La Decisión del Consejo de 26 de julio de 2010 por la que se establece la organización y el

Estimates of diversification dates vary considerably. When fossil calibrations are used, the rate of evolution of COI and 28S are an order of magnitude lower than those reported by Papadopoulou et al.(2010). When dates are based on calibrating the rate of molecular evolution, the estimated ages are, correspondingly, an order of magnitude younger.

The first of two possible geological calibrations between sister species involves the two sister species pairsC. rhesus/C. navicularis andAl. longi-

collis/Al. oleariphagus. In both pairs, the former is found in the Canterbury

foothills while the latter is restricted to Banks Peninsula. Additionally, C.

rhesus also is found in the Port Hills in an apparent recent colonisation of

Banks Peninsula. The formation of Banks Peninsula, originally as an off- shore island, began around 15 mya, with significant volcanic activity between 11–6 mya forming the Lyttleton, Mt Herbert, and Akaroa volcanoes. Vol- canism decreased substantially 6 mya, and there has been no activity since 5 mya (Bradshaw & Holland, 2008). The activation of the Alpine Fault, and subsequent mountain building around 5 mya began the formation of the Canterbury Plains. Through the deposition of alluvial material, partic- ularly during glacial periods, the Canterbury Plains developed over the past 2 mya, potentially only reaching the Peninsula as recently as 20 000 years ago (Forsyth et al., 2008). Based on these dates, crown ages of these two species pairs is more accurately given by the fossil calibrated dates than the rate calibrated dates.

The second possible geological calibration are the two sister species pairs

the former species is found around Wellington in the southern North Island, while the latter species inhabits opposite side of Cook Strait in the Marl- borough Sounds (northern South Island). Palaeogeographic reconstructions of the formation of Cook Strait indicate that the Wellington region was connected to the Marlborough area until relatively recently, separating only within the last 2 my (Bunceet al.,2009;Lewiset al.,1994;Trewick & Bland,

2012). Based on these dates the crown ages of these two clades, which are reasonably congruent, is more accurately given by the rate calibrated dates than the fossil calibrated dates.

The single fossil used in this study for calibrating the age of the Entim- inae ingroup is likely to be only distantly related to the taxa included, and therefore is likely to result in an older inferred age of theBrachyolus group than in reality. Greater taxon sampling within the wider Entiminae at the global scale, using more of the available entimine weevil fossils as calibra- tion points (Yunakov & Kirejtshuk, 2011), and using geological calibration points in outgroup taxa (Sequeiraet al.,2008a) will be necessary to obtain better estimates of the timing of New Zealand entimine weevil diversifica- tion. However, this work is hampered by the lack of DNA sequence data for a wide range of Entiminae, though more are likely to become available in the near future (N. Gunter, V. Pereyra pers. comm).

Applying na¨ıve molecular clock rates to interspecific genetic distances is a quick and readily calculated value that appears to give reasonable estimates for relatively recently diverged clades. However, there is a limit to their utility. Completely unrelated sequences have a maximump-distance of 0.75 due to the coding system of DNA, but constraints on gene functions make sequence saturation an issue before this point (Xia et al., 2003). Applying the COI na¨ıve molecular clock rates to sequences with this maximum degree

of divergence results in estimates of 21–50 mya. The use of na¨ıve molecular clocks in the context of investigations into the origin of New Zealand taxa are therefore likely to underestimate the age of New Zealand clades, and increase a Type II error of not rejecting a null hypothesis of recent dispersal. In the New Zealand Entiminae, the fossil calibrated dates are more congruent with the estimates of a na¨ıve molecular clock. Rate calibrated dates were more recent than most of the na¨ıve dates estimated by applying the fastest molecular evolution rates. The pairwise genetic distances between species and genera within the New Zealand Entiminae are rather low, compared with other Entiminae (e.g. maximum distance of 0.281 in Galapaganus,

Sequeiraet al. 2000a).

To summarise, greater reliance is to be placed on the date estimates from the rate-calibrated dataset. This is based on the congruence of these dates with the opening of Cook Strait and colonisation of alpine regions, the closer match in the time to speciation with wider studies, and is consistent with the estimated ages of clades with significant patterns of non-monophyly be- ing less than 1–2 mya. Calculating the date of origin of each genus using a molecular clock, thus resulted in estimated crown ages of 3.78–6.04 mya for

Irenimus, 1.44–3.13 mya for Austromonticolus, 2.21–4.12 mya for Alocom-

matus and 4.42–7.00 mya forChalepistes. These are recent, compared with

other Entiminae genera. Phyllobius and Polydrusus are both known from fossils dated to the Eocene (55–35 mya), whileOtiorhynchus andHormorus

are known from Upper to Middle Miocene fossils (20–12 mya) (Yunakov & Kirejtshuk, 2011). Molecular dating for Galapaganus estimated the origin around 12 mya (Sequeiraet al.,2008a). However, these dates are consistent with estimates of the age of Ectemnorhinini, which have been calculated as diverging within the past 6 my (Grobleret al.,2011b).