Nemonychidae

Oberprieler, Rolf G., Marvaldi, Adriana E. & Anderson, Robert S., 2007, Weevils, weevils, weevils everywhere *, Zootaxa 1668, pp. 491-520 : 497-499

Nemonychidae

This family of weevils (fig. 1) retains numerous primitive traits, both in structure and in habits. It is a relict group of the ancient past, today comprising only about 76 known species (71 described) in 21 genera but with a rich fossil record of about 60 species from Upper Jurassic and Lower Cretaceous deposits largely in the northern hemisphere. The extant fauna shows a highly disjunct distribution mainly in temperate northern and southern regions but with some species also in the tropics. It is most diverse in the Australian and Neotropical regions, which harbour about 70% of the fauna, fewer species occurring in the Nearctic and Palaearctic regions. Nemonychidae are predominantly associated with conifers, especially the family Araucariaceae , which hosts half of all the species, while Pinaceae provide the common hosts in the northern hemisphere. Only two genera live on angiosperm hosts, Rhynchitomacer on Nothofagus (Nothofagaceae) in South America and Nemonyx on Consolida and Delphinium (Ranunculaceae) in the western Palaearctic. The association with conifers (especially Araucariaceae ) is likely the ancestral one and the angiosperm associations to represent secondary host shifts. The Nemonychidae are presumed to retain the ancestral life style of weevils, their mobile larvae living freely (ectophytically) among the sporophylls inside dehiscing male conifer strobili (cones), feeding on pollen in the open sporangia (pollen sacs) and moving between cones. Eggs are laid openly between the sporangia by means of the ovipositor ( Howden 1995), but the females of some species may use their elongated rostrum to separate sporophylls before the cope ripens, allowing them to lay their eggs inside the cone against the sporangia. A few forms, however, such as Bunyaeus and Eutactobius in Australia and Brarus in South America, have a short to very short rostrum, and Nemonyx females use their hard, piercing ovipositor to drill holes into the follicles of the host fruits, in which their larvae feed on the developing seeds. Adult nemonychids also feed mainly on pollen.

The Nemonychidae are classified into three subfamilies, Nemonychinae (for Nemonyx only), Rhinorhynchinae and Cimberidinae . Nemonyx differs from all other genera in a number of characters, many of them plesiomorphic ( Kuschel 1995), which prompted Crowson (1985) to argue for placing it in a family of its own. However, Kuschel (1994, 1995) and May (1994) identified pertinent imaginal and preimaginal synapomorphic characters that hold all nemonychids together as a single family. Nemonyx nonetheless shows the greatest number of plesiomorphic traits of all extant weevils.