Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

FNZ 3 - Anthribidae (Insecta: Coleoptera) - Systematics

Holloway, BA 1982. Anthribidae (Insecta: Coleoptera). Fauna of New Zealand 3, 272 pages.
( ISSN 0111-5383 (print), ; no. 03. ISBN 0-477-06703-4 (print), ). Published 23 Dec 1982
ZooBank: http://zoobank.org/References/AC1DC576-5021-40DE-9BD7-0F7C591C6521

Systematics

The name Anthribidae was first used by Billberg in 1820 (Arnett 1963), and is based on the genus Anthribus O. F. Mūller, 1764, of which the type-species is A. resinosus (Scopoli, 1763) . Other names by which the family has been known are Anthotribidae, Choragidae, Platyrrhinidae, Platystomatidae, and Platystomidae. Choragidae is the oldest available name for the family, but has not been used since it was proposed by Kirby (1818). Since 1820 the family name has consistently been Anthribidae, and I am following this usage for the sake of stability.

Characterisation of the family

Anthribids can be recognised as members of the superfamily Curculionoidea (Rhynchophora) by the following characters. Body usually strongly sclerotised, often clothed with scales. Head produced forwards into a rostrum, with no paired gular sutures on the underside. Antennae with the scape received into a scrobe on the side of the head, and usually with a distinct apical club. Hind coxae without a declivity or concavity against which the femora can be retracted. Tarsi 5-segmented, but 4th segment very small and almost concealed in emargination of deeply lobed 3rd segment. Abdomen with 5 ventrites and 7 pairs of spiracles.

The following assemblage of adult characters, compiled mainly from keys in Crowson (1955) and Britton (1970), separates Anthribidae from other families of Curculionoidea. Labrum distinct, separated by a groove from rest of head. Maxillae with long, flexible palps and a distinct lacinia. Rostrum flattened, not cylindrical. Antennae not elbowed (exception: somewhat elbowed in males of Hoherius new genus); club usually 3-segmented. Pronotum usually with a transverse carina and lateral carinae. Elytra with a supra-costal flange internally, and usually with a scutellary striole. Middle coxal cavities closed outwardly by mesosternum and metasternum. Tibiae lacking spurs. Tarsal claws with a tooth on inner edge. Pygidium exposed beyond elytra. First 4 abdominal ventrites fused together. Male: apex of tegmen never deeply bilobed. Female: hemisternites with an articulated apical part which has strongly sclerotised teeth and a small lateral stylus (exception: Gynarchaeus new genus, which lacks an articulated, toothed apical part and has a large apical stylus).

The most important characters of larval Anthribidae are as follows (after Anderson 1947). Body almost white, crescent-shaped, almost cylindrical, fleshy, widest in mid-abdominal region, with fleshy lateral protuberances and with few to many short or long setae on some segments. Head exserted or rarely retracted into prothorax; mouth-parts ventrally directed; epicranial suture and some setae present. Labrum with 4 or more pairs of setae. Mandibles robust, bidentate or tridentate, usually with molar areas. Maxillae with an undivided cardo, 2- or 3-segmented palps, and a setiferous mala usually bearing a thorn-like lacinia near middle of inner margin. Labium with mentum and submentum distinct; palps 1- or 2-segmented, or absent. Antennae a single, membranous segment. Anterior ocellus present or absent; posterior ocellus absent. Clypeus narrower than frons, often not distinct from it. Legs, if present, of 1-3 segments, without claws. Abdomen 9-segmented, typically with 2 folds on each segment; 9th segment smaller than 8th. Spiracles bicameral, unicameral, or without air tubes; 8 pairs on abdomen.

Arrangement of taxa

The family consists of the subfamilies Anthribinae and Choraginae, and possibly the Bruchelinae. In the past these three subfamilies have sometimes been referred to as Pleurocerinae, Anocerinae, and Urodoninae respectively. The position within Coleoptera of Bruchela, the genus on which the subfamily Bruchelinae is based, has been disputed for many years. Jordan (1925) and Wolfrum (1953) consider it to belong in Bruchidae, but later authors place it in Curculionoidea, either as a subfamily of Anthribidae (Crowson 1955) or as a separate family (Valentine 1960). Bruchelinae do not occur in New Zealand, so their taxonomic status need not be further dealt with here.

