Calacalles (Nanoacalles) hermigua Stüben & Astrin, 2009

Astrin, Jonas J. & Stüben, Peter E., 2009, Molecular phylogeny in ' nano-weevils': description of a new subgenus Nanoacalles and two new species of Calacalles from the Macaronesian Islands (Curculionidae: Cryptorhynchinae), Zootaxa 2300, pp. 51-67 : 63-64

Calacalles (Nanoacalles) hermigua Stüben & Astrin sp.n.

( Figs. 3 , 6, 8 , 17 )

Type material. Holotype. 3: SPAIN, Canary Islands, La Gomera, SE Hermigua , near Casas del Palmar, thermophilous shrub forest, Asteraceae : Sonchus , N28°09'30" W17°09'46", 650 m, 31.12.2004, leg. Stüben ("27"), coll. Curculio-Institute Mönchengladbach.

Paratypes. 73, 7Ƥ: data as for holotype, coll. Stüben, coll. Curculio-Institute Mönchengladbach (1Ƥ); 13, 4Ƥ: data as for holotype, 8.10.2008, leg. Astrin & Stüben (“21”), coll. Stüben, coll. ZFMK (13, 1Ƥ).

Further material. 83, 8Ƥ: SPAIN, Canary Islands, La Gomera, Bosque del Cedro, Ermita de Lourdes, 900 m, laurel forest, 25.12.1998, leg. Stüben (“2”), coll. Stüben; 2Ƥ: SPAIN, Canary Islands, La Gomera, S Hermigua , El Cedro: Mirador El Bailadero, Sonchus gomerensis , N28°07’22” W17°12’29”, 994 m, 9.10.2008, leg. Astrin & Stüben (“25”), coll. Stüben; 13, 1Ƥ: SPAIN, Canary Islands, La Gomera, Hermigua , Ibo Alfaro, leaf litter and plant remains of an Avocado plantation, N28°09’58” W17°12’11”, 255 m, 9.10.2008, leg. Astrin & Stüben (“23”), coll. Stüben; 1Ƥ: SPAIN, Canary Islands, La Gomera, S Hermigua , El Cedro, Sonchus hierrensis , N28°08’18” W17°12’52”, 791 m, 9.10.2008, leg. Astrin & Stüben (“26”), coll. Stüben.

Differential diagnosis. At its type locality near Hermigua on La Gomera, Calacalles hermigua sp. n. occurs syntopically with the new, slightly smaller species Calacalles nataliae (to which it is compared below). Calacalles hermigua from La Gomera has so far been considered conspecific to Calacalles seticollis (Wollaston, 1864) from El Hierro (type locality) by Bahr (2000), but our molecular analysis shows it as its sister species (cf. Fig. 1 ), with interspecific p -distances around 2%. More importantly, conspicuous morphological differences exist.

Calacalles hermigua is distinguished from Calacalles seticollis by:

1. The broader and shorter elytra, which are not clearly separated from the pronotum: these are 1.30x–1.47x as long as wide ( Fig. 3 ).

2. The even, slender intervals of the elytra are raised keel-like; elytral striae are broader than the small intervals.

3. The pronotum is stouter and – at the base – also broader than at the fore-margin ( Fig. 3 ).

Calacalles seticollis is distinguished from Calacalles hermigua by: 1*. The oblong-oval elytra, which are clearly separated from the pronotum; they are a least 1.60x as long as wide ( Fig. 2 ).

2*. All intervals of the elytra are in-plane; elytral striae are narrower than the intervals. 3*. The longer pronotum, which is laterally evenly rounded; base and fore-margin of the same breadth ( Fig. 2 ).

The aedeagi and the endophalli of these two species do not show significant differences in structure.

In order to molecularly differentiate C. hermigua from other species of Calacalles , we here present DNA barcodes (GenBank accession numbers GQ332315 , GQ332331 , GQ332318 , GQ332334 , cf. Table 1).

Description ( Fig. 3 ).

Length: 2.00– 2.60 mm (without rostrum).

