Melobasis, Laporte & Gory, 1837

Levey, Brian, 2012, 3464, Zootaxa 3464, pp. 1-107 : 12-15

Key to the species-groups of Australian Melobasis

Because some species-groups are easily keyed, I have thought it better to provide a key to species-groups and separate keys to the species of each group, rather than one very long key to species which I think would increase the chances of misidentification.

The variation within species-groups has meant that some species-groups have had to be taken out several times in the key. The species-group key will not necessarily enable non Australian species to be assigned to the speciesgroup to which they are most closely related. I have tried not to use characters of the male genitalia or secondary sexual characters as the only distinguishing characters, however, in a few cases where they are the most reliable characters they are used, and in some cases they are the best way to confirm that a species has been traced to the correct species-group.

If a species does not unambiguously key to a species-group it may be an undescribed species or possibly a variation of a described species which I have not seen. The habitus images, use of the separate keys to species and examination of the male genitalia, if available, should help to resolve this problem if it arises.

1 Epipleura of elytra with a small tooth, or strongly and abruptly narrowing opposite the hind coxae (Figs.14,15); lateral carina of pronotum reaching or almost reaching the pleurosternal suture; elytral punctation longitudinally seriate, except sometimes close to the lateral margin; mesoepisternum at least weakly microreticulate, usually without or with very few punctures away from the margins; apices of parameres of aedeagus with fine, long setae only; flange of apical sternite in male not produced at centre......................................................................... paramelobasis group (part)

- If epipleura of elytra slightly narrowing opposite the hind coxae ( Fig. 16); then without all the other above mentioned characters combined................................................................................... 2

2 Scutellum shaped like an oblate semicircle, large, about one-ninth to one-fifth width of elytra at base; pronotum widest at base, more or less trapeziform, the anterior margin not, or scarcely produced at the centre ( Fig. 28); mesoepisternum smooth or weakly microreticulate, unpunctured or with a few large, shallow setae-bearing punctures ( Fig. 39); elytra punctate-striate; apices of parameres of aedeagus with fine, long setae only; flange of apical sternite in male not produced at centre............................................................................................... diceropygus group

- If scutellum shaped like an oblate semicircle, then not more than one-tenth width of elytra at base and/or prontum not widest at base................................................................................................ 3

3 Each elytron with two or more large, irregular depressions; pronotum with large, well defined, elongate depressions near the lateral margin ( Fig. 17); lateral carina of pronotum straight, meeting the pleurosternal suture anteriorly; mesoepisternum densely punctured with small irregularly shaped punctures ( Fig.40); flange of apical sternite in male not produced at centre.......................................................................................... abnormis group

- Without the above combination of characters................................................................ 4

4 Frontoclypeal margin strongly angulate lateral to the excision ( Fig. 19); apices of elytra slightly spatulate; elytra internal to the 1st costa weakly, sparsely punctured, strongly, contiguously punctured external to the 1st costa; body navicular ( Fig. 18)........................................................................................... nobilitata group

- Without the above combination of characters................................................................ 5

5 Tarsal claws with broad posterior tooth, or strongly appendiculate at base ( Fig. 20)................................... pusilla group (part)

- Tarsal claws not toothed, at most only slightly widened at base ( Fig. 21)......................................... 6

6 Lunate punctures at side of apical sternite coalescent, their rims forming ridges more or less parallel to the lateral margin, or more rarely forming concentric semicircular ridges (part of formosa group) ( Figs. 8, 9)............................ 40

- Lunate punctures at side of apical sternite separate or more rarely contiguous, the rims not coalescing to form ridges ( Figs. 6, 7) 7

7 Flange of apical sternite wide, the lateral spines short, not longer than the width of the flange ( Fig. 22); prosternal process with at least sparse, obvious opaque white pubescence, or with very long outstanding silvery pubescence on head, the setae only turning down at the tip ( M. rectipilosa sp. n.).................................................. propinqua group

- If flange of apical sternite as wide as above then prosternal process without obvious pubescence or pubescence translucent, silvery and pubescence on head not as above................................................................ 8

8 Prosternal process with a line of coalescent punctures near the lateral margin, sometimes only present at the base ( Figs. 26, 27); flange of apical sternite wide, the lateral spines short, not longer than the width of the flange (e.g. Fig. 23,); mesoepisternum densely punctured with large, shallow punctures, partly obscured by setae ( Fig. 37)................ .. formosa group (part)

- Without the above combination of characters................................................................ 9

