4 Ian Townsend Notes on the taxonomy of the Mecodema spiniferum species group (Coleoptera: Carabidae). J.I.Townsend, 30 B The Avenue, Levin Abstract The taxonomy of some species of the Mecodema spiniferum group is discussed with regard to variations in the shape of the apex of the mid lobe of the male aedeagus. The type locality of Mecodema fulgidum Broun as published by Britton (1949) is corrected. Mecodema constrictum Broun is reinstated from synonymy. The validity of Mecodema gourlayi is queried. The description of Mecodema oconnori Broun is expanded to include some southern North Island specimens that Britton had identified as Mecodema spinifer Broun, and also a population from the Kaikoura coast of the South Island. The chief diagnostic character which Broun used to define M. spiniferum is present on only a few specimens from the type locality. In some species extra setae are shown to occur rarely on the elytra of a few individuals within the species. Introduction The endemic carabid genus Mecodema Blanchard includes some of our largest beetles. There are 72 taxa (including species and subspecies) of Mecodema described from New Zealand to date, with further revisions to come. Britton (1949) divided the genus into eight arbitrary groups (now reduced to 7), giving emphasis to certain defined taxonomic characters which made the whole genus more manageable. The genus has not been taxonomically revised since then, although a few additional species have been described by Britton (1964), Townsend (1965), Johns (2007) and Seldon & Leschen (2011). There is still much uncertainty about the taxonomic limits of many of the species, including some of those belonging to the spiniferum species group. Having had a lifetime interest in New Zealand Carabidae, particularly The Weta 42: 4-13 5 Broscini, I have come to the heretical conclusion that the shape of the male aedeagus can vary within a species. This is not altogether surprising. These are large flightless insects with poor mobility. They tend to form discrete colonies, often restricted by altitude or habitat, for instance the populations of Mecodema costellum Broun, which remain constant in body structure but vary in the shape of the apex of the mid lobe of the male aedeagus from Gordon’s Knob, south-west of Nelson to Editor Hill in the Marlborough Sounds (Townsend, 1965). Mist often settles on these hills above 1000 metres and these large Mecodema appear to be restricted to these zones of cloud-forest, but it would be quite inappropriate to name every “microspecies” existing on these high points. The spiniferum group currently includes 18 nominal species found throughout the two main islands (Larochelle & Lariviere 2001). The species group is distinguished from other Mecodema species by the outer elytral striae being more strongly impressed and punctured than the inner striae, all the striae are clearly defined and the pronotal margins are smooth or only slightly crenulate (Britton 1949). Mecodema fulgidum Broun, 1881 Britton (1949) recorded a specimen of M. fulgidum Broun from Langridge, Awatere Valley as the type of M. fulgidum in spite of Broun (1881) clearly stating, “My two specimens were found by T.F. Cheeseman, Esq., F.L.S., on the mountains near Nelson.” Why he did this is puzzling because he also records a specimen from “Mountains near Nelson (T.F.Cheesman)” which must be a syntype. Perhaps it was in poor condition. In 2005 I saw specimens from Mt. Lyford, Inland Kaikoura which are typically M. fulgidum with both head and pronotum “smooth, unwrinkled and unpunctured”, characters that Britton (1949) correctly regarded as diagnostic of M. fulgidum so there is no doubt that M. fulgidum extends from mountains west of Nelson southeastwards into Marlborough and north Canterbury, including his “Langridge” (possibly Langleydale) specimen in the Awatere Valley. In an earlier paper (Townsend 1965) I incorrectly synonymised Mecodema 6 Ian Townsend constrictum Broun with M. fulgidum because of inconsistencies in leg colouring, but I now accept that these are both valid species on account of other characters such as elytral puncturation and aedeagal shape, (also in this case femoral colour), and here formally reinstate M. constrictum Broun,1881 from the synonymy. Mecodema oconnori Broun, 1912 Along the coastal foothills of the Seaward Kaikoura Range there is a large Mecodema species, which has all the characteristics of M. oconnori making it the first record of this species in the South Island. It is here noted from Mt. Benmore, Kekerengu; foot of Mt. Fyffe, Kaikoura; Oaro, Kaikoura; Omahi Reserve, S. of Kaikoura; and possibly the earliest record “Oaro, 25.2.47 C.E.Clarke, determined in 1957 by the late J.C.Watt as “n.sp. near M. oconnori” [AMNZ 40652]. I have examined the genitalia of this