Head: Rostrum broader towards the apex; male rostrum with a dense cover of scales that continues also anterior to the insertion of the antennae, 3x as long as wide, finely and spaciously punctuated; female rostrum slender, nearly 4x as long as wide, more brilliant, but points not as fine as in male; antenna with 7 antennomeres; eyes large.

Pronotum: 1.04x–1.09x as long as wide, widest behind the middle, at the end of the second fifth of the pronotum. At the sides oblong-ovally rounded, in front of fore-margin laterally narrowing in rectilinear way; pronotum stout, base broader than at fore-margin; disc of the pronotum slightly arched in front of the base; behind fore-margin flat; circular and saucer-shaped scales completely adherent. If the scale cover is complete, the dense and fine punctures are not visible under the scales; disc of the pronotum with dark brown scales in front of base, bright longitudinal fasciae or (very variable) beige-coloured/white spots at the sides and in front of the fore-margin. Fore-margin with corona of 14 to 16 light and dark, erect bristles; identical bristles isolated at the sides and also densely packed in the middle of the pronotum (forming a cross band of bristles).

Elytra: broad and short, 1.30x–1.47x as long as wide, in middle with sides parting towards the base oblong-ovally, towards the apex rounded egg-shaped; in lateral view contour-line of elytra flatter behind the base, elytral declivity more steeply sloped. With round, adherent, mostly brown scales which completely cover the slender intervals. Where the scale cover is missing, the very broad elytral striae are visible. Circular punctures of elytral striae very dense and striae clearly broader than intervals. Second, fourth and sixth intervals elevated and keel-like, uneven intervals impressed. Even elytral intervals and sutural interval with a single row of flattened, erect, slender bristles; bristles tapered and 4x–5x as long as wide on elytral declivity; bristles separated by about 2x bristle-length, more closely spaced on elytral declivity. Base of elytra concave, beyond this with bright, vague (poor in contrast) spots of scales. Lateral light longitudinal fasciae of pronotum continued as small spots on the fourth and fifth intervals beyond elytral base; scutellum with light scales.

Legs: Front femora long, reaching the fore margin of the eyes, hind femora reaching the fourth abdominal segment; covered with light, widely-spaced and clubbed bristles. Tarsi and apex of tibiae light brown.

Venter: First abdominal sternite at most as long as the three following sternites together. Second abdominal sternite as long as the very small sternites 3 and 4 together.

Female genitalia: See Figure 8 .

Aedeagus: Internal sac with structure resembling bulb peelings ( Fig. 6 ).

Ecology. The species was mainly collected south-east of Hermigua near Casas del Palmar from the lignified and partially dead stems of Sonchus hierrensis (Pit.) Boulos (family Asteraceae ) growing on a steep rocky slope. The individuals collected in the laurel forest (cf. 'further material' above) were found on the same plant or on Sonchus gomerensis Boulos. Two specimens were found in the leaf litter and plant remains of an Avocado plantation.) The C. hermigua specimens from the thermophilous shrub zone and the moist 'laurisilva' or laurel forest are genetically almost identical (0.4% divergence).

Distribution. This species is so far only known from the Canarian island of La Gomera.

Etymology. The species name refers to the type locality, which lies some kilometres south-east of Hermigua ; it is used as a noun in apposition.

Figures

FIGURE 1. Bayesian 50 % majority rule consensus using the 16 S and CO 1 genes. Numbers indicate nodal posterior probabilities. The scale shows the expected nucleotide substitutions per site and the bars next to the tree denote subfamily assignment. Taxonomic changes are indicated (new subgeneric placement only through subgenus bars).

FIGURES 2 – 4. Habitus (dorsal / lateral view) of the two new Calacalles species in comparison with Calacalles seticollis (Wollaston, 1864).

FIGURES 5 – 8. Male (aedeagus, ventral / lateral view, Figs. 5, 6) and female genitalia (Figs. 7, 8) of the two new Calacalles species.

FIGURES 9 – 26. Comparison of the endophalli of all known Calacalles species.