisbane, Rafting Ground Reserve, Pullen Vale, (27.516° S, 152.882° E), 6.xii.1998, reared from larvae on Arytery foleolata, J. Grigg (1 Ƥ, QMB); 16 km N Boonah (27.90° S, 152,68° E), 17.ix.1994 and 15.xii.1996, C. J. Burwell (1 3, 2 ƤƤ, QMB; 1 Ƥ, ZSM); Mount Scoria, 6 km S Thangool (24.533° S, 150.600 E), 1.i.1991, G. and A. Daniels (1 Ƥ, QMB); Townesville, 14.xi.1903, F. P. Dodd (1 Ƥ, QMB); Cape York, 1868, Thorey (1 Ƥ, NHMW); Toogoom, 11.x.1979, H. E. & M. A. Evans, A. Hook (1 3, QMB); Boonah, 15.ii.1947, Mosser (1 3, QMB); Townesville, D. & H. Priestly (1 Ƥ, QMB); Imbil, 27.i.1928 [?], Q. R. B. (1 3, QDPI); Brookfield (27.466°S, 152.883°E), 17.i.1999, ovipositing on Arytera divaricata, J. Grigg (3 ƤƤ, QMB; 1 Ƥ, ZSM). NEW SOUTH WALES, Tooloom, Jan. 1920, H. Hacker (1 Ƥ, BMNH).

Remarks. The colour of A. dentivalve is variable. The colour of the thorax in particular ranges from almost completely yellow-brown to completely dark brown (to black). In the majority of specimens the thorax is brown with the anterior parts yellow. Some specimens are almost completely yellow-brown with only antenna, mandibles, and tibiae and tarsi brown, and were described by Benson as A. rufum . However, the extent of brown colour is highly variable and no morphological characters could be found that would support the notion that yellow specimens represent a distinct species. Benson had to rely on very few specimens for his descriptions which did not allow him to see the amount of colour variation that is present in the species.

Taeger et al. changed the specific epithet from dentivalvis to dentivalve in an attempt to meet the gender agreement required by Article 31.2 of the Code of Zoological Nomenclature ( CZN 2001). However, there is no clear indication that Benson regarded the name as adjective and not as noun in apposition. On the contrary, there is evidence of usage that Benson regarded the epithet as a noun because he described other Antargidium species with correct gender ending (e.g. A. allucente , A. apicale ).

Although Benson treated his name in the dative case which is not permitted (Article 11.9), the name dentivalvis should be regarded as an incorrect original spelling that is to be preserved (Article 32.5). Since the Code requires retaining a name if it can be regarded either as noun or as an adjective, the Code (Article 31.2.2) suggests retaining the original spelling. However, for the sake of stability, the name change by Taeger et al. is here accepted, combined with a plea for not changing names that have been in usage for over 70 years, even if they are regarded to be incorrect, and in particular if the intention of the author can be derived unambiguously from the original description.

Figures

FIGURES 1 – 7. Antargidium spp., 1 – 2 face, 3 – 4: vertex, 5: apex of abdomen, 6: female hypopygium, 6: sawsheath. (1, 6) A. allucente; (2) A. atriceps; (3, 7) A. flavescens holotype; (4, 5) A. dentivalve. Abbreviations: S: supraclypeal area, K: carina, P: dorsal projections.

FIGURES 8 – 13. Antargidium spp., 8 – 2: females in lateral view, 13: apex of abdomen and sawsheath in lateral view. (8) A. allucente; (9) A. atriceps; (10) A. dentivalve; (11) A. flavescens holotype; (12) A. nigrum holotype; (13) A. apicale.