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"A new species of stygobitic isopod from Cerro Colorado Cave, Municipality of Apazapan, near Xalapa, Veracruz, is described. The new species is placed in Mexistenasellus due to the lack of eyes and pigmentation, a head distinct from pereonite 1, and 2 well developed pleonites. Other characters, such as the number of setae in the dactyli of the pereiopods, show slight variations from the original description of the genus. The new species can be distinguished from the previously known 7 species in the genus by the shape of the head, the proportions of the pleotelson and length of uropods. Color in life is pink as is characteristic of the species of Mexistenasellus. A key to the species of Mexistenasellus is provided."

A new cave isopod species of the genusStenasellusDollfus, 1897 (Stenasellidae) from Iran is reported and described. The new species,Stenasellustashanensissp. n.was found in Tashan Cave (Khuzestan province, southwest Iran). A complete description and drawings of the new species are provided. This new species is morphologically close toS.vermeuleniMagniez & Stock, 2000 from Oman.

Mexistenasellus floridensis sp. n. is described from Hole in Wall Cave, Jackson County, Florida. The discovery of this unique isopod nearly doubles the range of the Family Stenasellidae in North America, which was previously known from Oaxaca, Mexico to southern Texas, USA. This is the first stenasellid reported swimming in the water column of a cave, a curious finding for an isopod that belongs to a group that is generally more adapted to inhabiting interstitial spaces. Mexistenasellus floridensis occurs syntopically with the subterranean asellid Caecidotea putea. Both species have been observed swimming in the water column, although neither has apparent anatomical adaptations for swimming as compared to the natatory pereopods of Remasellus parvus, an asellid that occurs in caves in Alachua, Madison and Wakulla counties, Florida.

[A new species of the genus Stenasellus (Asellota, Aselloidea) from karstic waters of Sumatra, S. foresti n. sp., belongs to the same phyletic strain as the other Stenasellidae of the continental and insular Far East (Cambodia, Thailand, Phuket Island, Borneo, Sumatra). Its uropods are short and the tip of the copulatory organs shows a very specific structure of the sternal spur and tergal opening. Nouvelle espece de Stenasellus (Asellota, Aselloidea) des eaux karstiques de Sumatra, S. foresti n. sp. appartient au meme groupe evolutif que les autres Stenasellidae de l'Extreme-Orient continental et insulaire (Cambodge, Thailande, Phuket, Borneo, Sumatra). Ses uropodes sont courts et l'extremite des organes copulateurs montre une structure tres specifique de l'eperon sternal et de l'orifice tergal., A new species of the genus Stenasellus (Asellota, Aselloidea) from karstic waters of Sumatra, S. foresti n. sp., belongs to the same phyletic strain as the other Stenasellidae of the continental and insular Far East (Cambodia, Thailand, Phuket Island, Borneo, Sumatra). Its uropods are short and the tip of the copulatory organs shows a very specific structure of the sternal spur and tergal opening. Nouvelle espece de Stenasellus (Asellota, Aselloidea) des eaux karstiques de Sumatra, S. foresti n. sp. appartient au meme groupe evolutif que les autres Stenasellidae de l'Extreme-Orient continental et insulaire (Cambodge, Thailande, Phuket, Borneo, Sumatra). Ses uropodes sont courts et l'extremite des organes copulateurs montre une structure tres specifique de l'eperon sternal et de l'orifice tergal.]

The author describes a new species of Stenasellus, collected from a spring on the Kenyan Limestone Outcrop near Vinagoni Village (Kilifi District). S. simonsi n. sp., the third species collected in the country, is similar to the other Kenyan species S. ruffoi Messana 1993, and especially to the Somali species S. pardii Lanza 1966. KEY WORDS: Stenasellidae, Kenya, new species.

The historical discovery and the successive stages in our knowledge of the family Stenasellidae Dudich, 1924, are described. Their morphological features; the diagnosis of the family, and an updated list of its genera with the respective numbers of their taxa and their main characteristics are given. Also, the biogeography and the ecology of the group and relations between burrowing behaviour and general adaptation to life in all types of continental underground waters, are discussed. Next, the putative evolutionary history of the family is presented, taking into account the active dispersal of these isopods and also the role of Quaternary events: the development of aridity in the northern tropical zone and the occurrence of glaciations in the temperate zones of the Northern Hemisphere. Their general biological adaptation to the absence of circadian stimuli is examined vis-a-vis the fact that biological rhythms are synchronized with the annual flooding events in the subterranean environment. Decouverte historique et progres successifs de la connaissance de la famille des Stenasellidae Dudich, 1924. Caracteres morphologiques originaux; diagnose de la famille; liste mise a jour des genres, nombre de leurs taxons et principales caracteristiques. Biogeographie et ecologie du groupe; relations entre le comportement fouisseur et l'adaptation a la vie dans tous les types de milieux des eaux souterraines continentales. Histoire evolutive presumee de la famille, tenant compte de la capacite d'expansion active de ces Isopodes et du role des evenements quaternaires: developpement du climat aride dans la zone nord-tropicale et intervention des glaciations dans les zones temperees de l'hemisphere nord. Adaptation generale des processus biologiques a l'absence de stimuli externes circadiens, ces processus etant rythmes par la pulsation annuelle du flux des eaux dans l'environnement souterrain, qui joue le role d'un stimulus circannien.

