Callistomorphus Perroud, 1865

Mazur, Milosz Adam, 2019, Redescription of the forgotten New Caledonian weevil genus Callistomorphus Perroud, 1865 (Coleoptera, Curculionidae, Eugnomini) with descriptions of eight new species, ZooKeys 821, pp. 45-83 : 45

Genus Callistomorphus Perroud, 1865

Callistomorphus Perroud, 1865: Perroud and Montrouzier 1865 [1864-misprint]: 169 (description); Gemminger and Harold 1871: 2449 (catalogue); Marschall 1873: 178 (catalogue); Scudder 1882: 49 (catalogue of generic names in zoology); Klima 1934: 80 (catalogue); Alonso-Zarazaga and Lyal 1999: 79 (catalogue). Type species: Callistomorphus farinosus Perroud, 1865 (by monotypy).

Diagnosis.

Distinguished from other genera of Eugnomini by the following combination of characters: rostrum elongate, longer than pronotum alone, but shorter than head and pronotum taken together; in dorsal view with distinct, polished longitudinal carina. Mandibles elongate, distinctly protruding beyond apical margin of rostrum, not exodont, overlapping. Head behind eyes distinctly constricted. Pronotum strongly narrowed before apical part with pair of various developed tubercles near middle of length. Elytra strongly scabrous with numerous, small tubercles and pair of large, elongate tubercles near middle of length (next as "middle tubercles"). Legs elongate, all femora strongly broadened, with distinct, enlarged tooth that is usually larger than half of maximum femoral width; all tibiae distinctly sinuate, without mucro in male; tarsal claws free at base, glabrous, only regularly extended basally.

Redescription.

Body length (lb) - 7.20-14.70 mm.

Body colour and vestiture (Figs 13-21). Entire body covered with strictly adjoining, small, elongate scales. Colour variable but general patterns appear stable in some species (e.g. C. farinosus Perroud). Middle of elytra usually with paler spot between the 7th and 11th elytral intervals and usually extending from one-third to two-thirds of elytral length, though sometimes shorter.

Rostrum (Figs 1, 2, 4, 5, 58-75). Elongate, almost as long as head and pronotum taken together; medially in most species with distinct longitudinal carina (Fig. 4) reaching almost to hind margin of eyes, slightly to distinctly curved in lateral view (Figs 58-66), maximum width at apical portion between antennal insertion and apex, slightly narrowing from antennal insertion to base. Scrobes partially visible in dorsal view (Fig. 4); in lateral view visible to about two-thirds of length; in ventral view dilated, not connected, evanescent before fore margin of eyes (Fig. 2). Antennae elongate; scape reaches beyond front margin of eye, funicle 7-segmented, club elongate (Figs 67-75). Mouthparts (Fig. 5) with elongate, flexible maxillae, reaching distinctly beyond front margin of rostrum; maxillary palpi 3-segmented, second maxillary palpomere distinctly elongate, third segment very short. Labial palps three-segmented, third palpomere very small, slightly protruding from second palpomere. Mentum short and wide, 3-4 × wider than long. Submentum slightly longer than wide. Mandibles strongly elongate, distinctly protruding beyond edge of rostrum; overlapping, with one apical incisor; outer edge gently rounded inwardly; inner edge smooth, without teeth.

Head (Figs 1, 2, 3a, b, 6, 58-66, 76-84). Subquadrate to transverse, distinctly narrowed behind eyes. Vertex usually with a pair of small tubercles, each furnished with bundle of scales. Eyes slightly to strongly convex, only in C. minimus sp. n. protruding above margin of head in lateral view; setae between some ommatidia short (shorter than diameter - e.g. in C. fundatus sp. n.) or elongate (longer than diameter - e.g. in C. gibbus sp. n.). Gular suture in most species visible.

Pronotum (Figs 6a, b, 40-57). With characteristic shape: broadest at base, distinctly narrowed to more or less two-thirds of length and strongly expanded apically (except C. minimus sp. n.). Apical margin in most species strongly scabrous with a few (8-10) tubercles on dorsal and lateral edge; anterior surface of pronotum forming distinct flat wall (visible in anterior view) (Fig. 6b). In lateral view, a pair of conspicuously protruding or flattened tubercles are present near midpoint (Figs 6a, 49-57). Anterior area, in lateral view, with transverse groove and sparse, shallow punctures (Figs 49-57).

