Pholcus alticeps Spassky, 1932 [třesavka vysokohlavá]

Pavoukovci České republiky; Záhadná firemní skálovka; Vzácné druhy listovníků v Miloticích; Nález snovačky Enoplognatha mordax (Theridiidae) v Podkrušnohoří a plachetnatky Porrhomma campbelli (Linyphiidae) v Krušných horách; Výskyt skákavky  Philaeus chrysops (Salticidae) mimo přírodní stanoviště; Pár poznatků o výskytu a biologii snovačky Dipoena torva v Železných horách; Meta menardi neboli křižák temnostní: experimentální vhled do ekologické tolerance pavouka temnot; Štíři jako hostitelé larev roztočů; Výskyt pavouků v zimním období, včetně skákavky Sibianor larae (Salticidae) a třesavky Pholcus alticeps (Pholcidae); Vzpomínka na Rudu Macka; Pavouci ve školce vítáni; Zoologické dny Brno 2025; Arachnologická exkurze 2025 – Pobečví; Česká bibliografie; Inventarizační průzkumy 2024; Pokyny pro autory

Pavouci České republiky; Taxonomické změny; Víme, koho máme ve znaku ČASu?; Panamomops szinetari (Araneae: Linyphiidae), nový druh pro Česko a Slovensko; panonský stepní relikt, expandující teplomilný prvek, nebo zavlečený invazivní druh?; Významné faunistické nálezy pavouků na mokřadech Jižní Moravy; Přehlížená domácí plachetnatka; Pholcus alticeps Spassky, 1932 v Krušných horách. Po druhé…; Výskyt pavučenky Erigone dentosa (Araneae: Linyphiidae) v Krušných horách; Nová lokalita sekáče Nemastoma bidentatum sparsum (Opiliones: Nemastomatidae) v ČR; Zajímavé nálezy sekáčů aneb jak občanská věda pomáhá našim opilionologům, část druhá; Čekání na odlet; European Congress of Arachnology – Zadar 2025; Novodobé určovací semináře; Česká bibliografie; Nové knihy

Haplogyne araneomorphs are a diverse spider clade. Their karyotypes are usually predominated by biarmed (i.e., metacentric and submetacentric) chromosomes and have a specific sex chromosome system, X1X2Y. These features are probably ancestral for haplogynes. Nucleolus organizer regions (NORs) spread frequently from autosomes to sex chromosomes in these spiders. This study focuses on pholcids (Pholcidae), a highly diverse haplogyne family. Despite considerable recent progress in pholcid cytogenetics, knowledge on many clades remains insufficient including the most species-rich pholcid genus, Pholcus Walckenaer, 1805. To characterize the karyotype differentiation of Pholcus in Europe, we compared karyotypes, sex chromosomes, NORs, and male meiosis of seven species [Pholcus alticeps Spassky, 1932; P. creticus Senglet, 1971; P. dentatus Wunderlich, 1995; P. fuerteventurensis Wunderlich, 1992; Pholcus phalangioides (Fuesslin, 1775); Pholcus opilionoides (Schrank, 1781); P. silvai Wunderlich, 1995] representing the dominant species groups in this region. The species studied show several features ancestral for Pholcus, namely the 2n♂ = 25, the X1X2Y system, and a karyotype predominated by biarmed chromosomes. Most taxa have a large acrocentric NOR-bearing pair, which evolved from a biarmed pair by a pericentric inversion. In some lineages, the acrocentric pair reverted to biarmed. Closely related species often differ in the morphology of some chromosome pairs, probably resulting from pericentric inversions and/or translocations. Such rearrangements have been implicated in the formation of reproductive barriers. While the X1 and Y chromosomes retain their ancestral metacentric morphology, the X2 chromosome shows a derived (acrocentric or subtelocentric) morphology. Pairing of this element is usually modified during male meiosis. NOR patterns are very diverse. The ancestral karyotype of Pholcus contained five or six terminal NORs including three X chromosome-linked loci. The number of NORs has been frequently reduced during evolution. In the Macaronesian clade, there is only a single NOR-bearing pair. Sex chromosome-linked NORs are lost in Madeiran species and in P. creticus. Our study revealed two cytotypes in the synanthropic species Pholcus phalangioides (Madeiran and Czech), which differ by their NOR pattern and chromosome morphology. In the Czech cytotype, the large acrocentric pair was transformed into a biarmed pair by pericentric inversion.