specimen and have concluded that it falls within the character range of M. oconnori. Britton (1949) identified specimens from the Hawkes Bay area as M. spinifer. In my opinion, this is not correct, they fall within the range of variation I accept for M. oconnori. This extends the range of M. oconnori into HB, GB and BP, and also north to include RI, and TO (the type area for M. validum Broun) and west to WI and TK (for symbols see Crosby, 1998). Britton (1949) also records M. spinifer from Levin but these specimens I regard as a narrow form of M. oconnori. They often have reddish femora (particularly females, but this is not a reliable character. A live specimen with red femora darkened after death to become indistinguishable from the rest of the body after eight days. Some specimens of Mecodema crenicolle Laporte de Castelnau may also have red femora (Fig. 1, photographed live at Takaka Hill, Nelson), and a common pterostichine, Plocamostethus planiusculus White usually has black legs but specimens with red legs occur in a totally random way throughout its range. Normal and red-legged forms of M. oconnori also occur within two separate populations living near Marton (WI). Red-legged forms are particularly common at Waiopehu Reserve, Levin, where some females even have red epiplura (Fig. 2) described as a unique feature of M. The Weta 42: 4-13 7 gourlayi. (Britton 1949). There is considerable variation in the thickness of the shaft and shape of the tip of the aedeagus; in some it is almost equally expanded above and below, to appear somewhat like M. simplex Laporte de Castelnau. This form is more parallel sided, the males looking similar to the females and they quite frequently have red femora. Typical M. oconnori males are larger (34 - 40 mm, mean 38) than females (31 - 38 mm, mean 34), and also have a broader thorax and elytra. Specimens from Bruce Park, Hunterville (RI) may have additional elytral setae, as well as the normal setae on the 7th interval and lateral margin. One has setae on the 1st, 3rd, 5th,7th, and 8th intervals (Fig. 3), and another from the same population has some additional setae, whereas others have the normal complement. An isolated colony of Mecodema high on the eastern slopes of Mt. Egmont at Curtis Falls is of particular interest because it has characters of both M. oconnori (transverse pronotum, ratio maximum width / mid length = 1.29) and M. validum (shallow groove on vertex) but the shape of the tip of the male aedeagus rules out that species (Figs. 4 & 5). The elytral intervals are almost flat and legs are red (Fig. 6), showing affinities with M. gourlayi and this may give a clue about the original locality of M. gourlayi Britton. Mecodema gourlayi Britton, 1949 The unique type of this species was described without knowledge of its source. Mr E.S. Gourlay (pers. comm. c.1959) told me he received his specimen from a Miss Sylvia Lysaght in Taranaki. As it happened, my father knew Sylvia and in fact had helped her collect moths on Mt. Egmont many years before. So I wrote to Dr. Sylvia Lysaght, then at the British Museum of Natural History and she said she most probably collected the specimen near her home at Ohangai, South Taranaki or on Mt. Egmont. While the specimens collected from Mt. Egmont are in my opinion closer to M. oconnori, they have some characteristics of M. gourlayi with their relatively broad pronotum, and hence the single specimen of M. gourlayi may be an extreme form of this population, or alternatively M. gourlayi 8 Ian Townsend might exist somewhere else in Taranaki. I do not know where or how Larochelle and Lariviere (2001) obtained their record of its occurrence in Fiordland. Mecodema spiniferum Broun, 1880 In describing M. spiniferum Broun states “the trochanter of the middle [leg] with a stout spine directed backwards” (Fig. 7). This is such a striking character that it is not surprising that Broun made special reference to it and used it for the basis of the species name. What is surprising is that it is not a consistent character; only some males in the population from Waitakere, the type locality, have this projection. Britton (1949), in his revision, completely ignored Broun’s reference to the trochanter. M. spiniferum is also common in Northland but there is also a spiniferum- like species at the Dome ridge between these two populations which has the mid lobe of the male genitalia ending in a round, disc-like expanded tip, totally different from the typical hook-like tip of the Waitakere and Northland specimens. It also has normal trochanters lacking a spine. I believe D.S. Seldon and R.A.B. Leschen are about to continue their revision of Mecodema by dealing with the spiniferum species group. I publish these observations so they can be incorporated into his revision where appropriate.