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Povzetek: The blue shark, Prionace glauca, is widely distributed in the Mediterranean and the Atlantic Ocean. The present study proposes a management plan for this species based on biological data, including length-weight relationships and other growth parameters, morphometry, and longevity. Regular biological sampling of the blue shark was carried out during a period of 24 months (October 2017–October 2019). Specimens were collected from the artisanal fishing boats operating off the Central Atlantic coast of Morocco, especially in the region of Sidi Ifni, and in seasonal acoustic surveys. A total of 7224 individuals were examined, including 3704 females and 3520 males. The total length (TL) ranged from 48 cm to 340 cm in females and 55 cm to 350 cm in males. Both sexes had a length-weight relationship of W(t) =10-6 * TL3.4283, indicating significant major allometry. The von Bertalanffy parameters for both sexes combined were L∞ = 413.59 cm, k = 0.20 year-1, and t0 = 0.76. Longevity (tmax) was more than 17 years for males and females.
Ključne besede: Prionace glauca, morphometry, length-weight, Von Bertalanffy parameters, longevity
Objavljeno v DiRROS: 31.07.2026; Ogledov: 255; Prenosov: 135
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Povzetek: The Siberian moth, Dendrolimus sibiricus Tschetverikov, is one of the most destructive conifer pests in Northern Asia, causing severe ecological and economic losses. In Russia, its range overlaps with that of the closely related pine-tree lappet Dendrolimus pini (L.), and this raises the potential for hybridization and complicates accurate identification, particularly in the context of the potential westward expansion of D. sibiricus. Here, we present the first comprehensive morphometric analysis of male genitalia aimed at distinguishing these two major forest pests and their hybrids. The study was based on D. sibiricus and D. pini specimens collected during the last 130 years (1894–2024) across Europe and Asia, including their hybrids reared indoors by crossing D. pini females with D. sibiricus males in 1956 and preserved in the collection of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg, Russia). Overall, 70 permanent genitalia slides were prepared (33 D. sibiricus, 33 D. pini, and 4 hybrids), and the following genital structures were measured: valva and harpe length, aedeagus width and length, and cornuti length. Dendrolimus sibiricus had significantly larger genital structures compared to D. pini: 74% longer harpe, 32% longer valva, and a 28% wider and longer aedeagus. In contrast, in D. sibiricus cornuti were 21% shorter than in D. pini. Hybrids displayed intermediate values for valva, harpe, and aedeagus lengths, and for these parameters, they significantly differed from both parental species. The following diagnostic indices were suggested to distinguish between the two species and their hybrids: Harpe Length/Valva Length Index (HL/VL) and Cornuti Length/Aedeagus Length Index (CL/AL). Decision-tree analysis identified HL/VL as the strongest predictor for separating the parental species and the Combined Genital Proportion Index (CGPI), which integrates harpe, valva, aedeagus, and cornuti lengths, as the strongest predictor for identifying hybrids. The morphometric criteria developed here have practical applications for monitoring programs and quarantine diagnostics, particularly in sympatric zones and regions at risk of D. sibiricus expansion.
Ključne besede: Siberian moth, pine-tree lappet, hybridization, genital morphometry, genitalia indices, species identification, quarantine diagnostics
Objavljeno v DiRROS: 09.06.2026; Ogledov: 334; Prenosov: 230
Celotno besedilo (3,67 MB)
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Povzetek: Polyploidy is an important evolutionary mechanism in flowering plants that can strongly affect their morphological and distributional traits. In this study, we investigated the differences in these traits among di-, tri-, and tetraploid populations of sweet spurge (Euphorbia dulcis), a common understory species in deciduous and mixed forests across Europe. We inferred the ploidy of 188 populations of E. dulcis by estimating relative genome size and chromosome counting. The data indicate that tri- and tetraploids are more widespread compared to the ancestral diploid populations, which are restricted to Liguria (north-western Italy) and adjacent regions. We suggest that polyploidisation was crucial for range expansion and the colonisation of higher latitudes, but not for the colonisation of higher elevations, where diploids appear to be more successful. Similarly, morphological differentiation after polyploidisation is only partly consistent with the classical hypothesis that polyploids are larger and have larger organs. Using nuclear ITS and plastid ndhF–trnL sequences, we inferred the spatio-temporal diversification of E. dulcis. It diverged from its diploid sister species E. duvalii, an endemic of southwestern France and adjacent Spain, in the mid-Pliocene. This divergence was likely due to vicariant speciation accompanied by adaptation to forest and grassland environments in E. dulcis and E. duvallii, respectively. Whereas the diploid populations of both taxa have restricted ranges today, polyploidisation within E. dulcis likely triggered by the Pleistocene climatic oscillations contributed to its significant range expansion and diversification. The species exhibits the highest genetic diversity in the south-western Alps, where all three ploidies co-occur. Based on the ploidy differentiation and the less pronounced genetic and morphological differentiation, we propose treating di- and triploids as well as two geographically and genetically divergent groups of tetraploids (eastern and western) as four subspecies. This challenges various taxonomic treatments previously proposed for this species. Our study highlights the importance of polyploidisation for diversification and range expansion, and indicates the necessity of further research to test hypotheses related to the morphological and distributional characteristics of polyploid organisms.
Ključne besede: forest understory species, morphometry, phylogeography, polyploidisation, taxonomy
Objavljeno v DiRROS: 18.04.2025; Ogledov: 983; Prenosov: 695
Celotno besedilo (6,03 MB)
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Povzetek: Natural hybridization of plants can result in many outcomes with several evolutionary consequences, such as hybrid speciation and introgression. Natural hybrid zones can arise as a result of fluctuating climate during the exchange of glacial and interglacial periods, where species retract and expand their territories, resulting in secondary contacts. On mountain ranges, such as the European Alps, hybrid zones of alpine species are frequently formed where different lineages meet. Willows are a large genus of woody plants with an immense capability of interspecific crossing. About 33 species of this genus inhabit the Alps, where intermediate phenotypes were frequently observed and proclaimed as hybrids, but rarely examined in detail. One of the reasons was a lack of informative molecular markers and suitable analytical tools to analyse this highly diverse and convergent genus. With the development of the RAD-seq technology, several questions regarding willow phylogeny and hybridization could be answered. In this study, a putative hybrid zone of two sister species, S. foetida and S. waldsteiniana, was investigated to study the genomic structure of populations within and outside their contact zone, to find evidence for hybrid speciation or introgression, and to analyse if morphological phenotypes are reflected by their genotypes. Individuals of the two species were sampled across their distribution range in the Alps and examined with the use of RADseq data and morphometric analyses. The results showed that a hybrid zone between the two species was established within the range of their contact zone. Patterns of genetic admixture in homoploid hybrids indicated introgression with asymmetric backcrossing to one of the parental species. Morphometric characteristics of hybrids supported the molecular data and showed intermediacy with a bias towards S. waldsteiniana. Only one potentially divergent hybrid lineage was observed, hinting to a possibility of localised hybrid speciation events.
Ključne besede: alpine plants, hybridization, morphometry, RAD sequencing, master thesis
Objavljeno v DiRROS: 17.01.2025; Ogledov: 1273; Prenosov: 483
Celotno besedilo (4,66 MB)