Myrmecia banksi, Taylor, Robert W., 2015

Taylor, Robert W., 2015, Ants with Attitude: Australian Jack-jumpers of the Myrmecia pilosula species complex, with descriptions of four new species (Hymenoptera: Formicidae: Myrmeciinae), Zootaxa 3911 (4), pp. 493-520 : 501-503

Myrmecia banksi sp.n.

( Figs 4–6)

Myrmecia banksi is known only from low elevations along a narrow coastal and sub-coastal strip in NSW south from Sydney to Batemans Bay.

This species was referred to in previous JACP publications as the "greenhead" form of M. ( pilosula ), as “ M. ( pilosula ) 2n=10”, or informally as “ M. banksi ”.

Type locality. NEW SOUTH WALES: South Nowra, shortly north of the junction of Forest Road and Bulldog Avenue track (-34 56, 150 37), ca 800 meters west of the Forest Road/Princes Highway intersection. Forest Road marks the boundary between Currambene State Forest (to the North) and Nowra State Forest. The area is referred to locally as Comberton,

Type deposition. Holotype and paratypes in ANIC, paratypes or type-compared vouchers in AMSA, MVMA, QMBA, SAMA, WAMA, TMHA) and in BMNH, CASC, MCZC, MHNG.

Material examined, distribution. Known from coastal or sub-coastal NSW, from Leumeah, Sydney, south to Catalina, Batemans Bay. All collections are from elevations below 70 meters. Localities most distant from the coast are at Wandandian (ca 5km inland) and Leumeah (ca 24 km). Myrmecia banksi will almost certainly range further north and south, and could occur more widely in the Sydney area where records of Jack-jumpers are currently sparse.

JACP and AAVAS records. NEW SOUTH WALES: Leumeah, E of railway station [-34 0 3, 150 50], HI–AAGR13, AAGT11; Nowra [-34 53, 150 36], HI87–122–127, 91–057; South Nowra [-34 55, 150 36], HI99–013; AAVAS accessions 145, 147, 148, SB&SM; Wandandian [-35 5, 150 31], HI89–034, HI91–048, 100, 101; West of Nelligen [-35 39, 150 8], HI85–213, HI91–191; Sheep Station Creek near Nelligen [-35 39, 150 8], HI87–158; Batemans Bay [-35 42, 150 11], HI87–160; Catalina [-35 43, 150 11], AAVAS. The JACP “Nowra” samples were collected near HMAS Albatross Naval Air Station; the “South Nowra” records from the vicinity of the type locality; and the Batemans Bay sample from near the western end of Maloneys Beach.

Worker diagnosis. General features as illustrated and in key couplets 1, & 3 above. Myrmecia banksi is distinguished within the pilosula complex by its dense, brassy-green cephalic pubescence. This produces strong greenish-yellow reflections, readily visible in living specimens with hand lens magnification, and encouraged Imai’s field epithet “greenhead”. Anterior femora chocolate brown, each with a reddish-orange apical section up to 1/3 its length, matching the adjacent tibia. Middle tarsi and tibiae reddish-orange, matching those of fore legs. Hind femora and tibiae dark brown, like anterior femora; the tibiae sometimes a little lighter, with their apices and the tarsi progressively lighter in color towards the foot. Myrmecia banksi is otherwise morphologically similar to the eastern species Myrmecia impaternata and the Western Australian M. imaii , which have similar but usually muchless dense brassy cephalic pilosity, and distinctive, very different karyology (see below). The provenance of specimens and their comparison with confidently identified vouchers is important in differentiating these taxa.

Dimensions. (Holotype, smallest paratype, largest paratype (mm): TL = 13.04, 11.81, 13.45; HW = 2.66, 2.26, 2.76; HL = 2.44, 2.48, 2.77; CI = 109, 109, 111; EL =1.02, 0.87, 1.06; OI = 38, 38, 38; SL = 1.98, 1.75, 2.09; SI = 74, 77, 76; PW = 1.72, 1.70, 1.77; WL = 3.86, 3.33, 3.92; PetW = 0.94, 0.77, 1.01; PpetW = 1.50, 1.19, 1.60.

Etymology. Named for Joseph Banks (1743–1820) who with Daniel Solander in 1770 first scientifically collected Australian ants and other insects at Botany Bay, NSW, while exploring ashore from James Cook’s HM Bark Endeavour in habitat similar to that at the M. banksi Type Locality. The Endeavour landing site is about 100km NNE of the M. banksi South Nowra site.

Karyology. Most examined specimens (sampled from all above localities except Catalina and Batemans Bay) had the monomorphic karyotype 2K=6M +2M c +2A (2n=10) (Imai, Taylor et al., 1994: 147, Fig. 5 h). One putative mutant individual from Leumeah (sample HI–AAGH–11) had a complicated translocation producing 2n=9 (Imai, Crozier et al., 1977).

Notes. S ympatric associations with other M. pilosula -complex species are unknown. Convincing karyological evidence identifies M. banksi (or a close ancestor) as one of the parent species of the apparently parthenogenetic and hybrid-originated M. impaternata (the other putative parental taxon is an element of the Eastern Race of M. pilosula : see below under M. impaternata ). Because of close similarity between M. banksi and M. impaternata future studies, such as analysis of their distributional relationships between the NSW South Coast and Southern Tablelands, might require karyological or DNA analyses to authenticate identifications. A winged male is present in HI87–123. Myrmecia pilosula (Eastern Race) is considered likely to be found in future as a sympatric associate of M. banksi .

Research prospects. See below under M. impaternata .