Recent studies have revealed high local diversity and endemism in groundwaters, and showed that species with large ranges are extremely rare. One of such species is the cave shrimp Troglocaris ...anophthalmus from the Dinaric Karst on the western Balkan Peninsula, apparently uniform across a range of more than 500 kilometres. As such it contradicts the paradigm that subterranean organisms form localized, long‐term stable populations that cannot disperse over long distances. We tested it for possible cryptic diversity and/or unexpected evolutionary processes, analysing mitochondrial (COI, 16S rRNA) and nuclear (ITS2) genes of 232 specimens from the entire range. The results of an array of phylogeographical procedures congruently suggested that the picture of a widespread, continuously distributed and homogenous T. anophthalmus was wrong. The taxon is composed of four or possibly five monophyletic, geographically defined phylogroups that meet several species delimitation criteria, two of them showing evidence of biological reproductive isolation in sympatry. COI genetic distances between phylogroups turned out to be a poor predictor, as they were much lower than the sometimes suggested crustacean threshold value of 0.16 substitutions per site. Most results confirmed the nondispersal hypothesis of subterranean fauna, but the southern Adriatic phylogroup displayed a paradoxical pattern of recent dispersal across 300 kilometres of hydrographically fragmented karst terrain. We suggest a model of migration under extreme water‐level conditions, when flooded poljes could act as stepping‐stones. In the north of the range (Slovenia), the results confirmed the existence of a zone of unique biogeographical conflict, where surface fauna is concordant with the current watershed, and subterranean fauna is not.
The complete re-description of Caucasian local endemic stygobitic atyid shrimp Troglocaris (Xiphocaridinella) jusbaschjani Birštein, 1948 is firstly presented after its original description given by ...Dr. Ya. A. Birštein (1948) under the name Troglocaris schmidti jusbaschjani. The species is still known exclusively from the type locality, hydrogen sulfide bathes of the small Agura River, Sochi area, Russian Federation. Remarks on morphology, coloration of both females and males and data on ecology of Troglocaris (Xiphocaridinella) jusbaschjani Birštein, 1948 as well as remarks on morphology of relative congeneric species from Caucassus, Troglocaris (Xiphocaridinella) kutaissiana (Sadowsky, 1930) (type species of the subgenus) and Troglocaris (Xiphocaridinella) fagei Birštein, 1939, are provided. Discussion on the validity of some subgenera within the genus Troglocaris s. str. Dormitzer, 1853 are also presented.
Three Dinaric subgenera of cave shrimps from the genus Troglocaris s. l.: T. sg. Troglocaris Dormitzer, 1853 (=Troglocaris s. str.), T. sg. Spelaeocaris Matjašič, 1956 and T. sg. ...TroglocaridellaBabić, 1922 comprise 12 currently known species and phylogenetic lineages. On the basis of the results of previous molecular studies and the extensive morphometric analysis, appropriateness of several former and the existence of some new metric descriptors are examined by multivariate statistical methods. In discriminant function analyses (DFA), all subgenera are distinctly separated even when only sexually non‐dimorphic characters are used. Since considerable number of these characters is acknowledged, a joined analysis of both sexes is proven to be appropriate for the identification of the subgenera. Characters for the species recognition of Spelaeocaris and Troglocaridella females are provided. In the subgenus Troglocaris s. str., molecularly recognized phylogroups are separated by DFA despite the expressed clinal variation. Also, minimum spanning tree (MST) demonstrates the existence of considerable morphological differences. The amounts of morphological difference (indicated by the length of the MST lines) and genetic difference are concordant i.e. morphological differences among the subgenera exceed the ones within the subgenera.
Zusammenfassung
Drei dinarische Untergattungen der Höhlengarnelen aus der Gattung Troglocaris s. l.: T. sg. Troglocaris Dormitzer, 1853 (=Troglocaris s. str.), T. sg. Spelaeocaris Matjašič, 1956 und T. sg. TroglocaridellaBabić, 1922, bestehend aus 12 Arten und phylogenetischen Linien. Die molekulare Analyse von früheren Studien war die Grundlage für unsere morphometrischen Untersuchungen. Eine umfangreiche morphometrische Analyse zeigt die Angemessenheit der früheren und die Existenz der neuen morphometrischen Merkmale. Bei der Diskriminanzanalyse wurden die sexuell dimorphen morphometrischen Merkmale nicht berücksichtigt. Weil eine Reihe von sexuell nicht dimorphen morphometrischen Merkmalen gefunden wurde, ist eine gemeinsame Analyse beider Geschlechter geeignet für die Identifizierung der Untergattungen. Merkmale für die Identifizierung der Arten von der Untergattungen Spelaeocaris und Troglocaridella werden diskutiert. Trotz der graduellen Variation ist es uns gelungen, Phylogruppen von Troglocaris s. str. zu erkennen. Der minimale Stammbaum (MST) bestätigt die Existenz von erheblichen morphologischen Unterschieden. Die Beträge der morphologischen Unterschiede (angedeutet durch die Länge der MST‐Linien) und genetische Unterschiede sind übereinstimmend: Morphologische Unterschiede zwischen den Untergattungen sind größer als innerhalb der Untergattungen.
Cave shrimps of the subgenus Troglocaris (Atyidae), exhibit high variability in rostral length and dentition. In shrimp populations that co-occur with the amphibian predator Proteus anguinus, longer ...rostra armed with more numerous teeth are recorded. These shrimps are also larger than those living in a presumably Proteus-free environment. Discrepancies between molecularly established phylogenetic relationships and distributions of rostral length, as well as body size, directed our search towards possible environmental influences. These discrepancies suggest that rostral shape is not a reliable taxonomic character in some generic and many specific diagnoses in Atyidae. We discuss some taxonomic consequences of sexual and ontogenetic rostral differences with regard to the molecular phylogenetic tree. In preliminary laboratory observations, no frontal attack by Proteus was successful on shrimps with long rostra. Proteus also needed more time to swallow shrimps with long rostra.
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