9 Flange of apical sternite wide, almost filling the excision between the spines ( Fig. 25); anterior margin of pronotum strongly produced at centre; base of elytra strongly biangulate or biarcuate ( Figs. 29, 30); mesoepisternum shiny or microreticulate, sparsely to densely punctured with small punctures ( Fig. 38), or microreticulate with a few large setae-bearing punctures in the anterior, inner corner.................................................................................. 10

- If flange of apical sternite almost as wide as above then mesoepisternum densely punctured with large setae-bearing punctures (Fig. 44)............................................................................................ 11

10 Base of elytra strongly biangulate, the elytra wider at base than pronotum at base ( Fig. 29); tergite 9 in female with a fringe of long curved hairs at the distal margin ( Figs. 31, 32) thoracica group

- Base of elytra strongly or very strongly biarcuate, the elytra not or scarcely wider than pronotum at base ( Fig. 30); tergite 9 in female without a fringe of long curved hairs at the distal margin................................. gloriosa group (part)

11 Antennal cavities forward facing, and / or the frontoclypeus very reduced ( Figs. 33, 77, 79)........... aclypea group (part)

- Antennal cavities not forward facing, partly concealed when the head is viewed from the front, the clypeus less reduced ( Figs. 34, 35, 36).......................................................................................... 12

12 Elytra entirely blue or violet; pronotum reddish-copper, sometimes broadly blue or blue-green in the middle; elytral punctation arranged in regular longitudinal series, except near the lateral margin............................... azuripennis group

- Colour not as above; elytral punctation variable............................................................ 13

13 Elytra reddish-purple to almost black, with a green or golden sutural vitta, short humeral vitta and long lateral vitta (Fig. 47); vertex with obvious pubescence; aedeagus very elongate, the median lobe prolonged at the apex, the parameres with stout setae in addition to the usual fine setae (Figs. 45, 46); N. Queensland ................................... brooksi group

- Colour pattern not as above; aedeagus less elongate......................................................... 14

14 Dorsal margin of hind tibia strongly sinuate, with a very dense fringe of setae in the apical half (Fig. 48); mesoepisternum shiny with punctures only at the margin ( Fig. 39); prosternal process without a line of coalescent punctures near the lateral margin.................................................................................. andersoni group

- Without the above combination of characters............................................................... 15

15 Clypeus with a deep, narrow excision ( Fig. 36); scutellum very small, triangular, about one-twentieth width of pronotum at base; each elytron with eight well defined rows of seriate punctures; mesoepisternum smooth and shiny, with at most only a few medium sized shallow punctures present (39).......................................... prolongata group (part)

- Clypeus with a less deep, broader excision, if fairly deep then without the other characters combined.................. 16

16 Mesoepisternum shiny with none to many large shallow setae-bearing punctures present ( Figs. 39, 44)................ 17

- Mesoepisternum with the surface more or less covered with small variably shaped punctures, sometimes also partly microreticulate ( Figs. 40, 41, 43)........................................................................ 33

17 Elytra with well defined vittae, fasciae or maculae.......................................................... 18

- Elytra without vittae fasciae or maculae, although sometimes the suture, apical or lateral margins may be differently coloured to the rest of the elytra................................................................................. 22

18 Elytra with at most only one or two rows of well defined seriate punctation lateral to the subsutural depression.......... 19

- Elytra with at least four rows of well defined seriate punctation lateral to the subsutural depression.................... 20

19 Elytra with the humeral and sutural vittae extending from base about one-quarter length of elytra; elytra with at least one well defined costa and often trace of two more ( M. similis sp. n.).................................... gloriosa group (part)

- Elytra with the humeral vitta not extending beyond the humeral callosity, the sutural vitta only about one-sixth the length of the elytra; elytra with only a trace of one costa obscurella group (part)

20 Aedeagus with only fine long setae on the apical part of the parameres (Fig. 50); elytra without a pre-apical macula............................................................................................. ignipicta group (part)

- Aedeagus with stout spine-like setae, which are sometimes very small and inconspicuous, in addition to the normal fine long setae on the apical part of the parameres (Figs. 51, 52); elytra with a pre-apical macula, but sometimes lacking a median fascia ................................................................................................... 21

21 Mid tibia of male swollen, with a setae-filled depression on the underside (Fig. 49)................. pretiosa group (part)

- Mid tibia of male not swollen, without a setae-filled depression on the underside.................. hypocrita group (part)

22 Prosternum strongly raised for its whole width relative to the beaded anterior margin (viewed from front), sometimes with tubercules at the side (Fig. 53) buprestoides group (part)

- Prosternum not or scarcely raised, or only raised at centre relative to the beaded anterior margin...................... 23

