Yarrhpelopia Cranston 2017

Cranston, Peter S., Krosch, Matt & Baker, Andrew M., 2021, Molecular evidence for deeper diversity in Australian Tanypodinae (Chironomidae): Yarrhpelopia and related new taxa, Zootaxa 4949 (1), pp. 1-23 : 6

Yarrhpelopia Cranston 2017

Generic Diagnoses as for Yarrhpelopia ( Cranston 2017) amended as follows: Adult male.

Antennal ratio 1.7–2.0, plume may be dark or pale; pedicel with 2–4 setae; terminal antennal seta may be short and apical, or as long as the terminal flagellomere and inserted subapically ( Fig. 3A ). Wing veins with only typical setae (~ 100µ long) or may have a continuous row of 40µ long, near hyaline, blunt-ended setae ( Fig. 3B ) from base of vein R to apex of R 1. Tergite IX with sparse to many setae ( Fig. 3D ).

Adult female. Antenna with 11 flagellomeres, terminal setae shorter than to subequal to slightly longer than terminal flagellomere; Antennal ratio 0.22 ( norrisi ) or 0.29–0.31; scape with 4–6 setae, pedicel with 6–9 setae. Range of setal counts and measurable mensural characters as in male, or 15% greater. Gonocoxapodeme VIII gently curved. Gonapophysis VIII triangular, with single rounded microtrichiose lobe. Notum thin, 3x seminal capsule length. Gonotergite IX bare. Tergite IX thin, non-setose. Postgenital plate large bearing small globular cerci. Three ovoid / globular seminal capsules; spermathecal ducts bare, ending separately.

Pupa. Thoracic horn ( Fig. 2A, B , 3E, F ) ratios of length / width of horn, and plastron plate to total length of the thoracic horn vary considerably; respiratory atrium may have internal structuring ( Fig. 2B ); corona surrounding plastron plate broad ( Fig. 2A, B ) or completely lacking ( Fig. 3E, F ), horn variably spinose externally ( Figs 2A, B , 3E, F ); thoracic comb may comprise several digitiform tubercles ( Fig. 2A ), fewer short blunt tubercles ( Fig. 3F ) or, possibly, be absent. Anal lobes tapering ( Fig. 2D, E ), or squat ( Fig. 3G ).

Larva. Head shape slightly ( Fig. 2L ) to more obviously tapering. Antenna varies in lengths and proportions of terminal segments and Lauterborn organ ( Fig. 2M , 3J ). Inner teeth of ligula slightly to strongly recessed, directed near anteriorly or slightly curved outward ( Figs 2N , 3L ). Submentum with weak to strong transverse striae ( Figs. 2F, G , 3O ); arrangements of ventral cephalic setae (S9, S10, SSm) and ventral pit (VP) vary ( Figs. 2F–H , 3O ). Mandible varies in strength and intensity of pigment of apical tooth and tooth-like molar extension ( Figs. 2I–J , 3K ); some posterior parapods may have hyaline outer margin, with or without ‘flattened hook’ claw(s).

Remarks. Molecular data shows a monophyletic cluster ( Fig. 1 ) including specimens from the type locality (‘NSWCF, Captains Flat’). Intermingled are variants formerly termed ‘ST1’ (from streams polluted by sewage treatment (‘ST’) or ‘genus D’ ( Cranston 1996), from acidified, polluted or less obviously impacted sites in central Tasmania. Features that suggested their differentiation had included the pupal thoracic horn ( Fig. 2A, B ), and in the larva include the dimensions of the molar and inner teeth of the mandible ( Fig. 2I–K ), and the arrangement of setae and pits on the head capsule ( Fig. 2F, G ). From the relationships inferred in Figure 1 , we now attribute all these to intra-specific variation including some ‘variation’ caused by poor slide mounts.

The distribution previously reported as covering eastern Australia from 30°S to 42°S, with apparent absence from inland, northern and western Australia, is confirmed after increased nation-wide sampling for our molecular studies. For molecular voucher (MV) material for Y. norrisi Cranston , see Table 1. Additional material expanding original data (‘non-MV’) include as follows: New South Wales: New England, Cathedral Rock N.P., P ♂, Sphagnum swamp drain, 30°26’42”S 152°16”E 13.iii.2017; P ♀, same, except Sphagnum bog pool, 30°26’18”S 152°17’9”E; Pe, Northangera, Warrambucca Ck., 34°34’S 142°55’E, 4.i.2017; Tasmania, L, Quarry pool, 41°11’36”S 148°0’25’’E, 22.ii.2017.

Figures

FIG. 3. Yarrhpelopia acorona sp. n. Adult male.A, Antennal apex; B, Setae of wing veins R, R1; C, Spurs on tibial apex, (Left) P1 (♀), (Right) inner and outer P3 (♂); D, Hypopygium, left, dorsal (overlying ‘anal point’ omitted), right, stylised semi-ventral. Pupa. E, Thoracic horn (holotype); F, Thoracic horn, comb (Rockhole Mine Ck.); G, Dorsal abdomen; H, Tergite IV spinulation (‘shagreen’), detail; I, Anal lobe. Larva. J, Antenna, blade, apex; K., Mandible, L, Ligula, paraligulae; M, Pecten hypopharyngis; N, Maxillary palp; O, Mentum, submentum, ventral, right side dorsal. Abbreviations: S5–S10 cephalic setae, DP – dorsal pit, VP – ventral pit.

FIG. 2. Yarrhpelopia Cranston, Pupa, Larva. A–C, Thoracic horns; D, E, Anal lobes (left side only); F–H, Submenta; I–K, Mandibles; L, ventral head; M, antennal apex; N, Ligula, paraligula; O, Pecten hypopharyngis. A, E, F, Y. norrisi, type locality; B, I, Y. norrisi var ‘’ST1’; D, G, Y. norrisi var. “genus D”; C, K–O, Y. ‘V20’. Abbreviations: S5–S10 cephalic setae, DP – dorsal pit, VP – ventral pit.

FIG. 1. Phylogenetic tree from Bayesian inference for Yarrhpelopia Cranston and associated taxa (Table 1) based on concatenated gene fragments. Posterior probabilities (PP) and Bootstrap support (BS from Maximum Likelihood analysis) are indicated above branches only for nodes with PP> 0.95 or BS> 70. Maximal supported nodes are indicated with an asterisk. Likelihood bootstrap support (BS), located to the right of a PP value, are cited only if>~70%, considered as supporting that node.A dash (–) for either PP or BS indicates a value below the threshold for support; unlabeled nodes are unsupported under either criterion.