Elytra (Figs 22-39). Longer than wide (el/bew 1.47-1.68) with eleven intervals. Widest at base, through the middle of well-developed humeral calli; lateral margins subparallel to ca. fourth-fifths of length before strongly narrowing to apex. Third interval, near middle of length, with distinct tubercle (except C. minimus sp. n.); height of the tubercle subequal to width of two or three intervals, the length more or less from one-third to one-quarter length of elytra. Intervals convex, in some species intervals 3, 5, 7, 9 more convex with numerous, irregular, small tubercles (flattened or acuminate). Seventh interval narrowed on short distance behind humeral angles, apically with more or less distinct tubercle (next as - posterior calli), protruding beyond outline of elytra in dorsal view (except C. minimus sp. n.); 9th interval behind humeral angles weakly protruding, clearly visible in dorsal view on this section.

Legs (Figs 7, 8, 10, 11, 12). Fore coxae contiguous (Fig. 7). Femora elongate at base and strongly broadened medially with enlarged tooth (Figs 8, 10). Tooth on fore femora with margins and apex obtuse, middle and hind with apex acute and sharp outer edge. All tibiae elongate, slender, distinctly sinuate (Fig. 10). Tarsi elongate, as long as 0.5 × length of tibiae; first tarsomere slightly longer than second, second and third of similar length. Claws untoothed, broadened basally (Figs 11, 12).

Abdomen (Figs 9a, b, 85-93, 101-107, 127-131). Subquadrate to longer than wide, al/aw 0.93-1.20. First suture fused medially, sometimes obsolete; sutures between ventrites 2-5 strongly depressed. Last ventrite short (except C. fundatus sp. n.) apically with pair of bundled, erect setae (Fig. 9a, b); in most species with shallow depressions laterally and apically between pair of erect setal tufts. Margin of last ventrite usually with distinct, sharp edge (Fig. 91). Pygidium concealed by elytra; in male generally subquadrate (Figs 101-107); in female wider than its length (Figs 127-131).

Male terminalia (Figs 94-100, 108-121). Penis (Figs 94-100) well sclerotised, distinctly curved in lateral view; basal piece (apodemal bridge) from weakly (e.g. C. farinosus ) to fully sclerotised (e.g. C. turbidus sp. n.).

Apodemes shorter than penis body; basally narrow, than distinctly extended, laterally flattened.

Tegmen (Figs 108-114). With elongate apodeme, parameroid lobes divided in different ways (detailed in description of species).

Spiculum gastrale (Figs 115-121). With elongate apodeme and divided base. Hemisternites strongly sclerotised, in most species directly connected with base of spiculum.

Female terminalia (Figs 122-126, 132-144). Abdominal tergite VIII (Figs 122-126) usually subtriangular with maximum width at base (exception - C. farinosus ). Lateral edges with conspicuous, strongly elongate setae. Spermatheca (Figs 132-134) strongly curved. Abdominal sternite VIII (Figs 135-139) with elongate apodeme and well-developed apical lobe with species-specific patterns of sclerotisation. Lateral edges of apical lobe with short, erect setae. Ovipositor (Figs 140-144) with elongate gonocoxite; styli elongate, apically with one or two bundles of elongate setae.

Sexual dimorphism. Callistomorphus is a genus with a very indistinct sexual dimorphism. Specimens within particular species vary in size and proportion of the body and values of these parameters overlap each other (Tab. 1). Both sexes have a similar last ventrite; length of rostrum and proportion of elytra are not diagnostic.

Distribution. The genus is endemic in New Caledonia, known only from the main island, Grande Terre. Localities where particular species were collected are shown in Fig. 145.

Biology. The detailed biology of species is unknown. Although other members of Eugnomini have been reared from dead wood, subcortical tissues, live stems, galls, and the leaves or fruits of many species of plants from different families (e.g. May 1987, Mazur et al. 2016), specimens of Callistomorphus were collected by beating or by sifting from the litter. Many species are suspected to have nocturnal activity, often being collected using light traps or by beating vegetation at night (see the data from the labels). According to the label data and the personal comments of Marek Wanat, members of the genus are most commonly found on plant leaves in humid and rain forest growing on limestone and/or ultramafic rocks ( Bonvallot et al. 2013), some of them only at altitudes exceeding 500 metres above sea level.

Remarks. Members of the genus are variable in terms of their size, body proportions and colour. However, they are separated from the other genera of the tribe by the set of characters presented in the above diagnosis. Many of the species are also the biggest members of the tribe. Despite their large size and characteristic body form, members of this genus are not common in museum collections or in the field. For example, during the French fieldwork conducted in the 1980s and 1990s, where fogging and standard collecting methods were used (pers. com. Hélène Perrin), no single specimen of Callistomorphus was found (see the label data of the specimens deposited in MNHN); fewer than 30 specimens of the genus were recently collected during three Polish expeditions (2006, 2008 and 2010) where a wide range of collecting methods (beating vegetation at night and day, sifting, sweep netting, light traps) were used. Most of these specimens represent new species which are described in this paper.