https://www.um.edu.mt/library/oar/handle/123456789/144723 Sat, 11 Apr 2026 09:56:05 GMT 2026-04-11T09:56:05Z https://www.um.edu.mt/library/oar/handle/123456789/144737 Title: Integrative morphology and biogeography reveal cryptic diversity in Muticaria from central and southeastern Sicily : a multivariate approach to species delimitation with the description of 60 new taxa (Mollusca : Gastropoda : Clausiliidae) Authors: De Mattia, Willy; Reitano, Agatino Abstract: The genus Muticaria Lindholm, 1925 represents one of the most taxonomically complex radiations of Mediterranean clausiliids, characterized by extreme micro-allopatry, strong shell homoplasy, and limited dispersal ability. Traditional shell-based taxonomy has proven inadequate for resolving species boundaries within this genus, often leading to artificial lumping or unstable classifications. In this study, we present a comprehensive morphological revision of Muticaria from central and southeastern Sicily, integrating detailed genital anatomy with quantitative morphometrics and explicit geographic constraints. A total of 228 dissected specimens from 75 populations were analysed using a size-free multivariate framework based primarily on genital characters. Morphological distances (Mahalanobis Distance) were combined with geographic proximity thresholds and no-chain constraints within a STRICT species-delimitation algorithm designed to reflect biologically realistic micro-allopatric diversification. Hierarchical clustering, principal component analyses, and discriminant analyses consistently recovered a structured pattern of differentiation, revealing 33 well-defined species-level entities. Of these, 28 are described here as new to science (60 taxa including species and subspecies), while five correspond to previously recognized taxa used as taxonomic anchors. Shell morphology, although extensively documented, proved highly homoplastic and insufficient for species delimitation when analysed independently, but remains informative for documenting intraspecific and subspecific variation once species boundaries are defined anatomically and geographically. Unconstrained clustering based on morphology alone produces biologically implausible groupings, highlighting the necessity of integrating spatial structure into taxonomic decision-making. Our results demonstrate that genital morphology, evaluated within an explicit morpho-geographic framework, provides a robust and reproducible basis for species delimitation in non-adaptive radiations of low-dispersal land snails. The approach adopted here offers a generalizable model for resolving taxonomic complexity in other morphologically conservative and geographically fragmented systems.; [Integrazzjoni ta’ morfoloġija u bijoġeografija tiżvela diversità kriptika f'Muticaria miċ-ċentru u x-xlokk ta' Sqallija: approċċ multivarjat għad-delimitazzjoni tal-ispeċi bid-deskrizzjoni ta’ 60 tasson ġdid (Mollusca: Gastropoda: Clausiliidae).] Il-ġeneru Muticaria Lindholm, 1925 jirrappreżenta waħda mill-aktar radjazzjonijiet tassonomikament kumplessi tal-klawsiljidi tal-Mediterran, ikkaratterizzata minn mikro-allopatrija estrema, qxur b’omoplażija qawwija, u kapaċità għat-tixrid limitata. It-tassonomija tradizzjonali bbażata fuq ilqoxra mhijiex biżżejjed biex jiġu solvuti l-konfini tal-ispeċi f'dan il-ġeneru, u ħafna drabi twassal għal raggruppamenti artifiċjali jew klassifikazzjonijiet instabbli. F'dan l-istudju qegħdin nippreżentaw reviżjoni morfoloġika komprensiva tal-Muticaria minn Sqallija ċentrali u tax-xlokk, bl-integrazzjoni ta’ anatomija ġenitali dettaljata flimkien ma' morfometrija kwantitattiva u limiti ġeografiċi espliċiti. Total ta’ 228 kampjun dissezzjonat, minn 75 popolazzjoni, ġie analizzat permezz ta’ qafas multivarjat (mingħajr id-daqs) ibbażat primarjament fuq il-karattri ġenitali. Id-distanzi morfoloġiċi (distanza ta’ Mahalanobis) ġew ikkombinati ma' limiti ta’ prossimità ġeografika u restrizzjonijiet mingħajr katina fi ħdan algoritmu STRICT ta' delimitazzjoni tal-ispeċi, iddisinjat biex jirrifletti diversifikazzjoni mikro-allopatrika bijoloġikament realistika. Raggruppament ġerarkiku, analiżi tal-komponenti prinċipali, u analiżi diskriminanti rkupraw b’mod konsistenti mudell strutturat ta’ differenzjazzjoni, u żvelaw 33 entità fil-livell ta’ speċi b’definizzjoni tajba. Minn dawn, 28 huma deskritti hawn bħala ġodda għax-xjenza (60 tasson, inklużi speċi u sottospeċi), filwaqt li ħamsa jikkorrispondu għal tassoni diġa magħrufin, li qegħdin jiġu użati bħala ‘ankri’ tassonomiċi. Il-morfoloġija tal-qoxra, għalkemm dokumentata b’mod estensiv, irriżultat omoplastika ħafna, u allura insuffiċjenti għad-delimitazzjoni tal-ispeċi meta analizzata b’mod indipendenti, għalkemm tibqa’ siewja fiddokumentazzjoni ta’ varjazzjoni intraspeċifika u sottospeċifika ladarba l-konfini tal-ispeċi ġew definiti anatomikament u ġeografikament. L-iggruppament mhux ristrett ibbażat fuq il-morfoloġija biss jipproduċi gruppi bijoloġikament implawżibbli, u jenfasizza l-ħtieġa li tiġi integrata l-istruttura spazjali fit-teħid ta’ deċiżjonijiet tassonomiċi. Ir-riżultati tagħna juru li l-morfoloġija ġenitali, evalwata fi ħdan qafas morfo-ġeografiku espliċitu, tipprovdi bażi robusta u riproduċibbli għad-delimitazzjoni tal-ispeċi f’radjazzjonijiet mhux adattivi ta’ bebbux tal-art b’kapaċità għat-tixrid limitata. L-approċċ adottat hawn joffri mudell ġeneralizzabbli għar-riżoluzzjoni tal-kumplessità tassonomika f’sistemi oħra li huma morfoloġikament konservattivi u ġeografikament frammentati. Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/144737 2026-01-01T00:00:00Z