23 Prosternal process with a groove or line of coalescent punctures near the lateral margin at least at the base ( Figs. 26, 27)... 24

- Prosternal process without a groove or line of coalescent punctures near the lateral margin.......................... 28

24 Apices of elytra acute, the most apical tooth obviously larger than those between it and the suture (Fig. 54)............. 25

- Apices of elytra more or less rounded, the most apical tooth not or scarcely larger than those between it and the suture (Fig. 55)................................................................................... ignipicta group (part)

25 Punctation of lateral quarter of elytra tending to form short transverse series, not arranged in regular longitudinal series (Fig. 56)................................................................................................ 26

- Punctation of lateral quarter of elytra not forming transverse series, mostly arranged in regular longitudinal series (Figs. 57, 58) ................................................................................................... 27

26 Elytra blackish-green or blackish-lilac; pronotum blackish-green, blackish-lilac or purple in central half, reddish- to greenishcopper in lateral half; punctation of lower two-thirds of head consisting of very uniformly sized small punctures, the surface between the punctures strongly microgranulate, not shiny ( Fig. 35) hypocrita group (part)

- Elytra brownish-bronze, golden or golden-green; pronotum entirely brownish-bronze, golden or golden-green; punctation of lower two-thirds of head consisting of less uniform slightly larger punctures, the surface between the punctures not or only very weakly microgranulate, shiny ( Fig. 34) nervosa group (part)

27 Interstrial punctures in lateral quarter of elytra very tiny, much smaller than those forming the regular longitudinal series (Fig. 57)............................................................................... prolongata group (part)

- Interstrial punctures in lateral quarter of elytra about half the size of those forming the regular longitudinal series (Fig. 58)...................................................................................... ignipicta group (part)

28 Punctation in lateral quarter of elytra mainly arranged in regular longitudinal series (Figs. 57, 58) or elytral apices broadly rounded (Fig. 55); elytra without well defined costae or costate interstriae........................................ 29

- Punctation in lateral quarter of elytra mainly arranged in short transverse series (Fig. 56); elytral apices acute or subacute (Figs. 54, 59); elytra with well defined costae or costate interstriae................................................... 31

29 Elytral apices broadly rounded (Fig. 55); antero-lateral corner of pronotum with some conspicuous long pubescence..................................................................................... paramelobasis group (part)

- Elytral apices acute or subacute (Fig. 54, 59); pronotum without any conspicuous long pubescence................... 30

30 Most apical tooth of elytra enlarged, larger than the teeth between it and the suture (Fig. 54); elytra unicolourous blackish- or dark brownish-bronze................................................................. hypocrita group (part)

- Elytra without an enlarged apical tooth; elytra blackish-green or reddish-purple with a coppery red median macula or fascia, which may be small or rarely absent...................................................... ignipicta group (part)

31 Elytral apices acute with an enlarged apical tooth (Fig. 54); lateral margins of pronotum gradually convergent to the apical angles (Fig. 60); excision of apical sternite with the distal margin of the flange straight hypocrita group (part)

- If elytral apices somewhat acute, with a slightly enlarged tooth then lateral margins of pronotum more abruptly convergent to the apical angles (Fig. 61), and excision of apical sternite in male with the distal margin of the flange bisinuate or produced at the centre......................................................................................... 32

32 Punctures of central quarter of pronotum mostly tiny, pin-prick type (Fig. 62); lateral margins of pronotum gradually convergent to the apical angles (Fig. 62); excision of apical sternite with the flange not produced at the centre................................................................................................. ignipicta group (part)

- If punctures in central quarter of pronotum partly pin-prick type then lateral margins of pronotum more abruptly convergent to the anterior angles and excision of apical sternite in male with the flange produced at the centre....... nervosa group (part)

33 Prosternal process with a groove or line of coalescent punctures close to the margin, no punctures reaching the lateral margin ( Figs. 26, 27)........................................................................................ 34

- Prosternal process without a groove or line of coalescent punctures close to the margin, sometimes with some punctures reaching the lateral margin............................................................................. 38

34 Elytra with median and pre-apical maculae or fasciae....................................................... 35

- Elytra without median and pre-apical maculae or fasciae..................................................... 36

35 Elytra without humeral maculae or vittae; median fasciae or maculae separated from the lateral margin of the elytra by at least two-thirds its own width............................................................... hypocrita group (part)

- Elytra with a humeral maculae or vittae, often extending along the basal margin to fuse with the scutellary vitta; median fasciae at most separated from the lateral margin of the elytra by one-quarter its width..................... pretiosa group (part)

