Corresponding author: Paolo Marcia (
Academic editor: Augusto Taglianti
The subtribe
Work with
Monophyly of
However, the monophyly of the Euro-Mediterranean core of
Newly designated Sardinian
Male genitalia were dissected, dehydrated in ethanol, cleared in cold KOH, examined and illustrated, using standard techniques before their definitive inclusion on microscope slides attached to the respective specimens. Line drawings were made using a camera lucida attached to stereomicroscopes Wild M-5, and a microscope Leitz Orthoplan.
Photographs of male genitalia were prepared by Paolo Magrini (Florence), with a Nikon D1 digital camera mounted on a Nikon Labophot II binocular microscope. P. Magrini also prepared distributional maps of
The median lobe of aedeagus is synonym of phallus of authors. The proximal gonocoxite 1, and the more distal gonocoxite 2 (in the sense of
Acronyms:
body Total length, from the anterior margin of clypeus to the apex of elytra, measured along the elytral suture.
overall body length, from apex of mandibles to apex of elytra, measured along the suture.
ratio length of Pronotum, as linear distance from the anterior to the posterior margin (peduncle included), measured along the midline to the maximum Width of Pronotum.
ratio length of Elytra, as linear distance from the basal ridge to the apex, measured along the elytral suture to the maximum Width of Elytra.
ratio maximum Width of Elytra to maximum Width of Pronotum
length of antenna.
Collections:
all type specimens are preserved in Casale Collection (University of Sassari, Italy)
Italy, Central-Eastern Sardinia: Dorgali (Nuoro province), Cala Gonone: Bue Marino cave
Holotype male with the following data: I – Sardegna, Dorgali (NU), Gr. Bue Marino 10.IX.2006 P. Marcia leg.; paratypes: female, same data as holotype; female: I – Sardegna, Urzulei (NU) Codula di Luna, Gr. Su Spiria 1988 Sa/NU 23.VII.1995 R. Loru leg. (CCa).
The Latin noun “
From
A medium-large sized
Body elongate, convex (
Head with ocular part of genae regularly convex, constricted toward the neck. Eyes absent. Supra-antennal plates separated from genae by deep and broad furrow; frontal furrows very deep, transversally wrinkled; vertex with an evident, convex tubercle in the middle; antennae moderately elongate (AL: 1.31 mm in male holotype), antennomeres 3–10 slightly longer than wide.
Pronotummoderately convex, elongate (PL/PW: 1.0), with its maximum width at the anterior third; sides moderately rounded, slightly attenuated in front, markedly constricted to the basal peduncle; anterior angles acutely prominent; median furrow narrow and deeply impressed; lateral furrows very narrow and superficial.
Elytraelongate
Male genitalia as in
Female genitalia (examined, not illustrated) without any peculiar characteristic: gonocoxites 2 rather short, regularly curved outwards, each with two moderately elongate, robust spiniform setae on the outer side, the distal of them being distinctly longer and thickener than the proximal one.
Two specimens of
In spite of many subsequent investigations in both these caves, including setting pitfall traps, no further individuals of this species have been obtained.
The following features of
Italy, Central-Eastern Sardinia: Oliena (Nuoro province), Corrasi Mt.: Nurra ‘e Pradu cave (speleological inventory number: 3083 Sa/NU), 1220 m a.s.l. ,
Holotype male with the following data: I – Sardegna, Oliena (NU), M. Corrasi 26.I.2008 P. Marcia”, “Gr. Nurra ‘e Pradu” (CCa).
The name derives from the Oliena village at the base of the Corrasi mountain in which this new species, and many other hypogean organisms were discovered. An ancient legend says that the inhabitants (
A large sized
Body elongate but robust, convex (
Integument shiny, highly polished; microsculpure with fine, hardly visible microlines in form of isodiametric mesh pattern on head and elytra, almost vanished on pronotum.
Head robust, with ocular part of genae markedly convex, constricted toward the neck. Eyes absent. Anterior angles of clypeus acutely prominent. Supra-antennal plates prominent laterally, with outer margin beaded, separated from genae by deep and broad furrow; frontal furrows very deep, with shallow wrinkles in the posterior tract; vertex with an evident, convex tubercle in the middle; antennae elongate (AL: 1.58 mm in male holotype) but robust, thickened; antennomeres 6–10 slightly longer than wide.
Pronotum markedly convex, relatively wide (PL/PW: 0.95), with its maximum width at the basal third; sides moderately rounded, slightly narrowed in front, markedly constricted to the basal peduncle; anterior angles acutely prominent; median furrow very shallow; lateral furrows very narrow and superficial.
Elytraelongate
Male genitalia as in
Female genitalia: unknown.
