Madeiracalles, 2010

Stüben, Peter E. & Astrin, Jonas J., 2010, Molecular phylogeny in endemic weevils: revision of the genera of Macaronesian Cryptorhynchinae (Coleoptera: Curculionidae), Zoological Journal of the Linnean Society 160 (1), pp. 40-87 : 72-75

MADEIRACALLES STÜBEN & ASTRIN GEN. NOV.

( FIGS 14A–E , 25–32 , 34 )

Type species: Acalles dispar Wollaston, 1854

Wollaston, 1854, 1857, 1865; Lundblad, 1958; Stüben, 2002b; Stüben et al., 2003; Stüben & Astrin, 2009 in press.

Compilation of the species of the genus

Madeiracalles

Madeiracalles achadagrandensis (Stüben, 2002) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles albolineatus ( Wollaston, 1854) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles cinereus (Wollaston, 1860) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles coarctatus ( Wollaston, 1857) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles dispar ( Wollaston, 1854) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles festivus ( Wollaston, 1857) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles histrionicus ( Wollaston, 1857) comb. nov. (formerly: Acalles ) – Porto Santo

Madeiracalles machadoi ( Stüben, 2006) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles nodiferus ( Wollaston, 1854) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles portosantoensis (Stüben, 2002) comb. nov. (formerly: Acalles ) – Porto Santo

Madeiracalles pulverosus (Gemminger, 1871) (nec. Acalles pulverulentus Wollaston, 1854 ) comb. nov. (formerly: Acalles ) – Madeira

= Acalles oblitus Wollaston (1854) syn. ( Stüben & Astrin, 2009 , in press)

Madeiracalles saxicola ( Wollaston, 1854) comb. nov. (formerly: Acalles ) – Deserta Grande (including type locality), Madeira

Madeiracalles terminalis ( Wollaston, 1854) comb. nov. (formerly: Acalles ) – Madeira

= Acalles terminalis var. b Wollaston (1854) syn. (Stüben, 2002)

Madeiracalles tolpis (Stüben, 2002) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles tristaensis (Stüben, 2002) comb. nov. (formerly: Acalles ) – Madeira

Madeiracalles vau ( Wollaston, 1854) comb. nov. (formerly: Acalles ) – Madeira

Description

Size: 2.5 ( M. tolpis )– 7.2 mm ( M. nodiferus )

Head: Eyes circular; the reddish-brown rostrum of the ♂ with dense and oval punctures, the basal third covered with brown scales; length: approximately two-thirds of length of pronotum. The rostrum of the ♀ more slender, conspicuously longer (four-fifths of length of pronotum), with finer and less dense punctures and basal third only spaciously covered with scales.

Pronotum: 1.04–1.14¥ (-1.22¥ M. tristaensis ) as long as wide; widest in the middle; outline rounded evenly oval or ‘bellied’ (as in robust specimens of M. pulverosus ). Disc of pronotum with aggregations of dark brown bristles sticking out vertically on both sides of the often only fine mid groove or shallow middepression.

Elytra: Elongated, ‘canoe-like’: 1.27–1.51¥ (1.53–1.68¥ M. tristaensis ) as long as wide; widest directly in front of the middle (or at the end of the basal third); elytra, often rounded elliptically, the anterior sixth part steeply sloped towards the base of elytra; towards the apex beginning with a lateral depression (somewhat concave on the flanks), the apex itself elongated ‘beak-like’. The integument is very variable. Between a more or less unicoloured dark brown and a light brown or beige basic colouring there are all imaginable changes and crossovers, although always with a light, v-shaped fascia on the elytral slope and often with a diffuse pale-white scutellar mark at the base. Moreover, most of the species have a light falciform fascia extending from the sixth interval at the base to the scutellar stripe in the middle of the elytra. Elytra with numerous protuberances covered with bristles, the biggest, often elongated and high-piled aggregations of bristles are situated on the second interval of the elytral slope.

Legs: Long; front femur reaching posterior margin of eye; tibia with short, often ‘erinaceous’ distant bristles; femur with sloping, raised bristles; tibia annulated with belts of dark brown to black scales.

Venter: Second abdominal sternite as long as sternites 3 and 4 combined.

Aedeagus: Median lobe always with very long capillary bristles ( Figs 25–27 ); endophallus very small and ‘complex’, besides the inverse v-shaped basic structure there is (except for three minor variances) a clearly cognizable basic pattern ( Figs 28–32 ).

Differential diagnosis and discussion: According to the structure of the internal sac there are only subtle differences amongst most Madeiracalles species ( Figs 28–32 ); the interspecific variability is much higher in the Canarian clade. As a result of this, splitting up the morphologically very ‘homogeneous’ genus Madeiracalles into subgenera does not make sense, especially when striving for comparability/ equivalence of supraspecific taxa in all Macaronesian Cryptorhynchinae . See also the ‘Key to the genera and subgenera of Macaronesian Cryptorhynchinae’.