36 Elytral apices acutely angled (Fig. 54)..................................................... hypocrita group part

- Elytral apices obtusely angled or rounded (Figs. 55, 59)...................................................... 37

37 Mesoepisternum strongly microreticulate, sometimes with some small punctures over part of the surface (Fig. 41)............................................................................................ obscurella group (part)

- Mesoepisternum shiny not microreticulate and more or less densely punctured with small variously shaped punctures ( Fig. 40).................................................................................... pretiosa group (part)

38 Head clothed with sparse to dense long pubescence......................................... cupricollis group (part)

- Head glabrous....................................................................................... 39

39 Elytra usually with the following green, golden-green or blue-green markings: a sutural vitta of variable length, an oblique vitta extending from the base over the humeral callosity, a lateral vitta extending from the base, of variable length; in some specimens the markings are enlarged and coalescent and in extreme cases most of the elytra is green, golden-green or bluegreen; median lobe of aedeagus with an elongate acute apex (Fig. 63) vittata group

- Elytral markings very variable, however, rarely as above, usually with at least a small macula in the apical half, and if an oblique humeral vitta is present, it is confined to the basal half of the elytra; sometimes the markings are enlarged and coalescent and such specimens are most easily distinguished from those of the vittata group in having the apex of the median lobe of the aedeagus subacute or approximately diamond shaped (Fig. 64)......................... purpurascens group

40 Apical sternite with a median carina in the apical half, the ridges formed by the coalescent punctures strongly turned in towards the carina, excision in male with the flange produced at the centre (Fig. 69); median lobe of aedeagus with the apex shaped like an arrowhead, the parameres with short stout setae as well as long fine setae (Figs. 65, 66).................... lauta group

- Without the above combination of characters............................................................... 41

41 Distal margin of clypeus with a narrow excision between broad lateral lobes, or with a broad V-shaped excision (Figs. 73, 74, 75, 76).................................................................................. melanura group

- Distal margin of clypeus not as above..................................................................... 42

42 Distal margin of clypeus almost straight or very shallowly emarginate, sometimes with a small median projection (Figs. 77, 78,), and/or antennal cavities forward facing (Fig. 79, 80)....................................... aclypea group (part)

- If distal margin of clypeus only shallowly emarginate then not produced at the centre and antennal cavities downward facing ( Figs. 34, 35, 82) 43

43 Apical sternite with the excision largely or entirely filled by the flange, not produced at the centre in the male ( Figs.207–212); mesoepisternum densely punctured with large, shallow setae-bearing punctures ( Fig. 37); clypeal excision broad, moderately deep, U-shaped (Fig. 81); length greater than 9mm ........................................... formosa group (part)

- Apical sternite with excision not largely filled by the flange; if flange fairly broad then mesoepisternum microreticulate with at most a few large, shallow punctures present (Fig. 42); clypeal excision shallow and length less than 9mm ............... 44

44 Mesoepisternum densely punctured with small variously shaped punctures, large shallow, setae-bearing punctures absent ( Fig. 40)............................................................................... cupricollis group (part)

- Mesoepisternum strongly microreticulate, sometimes with a few large, shallow setae-bearing punctures present (Fig. 42), or more or less densely punctured with large shallow setae-bearing punctures (Fig. 44), and sometimes in addition some small punctures or weak microreticulation..................................................................... 45

45 Mesoepisternum not obviously microreticulate, with few to many large, shallow, setae-bearing punctures present (Figs. 44)...................................................................................... nervosa group (part)

- Mesoepisternum strongly microreticulate (fig. 42), sometimes with a few large, shallow, setae-bearing punctures, and small punctures present..................................................................................... 46

46 Prosternal process almost twice as long as wide at the widest point, parallel sided or at most weakly widening posteriorly (Figs. 70, 71, 147); clypeus broadly shallowly emarginate with rounded or obtusely angled peaks (Fig. 82); scutellum fairly large, about one-twelfth to one-fourteenth the width of elytra at base; excision of apical sternite with a straight flange in both sexes; aedeagus short, the apex of the median lobe simply acute ( Figs. 160, 161, 162, 163); length 6mm or less...................................................................................................... pusilla group (part)

- Prosternal process about one and a half times as long as wide at the widest point, strongly widening posteriorly (Figs. 72); clypeal peaks of various shapes, however, not as broadly rounded as above; scutellum small, less than one-twentieth the width of the elytra at the base; excision of apical sternite with the flange at least slightly produced at the centre in both sexes; aedeagus elongate, the apex of the median lobe rarely simply acute usually asymmetrical (Figs. 67, 68); length usually greater than 6mm ................................................................................ iridicolor group