The new taxon appears related to
The following operative and provisional key is provided to distinguish the cave dweller (deep hypogean, or troglophilic)
1 | Larger in size (TL: mm 2.9–3.6; L: 3.0–4.0); elytra with intervals 2–7 all having setiferous punctures, and with lateral margins serrate from the humeral angle to apex. Deep hypogean species, known from caves only | 2 |
– | Smaller in size (TL less than 3 mm); elytra with only intervals 2–3-5–7 having setiferous punctures. Endogean but troglophilic species, occasionally found in caves | 6 |
2 | Larger in size (TL: 3.10–3.65; L: 3.40–4.05). Median lobe of aedeagus with apical lamina very elongate, spatulate or axe-shaped distally ( |
3 |
– | Smaller in size (TL: 2.90–3.10; L: 3.00–3.40). Median lobe of aedeagus (in the two species in which it is known) with apical lamina short, rounded or sub-truncate distally ( |
4 |
3 | Larger in size (TL: 3.64 mm; L: 4.05 mm, in male holotype). Median lobe of aedeagus larger, with apical lamina wider distally ( |
|
– | Smaller in size (TL: 3.10 – 3.65 mm; L: 3.40 – 3.86 mm). median lobe of aedeagus smaller, with apical lamina more elongate and narrower distally ( |
|
4 | Anterior angles of both clypeus and pronotum rounded, slighly prominent in front; genae slightly convex (Central Eastern Sardinia, Seui: Is Diavolus cave) | |
– | Anterior angles of both clypeus and pronotum very prominent in front; genae very convex, inflate | 5 |
5 | Elytra shorter, ovate, with lateral sides rounded and lateral margins with markedly prominent and numerous (23–25) teeth. Median lobe of aedeagus markedly curved, with apical lamina shorter and rounded distally ( |
|
– | Elytra elongate, sub-parallel sided; lateral margins with slightly prominent and less numerous (14–16) teeth. Median lobe of aedeagus slightly curved, with apical lamina more developed and sub-truncate distally ( |
|
6 | Larger in size (TL: 2.31–2.50; L: 2.58–2.99). Elytra with lateral margins serrate in the basal third only. Median lobe of aedeagus with apical lamina short; endophallus with copulatory piece in the shape of twisted lamina (Central Eastern Sardinia: Sadali, Is Janas cave; Nurallao [Nuoro]) | |
– | Smaller in size (TL: 1.99–2.22; L: 2.11–2.50). Elytra with lateral margins serrate from the humeral angle to apex. Median lobe of aedeagus with apical lamina markedly elongate and curved on the ventral side; endophallus with copulatory piece in the shape of triangular lamina, rounded distally and hollow at base. Central Eastern Sardinia, near Dorgali and Galtellì, in deep soil and caves |
As recently recalled (
Furthermore, these authors do not consider members of the subtribe
Two hypotheses have been proposed to explain the origin and the exceptional specific diversity of the genus
The first hypothesis proposes at least two different, heterochronic colonisation events. The older one is represented by the common ancestor of the subgenus
This scenario should be similar to the process recently proposed by
The second hypothesis proposes that all Sardinian
In other words, the question is: how many times have
The similarities between the male genitalia of some Sardinian species and those of species of the Apennine chain, the Elba island and Sicily, supports the hypothesis of multiple colonisations of the island by different ancestors. This is further strengthened by the remarkable absence of
World distribution of the subtribe
Adaptive radiation might work very rapidly. Classic examples include Hawaiian silverswords and
The genus
Recent research in the field shows a scenario in which two, three or more sympatric
A similar process – e.g. the colonization of Sardinia by a continental
Available data, and discoveries in progress (including two further species not yet described, but indicated in the map of
The speciation events that produced these taxa should have been originated by isolation of small populations in micro-geographic areas, in deep soils and caves, and an exceptional extent of adaptive colonisation and diversification into a variety of soil and underground compartments and ecological niches induced by the Plio-Pleistocene climatic changes, with some cases of subsequent overlap of distributions in wet, forested phases (
The hypothesis here proposed, that
We are particularly indebted to our good friend Paolo Magrini (Florence), for providing some of the illustrations to this paper, and for data, discussion, and pleasant days in the field in Sardinia. For the loan of material, the assistance both in the field and in laboratory, and information on which the present contribution is based, we thank all those who helped us in several years of study of the subterranean Sardinian fauna: in particular, concerning the present contribution, Giuseppe Grafitti, Enrico Lana, Roberto Loru, Alessandro Molinu, Carlo Onnis, Laura Sanna and Fabio Stoch. A great acknowledgement is due to Vasily Grebennikov (Ottawa), for suggestions, corrections and improvements to the original manuscript. We thank also Stefano Birindelli for identification of terrestrial snails.
Research was in part supported by grants INTERREG 3 (Sardinia-Corsica-Tuscany), PRIN projects of the Italian Ministry of the University and Scientific Research (“Zoogeography of Mediterranean - Southern African disjoint distributions by a multimethod approach” and “The endemism in Italy”). P. Marcia has received support from Regione Sardegna through a grant co-financed with funding from the PO Sardegna FSE 2007–201 L.R.7/2007 “Promozione della ricerca scientifica e dell’innovazione tecnologica in Sardegna”.