The species of Madeiracalles represent a monophyletic group forming the so-called ‘Madeiran clade’ (cf. Fig. 1A ). This group is distinguished from the Canarian genera by (1) the conspicuously long and slender, capillary bristles on the median lobe of the aedeagus ( Figs 25–27 ); and (2) the ‘complex’ inverse v-shaped structure of the endophallus, which shows a clearly comprehensible basic pattern and is doubtlessly homologous amongst the species of Madeiracalles ( Figs 28–32 ).

Biology and ecology: On the Canary Islands, instances of radiative cospeciation of some Cryptorhynchinae with their host plants (of the genera Aeonium , Sonchus , and Tolpis ) have been ascertained ( Sprick & Stüben, 2000; Stüben, 2000c). However, on Madeira there is no evidence for such an evolution. No Madeiran cryptorhynchine species is known to develop on Aeonium and Sonchus . Madeiracalles pulverosus lives on Tolpis succulenta (the name seems to suggest it, but Madeiracalles tolpis does not belong in this rootdrilling group, even though it develops in thin twigs of Tolpis succulenta ). Madeiracalles pulverosus shows the same larval development and breeding behaviour as Sonchiacalles muelleri of the Canary Islands. The larvae and pupae of M. pulverosus behave in the same way in the chambers (made of latex and agglutinated small stones) at the root neck of Tolpis succulenta ( Stüben, 2002b) as those of Sonchiacalles muelleri , e.g. on Tolpis calderae (La Palma) or Tolpis proustii (El Hierro) ( Stüben, 2000a, 2008a) ( Figs 33, 34 ). Nevertheless, the dendrogram shows that the two species are not directly related (cf. Fig. 1A ), which takes us to the conclusion that this seemingly complex behavioural pattern has obviously evolved in parallel.

We suggest that in the colonization of Porto Santo (and later of Madeira), the same evolutive pattern took effect as on the Canary Islands. In addition, in this archipelago, the pioneer species were those xerothermophilic ones preferring the coastal succulent belt, e.g. the ancestor of the extremely xerothermophilic Madeiracalles portosantoensis (from the Pico do Castelo on Porto Santo) or the succulicole, coastal M. pulverosus that develops in the root neck of Tolpis succulenta on the sun-exposed rocks of Madeira during summer. The colonization of the shady and moist laurel forests of Madeira obviously started much later (even if according to the phylogenetic analysis the extremely xerothermophilic Madeiracalles saxicola , which develops in Euphorbia piscatoria and has been described from the arid island Deserta Grande, does not fully fit in; cf. Fig. 1A ). Today most of the Cryptorhynchinae of Madeira are highly adapted to the laurel forest, e.g. Madeiracalles cinereus ( Fig. 14A ) that lives in the trade wind zone of the moist laurel forest and develops in thin twigs of a dendriform species of Euphorbiaceae , Euphorbia mellifera ( Stüben, 2002b; Stüben & Astrin, 2009 in press) ( Fig. 14C ).

Etymology: The name Madeiracalles refers to the Madeiran clade as recovered in our analysis for the monophyletic group of former Acalles s.l. species from the archipelago of Madeira.

Distribution: Endemic to the archipelago of Madeira.

CALACALLES PEYERIMHOFF, 1925

( FIGS 15A–E, 16A–E )

Type species: Acalles (Calacalles) theryi de Peyerimhoff, 1925 – Morocco (including type locality) , Portugal

Wollaston, 1864; de Peyerimhoff, 1925; Uyttenboogaart, 1939; Roudier, 1954; Bahr, 2000; Behne, 2000; Stüben et al., 2001; Stüben, 2002b, 2003b, 2004b, c, 2005b; Germann & Stüben, 2006; Astrin & Stüben, 2008.

Compilation of the subgenera and species of the genus Calacalles of the Macaronesian Islands

Calacalles s.s.

Calacalles affinis Bahr, 2000 – Tenerife

Calacalles atomarius Bahr, 2000 – Tenerife

Calacalles exiguus Bahr, 2000 – Tenerife (including type locality), La Palma

Calacalles fuerteventurensis Bahr, 2000 – Fuerteventura (including type locality), Lanzarote

Calacalles minutus Bahr, 2000 – La Gomera (including type locality), Tenerife

Calacalles pumilio Bahr, 2000 – Tenerife (including type locality), La Gomera

Calacalles pusillus Bahr, 2000 – Tenerife (including type locality), La Gomera, Gran Canaria

Calacalles seticollis Wollaston, 1864 – El Hierro (including type locality), La Palma, Tenerife, La Gomera

= Acalles wollastoni palmensis Roudier, 1954 syn. Bahr, 2000: 121

= Acalles zumpti Uyttenboogaart, 1939 syn. Bahr, 2000: 122

Calacalles subcarinatus (Israelson, 1984) – Azores : Flores (including type locality), Faial, São. Jorge, Terceira, Pico, São. Miguel, Santa Maria

Calacalles wollastoni (Chevrolat, 1852) – Madeira (including type locality), Porto Santo

= Acalles cylindricollis Wollaston, 1964 syn. Wollaston, 1865: 280

Crateracalles Stüben, 2004 subgen.

