Evidence for reticulate palaeogeography: beetle diversity linked to connection‐disjunction cycles of the Gibraltar strait

Abstract

Aim Dispersal barriers between areas within some regions have appeared and disappeared throughout evolutionary time. Here we describe the distributional patterns displayed by three taxa living in such kind of regions. These patterns can be better explained considering a reticulated rather than a hierarchically branched palaeogeography. Location Western Mediterranean. Methods The taxa studied are Misolampus (Coleoptera, Tenebrionidae), Tentyria (Coleoptera, Tenebrionidae) and Thorectes (Coleoptera, Geotrupidae). All them are flightless and show a high degree of endemicity. The individual pattern of area relationships was determined separately for each genus by Brooks Parsimony Analysis (BPA). A theoretical general area cladogram was constructed based on the palaeogeographical history of the region. Finally, the general area cladogram is reconciled with the individual ones. Results The ancestor of Misolampus probably was North African. Land dispersal toward the Iberian Peninsula is proposed. Speciation within Iberia is related to specific vicariance events, and the presence of insular (Balearic Islands) populations is explained by sea‐surface or, more probably, human‐mediated dispersal. The ancestor of Tentyria was Iberic. The proposed hypothesis to explain the current species distribution mainly relies on the occurrence of specific vicariance events. However, the occurrence of some sea‐surface dispersal event is not discarded. Almost all possible vicariance events can be recognized in the first clade of the Thorectes genus. There is evidence for dispersal between Africa and Europe at different dates and in both directions. In spite of some uncertainties, the appearance of the second Thorectes clade can also be explained by the occurrence of specific historical events. An ancient dispersal toward the eastern Mediterranean and several dispersal events during the Messinian seem likely. Main conclusions The same historical events have specific outcomes in every tree (even in every branch within a tree) depending on the ability for dispersal and speciation of each taxon. Connection‐disjunction cycles of dispersal barriers have acted as diversity producers.

Biogeographical connections between the Maghreb and the Mediterranean peninsulas of southern Europe

“…Therefore, the Strait of Gibraltar should act much less as a biogeographical barrier than the Strait of Sicily. Consequently, the biogeographical connectivity over the Strait of Gibraltar is supported by genetic analyses (Cosson et al, 2005), but more studies emphasize the biogeographical split between the Maghreb and Iberia (Beerli, Hotz & Uzzell, 1996;De Jong, 1998;Castella et al, 2000;Palmer & Cambefort, 2000;Harris & Sá-Sousa, 2002;Gantenbein & Largiadèr, 2003); this is also underlined in many Mediterranean species only occurring on one side of this sea strait, as, for example, in lepidopterans (only Iberia: Leptidea sinapis, Satyrium spini, Polyommatus bellargus, Melitaea parthenoides, Hipparchia semele, Aulocera circe; only Maghreb: Tomares mauretanicus, Taurucus rosaceus, Polyommatus punctifera, Hipparchia hansii, Coenonympha arcanioides, Thymelicus hamza; Tolman & Lewington, 1997, García-Barros et al, 2004Tarrier & Delacre, 2008).…”

Molecular systematics and time-scale for the evolution of Timarcha, a leaf-beetle genus with a disjunct Holarctic distribution

“…The so-called Messinian crisis, a desiccation of the Mediterranean about 6 Mya caused by negative hydric balance, resulted in another sudden change in the configuration of the sea basin, with several emerged lands connected by land bridges offering opportunity for dispersal, e.g., North Africa-Iberia, Balearic Islands, Corsica-Sardinia (Palmer and Cambefort, 2000). The restoration of the sea level after the opening of the Gibraltar Strait at the end of the Messinian (5.3 Mya) would create new conditions for vicariance and allopatric speciation (Palmer and Cambefort, 2000, and references therein).…”

“…; (iii) $16 Mya extensive areas of inland saline lakes in northeast Iberia created a barrier between the southwest of the Peninsula and the northeast, which remained associated to Europe [vicariance of the western and eastern T. goettingensis complex lineages; G omez-Zurita et al, 2000c] (Altaba, 1997); (iv) 17-13 Mya (average $15 Mya), restoration of marine conditions between Tethys and Paratethys isolate East Asia Minor from the western Asia Minor and the Balkans [vicariance HUMM/METx] (Oosterbroek and Arntzen, 1992); and (v) 5.3 Mya the end of the Messinian era interrupts land connections formed after desiccation of the Mediterranean [Gibraltar Strait vicariances COAR/RIFF and RUGd/ESPA, Gymnesic break BALa/BALe, and isolation of Corsica CORN/ GOET](Palmer and Cambefort, 2000).…”

Mitochondrial markers reveal deep population subdivision in the European protected spider Macrothele calpeiana (Walckenaer, 1805) (Araneae, Hexathelidae)

“…However, throughout the complex and highly dynamic geological history of the Western Mediterranean, Iberia has been reconnected to Africa at least two more times. About 15 Ma, the collision between an arch moving west-caused by compression movements in a NE-SW line between present day southern France and North Africa-and the Gibraltar area produced the land connection between North Africa and Iberia (Palmer and Cambefort 2000). In the Late Miocene (~8 Ma) the formation of the Betic and Rifean marine passages in southern Spain and northern Morocco again divided the two continents (Duggen et al 2003).…”