Separation of the Anthribinae and Choraginae is based mainly on the position of the antennal scrobe and the shape of the first two antennal segments, but there are also major differences in the form of the female genitalia. With their lateral or dorsolateral scrobes, almost cylindrical and bilaterally symmetrical scape and pedicel, and usually well defined rostrum the Anthribinae are more similar in appearance to other Curculionoidea than are the Choraginae, which always have dorsal scrobes, an arched, asymmetrical scape and pedicel, and an ill defined rostrum. Taking typical curculionoids as a standard, the female genitalia of Anthribinae are less modified than those of Choraginae (compare Figures 29 and 30). Because the Anthribinae seem to be morphologically closer to the generalised Curculionoidea I have placed them before Choraginae in this revision.

It is appropriate to place the New Zealand anthribine genus Gynarchaeus at the very beginning of Anthribidae because of its unmodified curculionid-type hemisternites (Figure 589). Other morphological features of Gynarchaeus that can probably be regarded as primitive rather than derived, and therefore confirm its special position in Anthribidae, are its very slight sexual dimorphism; completely lateral scrobes; simple, rather short antennae; entire eyes; only moderately long rostrum (Figure 39); relatively complete wing venation, including a closed anal cell (Figure 16); extensively sclerotised ninth abdominal segment in the female (Figure 588); large apodeme of sternite 8 in the male (Figure 291); and apparent vestiges of a pair of parameres near the apex of the tegmen in the male (see the pair of very small preapical lobes in Figure 292). By taking Gynarchaeus (Figure 39) as the starting point in the system and noting the major morphological changes that have occurred in the family it has been possible to arrange the New Zealand genera of Anthribinae in the somewhat evolutionary sequence adopted for Figures 39-60.

Morphological changes that have been regarded as significant are as follows.

  1. Either lengthening and narrowing of the rostrum to produce eventually genera such as Hoplorhaphus and Helmoreus (see successively Figures 40-44) or shortening and broadening of the rostrum to produce the sequence of genera shown in Figures 45-50.
  2. Excavation of the dorsal surface of the rostrum, at the level of the antennal insertion, so that the scrobe becomes dorsolateral or dorsal and part of its floor and sides becomes visible in dorsal aspect (Figures 52-58).
  3. Development of a notch, and subsequently a deep indentation, on the anterior margin of the eye (Figures 52-58). This modification is usually linked with the change in position of the scrobes from lateral to dorsolateral or dorsal.
  4. Lengthening of the antennae, especially in males. This change (Figures 52-60) is linked with the previous two modifications, and is frequently a feature of genera in which the rostrum shows strong sexual dimorphism (Figures 57-59).
  5. Decrease in size of the teeth and stylus at the apex of the hemisternites of the female genitalia, and movement of some of the teeth to a ventral position (Figures 32-35). In their simplest form the teeth are all rather large, similar in shape, and in the same plane, forming a large 'open hand' structure which bears a large stylus laterally (Figure 32).

Etnalis (Figure 51) can be regarded as a form of Eugonissus (Figure 50) in which the eyes have become deeply emarginate but the scrobes have remained lateral. Dasyanthribus (Figure 61) has been placed at the end of the New Zealand Anthribinae, where it forms a link between this subfamily and Choraginae. Its anthribine features are the transverse bar at the base of the body of the hemisternites (Figure 673) and the pyriform antennal scape (Figure 210), which is typical of anthribines that have a dorsolateral scrobe. However, the protruding eyes are very much like those of Choraginae, and the curved second antennal segment (Figure 211) seems to foreshadow the strongly arched choragine pedicel.

The Choraginae are much less diverse morphologically than the Anthribinae. In particular the form of the scrobes, length of antennae, development of the rostrum, and shape of the eyes are essentially the same throughout the subfamily. The five New Zealand genera are arranged in order according to the form of the female genitalia and the extent of sexual dimorphism. Liromus (Figure 62) shows very little sexual dimorphism, and the hemisternites are robust and rather like those of Anthribinae. Notochoragus (Figure 66) shows greater development of sexual dimorphism, and the hemisternites are extremely slender, with the stylus reduced to a single seta (Figures 38 and 710). The three other genera (Figures 63-65) fall between these extremes.

The arrangement of species within each genus is alphabetical.

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