Type species: Acalles droueti Crotch, 1867

Calacalles (Crateracalles) droueti (Crotch, 1867) – Azores: Flores (including type locality), Faial, Pico

Calacalles (Crateracalles) azoricus (Stüben, 2004) – Azores: Faial (including type locality)

Discussion: The genus Calacalles was revised several years ago for the species of the Canary Islands ( Bahr, 2000). Stüben (2004b) added the subgenus Crateracalles from the Azores. The transfer from Acalles to Calacalles was mainly motivated (1) by the extraordinary size (the specimens of this subgenus are three times longer than the specimens of Calacalles s.s.); (2) by the characteristics of the elytra (with strong bristle-tufts) and pronotum (with a saucer-shaped rim of thorns); and (3) by their different host plant interactions. Although these criteria all left some uncertainty regarding the transfer, only the similar ‘shellshaped’ structures of the internal sac of the aedeagus retain some morphological significance for the inclusion in Calacalles (cf. Figs 15B, 16B ).

The molecular analysis of the set of available species confirms (maximal support value) the genus Calacalles as a natural group. Even the noticeably large species C. droueti and C. azoricus of the islands Faial, Pico, and Flores are now corroborated as part of the genus. The reconstruction shows that the subgenus Calacalles s.s. is paraphyletic with regard to the subgenus Crateracalles (cf. Fig. 1A ).

However, there remain numerous questions and issues. It is doubtful whether – after investigating further Canarian samples – the hypothesis of Bahr (2000), who proposed a ‘multi-insular’ distribution for several Calacalles species , will hold. The claim of synonymy for Calacalles wollastoni palmensis ( Roudier, 1954) is questionable, as is the usefulness of some exoskeletal characters that provide only scarce criteria for a convincing species discrimination (e.g. antennae with six or seven antennomeres, respectively; or elytra projecting above the pronotum).

According to our molecular analysis, the Macaronesian Calacalles s.s., which are amongst the smallest Cryptorhynchinae (cf. Fig. 15A ; body lengths of 1.5– 2.5 mm), are derived from an ancestor species of those Calacalles living in North Africa and on the Iberian Peninsula as well as on the adjoining islands. Calacalles moraguesi (Desbrochers, 1898) of Mallorca and Menorca (analysed in this study) is closely related to Calacalles theryi ( de Peyerimhoff, 1925) of the Atlantic coastal belt of Portugal and Morocco.

Preliminary studies towards a revision of the genus Calacalles are currently being undertaken (J. J. Astrin & P. E. Stüben, unpubl. data).

Differential diagnosis: Distinguishing Calacalles from the other genera of Macaronesian Cryptorhynchinae is not difficult and can be carried out quickly with the ‘Key to the genera and subgenera of Macaronesian Cryptorhynchinae’ (see below).

Distribution: Macaronesian Islands (except Selvagens), Iberian Peninsula (including Balearic Islands), North Africa.

Figures

Figure 1. A, Bayesian 50% majority rule consensus for the two analysed mitochondrial genes. Numbers indicate nodal posterior probabilities. The scale shows the expected nucleotide substitutions per site. Abbreviations in parentheses denote subgenus (see text). Genus names in bold indicate new nomenclature. Circles mark colonization events (in black: invasive species). For many Macaronesian species, the respective host plants are depicted. The second page of the tree shows the taxa corresponding to the ‘Atlantic clade’. B, chronogram based on relaxed phylogenetic analysis of the two mitochondrial genes, using the uncorrelated lognormal model of substitution rate variation. Numbers next to the nodes indicate mean divergence times (in Myr), with 95% confidence intervals of divergence times depicted as bars at the corresponding nodes. N.B. Although the underlying topology is that delivered by MrBayes, BEAST does not allow polytomies, which it resolves arbitrarily.

Figures 2–22. Morphological, biological, and ecological comparison of the genera and subgenera of Macaronesian Cryptorhynchinae along with the respective sections of the tree; (TS) = type species. Figures 4E and 5E show a section of the tree that results when 16S sequences for Aeoniacalles aeonisimilis* and Dendroacalles euphorbiacus* are excluded.

Figures 25–32. 25–27, Madeiracalles is distinguished from the Canarian genera by the conspicuously long and slender, capillary bristles on the median lobe of the aedeagus. 28–32, the ‘complex’ inverse v-shaped structure of the endophallus shows a clearly comprehensible basic pattern and is doubtlessly homologous amongst the species of Madeiracalles.

Figures 33–34. Sonchiacalles muelleri has the same larval development, the adults show identical breeding behaviour and the larvae and pupae behave in the same way in the chambers (made of latex and agglutinated small stones) at the root neck of, e.g. Tolpis proustii on El Hierro as Madeiracalles pulverosus in the roots of Tolpis succulenta on Madeira.