BIOGEOGFIAPHIA - vol‘ XIX - 1997 (Pubblicato il 31 ottobre 1998) Gli effetti delle variazioni climatiche pleistoceniche sulla dinamica dei popolamenti animali e vegetali nella Penisola italiana Uso di marcatori biochimici per lo studio del popolamento stigobio di Sardegna: gli Asellota (Crustacea Isopoda) ROBERTO ARGAN O, GIUSEPPE MESSANA *, ELVIRA DE MATTHAEIS, MARINA COBOLLI, VALERIO KETMAIER Dz'pzz7'tz'mento di Bi0[0gz'zzAm'mzz/6 e a'el[’Uomo, Uni:/ersitiz di Roma qLa Szzpienzzz” * Centre 512' Studio per la Fzzzmistiaz ed Ecologizz Tropiazli, C.N.R., Firmze Keywords: Paleogeography, Genetic divergence, Stygobitic fauna, Stemzxellus, Prozzse/I115. SUMMARY Levels of genetic divergence on several populations belonging to different Asellota species, obtained via allozymic markers, are reported and discussed with the aim to shed light on the dynamic of colonization of Sardinian surface and underground freshwaters. Two Families of Aselloru are here considered: Asellidae (genus Prorttrllm) and Stenasellidae (genus Steizzzsel/21:). Up to date only three species of Stenasellidae were known for Sardinia (S. rzmwitzzzi, S. 22zu'agicu.r, S. rzssaigg/qxii 5.1.). The genus Przmre//12.: is present in Sardinia with populations showing different levels of adaptation to underground environment. We studied three strictly stygobitic populations, five epigean Sardinian populations and one population from Giordania, in the area of the type locality of the species P. coxrzlis, in order to better understand pattern of phylogenetic relationships and colonisation dynamic. Levels of genetic divergence allowed us to hypothesise a model of colonisation of Sardinian freshwaters based on multiple dispersal events. Quaternary climatic changes may be considered responsible of the presently observed pattern of genetic differentiation and of the colonisation of underground waters. Recent researches have led to discover an high number ofSfez1a5e/[Ia populations: levels of genetic divergence among them allowed us to recognise six species at least, whose phylogenetic relationships are discussed taking into account palaeogeographic events that alicecred Sardinia from Miocene to date. INTRODUZIONE Le acque sotterranee della Sardegna racchiudono un importante capitolo della storia del popolamento anirnale dell’isola, ben lontano dall’essere cornpletamente scritto. Questo ambiente, benche avaro di informazioni, costituisce un inesau— ribile campo di studi che consente, tra l’altr0, di saggiare il Valore inforrnativo di rnetodologie diverse, di rnoda e non, messe a confronto. Da qualche anno stiamo tentando drrealizzare un programma organico di ricerche sugli isopodi dulcacquicoli dell’isola, sia per quanto riguarda gli ambien— ti di superficie che quelli sotterranei. Si tratta di organismi di grande interesse biogeografico e, piu in generale, evoluzionistico. Infatti, come e stato piii volte affermato, il rnonofiletismo, che e alla base del- l’intero ordine degli Isopodi, garantisce una sostanziale ornogeneita organizza—

Troglobitic isopods of the family Asellidae, comprising about 42 species (Fleming, 1973), are widespread in the eastern United States, mostly in non-glaciated areas, but extending into some glaciated parts of Illinois and Indiana. To the west, troglobitic asellids range to central Kansas, Oklahoma and Texas. West of this area, if we exclude the 4 Mexican species of Mexistenasellus (Cole and Minckley, 1972; Magniez, 1972; Argano, 1973) which belong to a separate family, Stenasellidae (Henry and Magniez, 1968, 1970), only 2 troglobitic asellids are known from North America: Asellus californicus Miller (1933) from northern California and Conasellus pasquinii Argano (1972) from Veracruz state, Mexico. The 3 new species of western troglobitic asellids described herein extend the records of blind asellids in North America south to Chiapas state, Mexico, and north to central Alberta, Canada (ca. 53''N), and add a second species from California. The new species from Chiapas is very similar to Conasellus pasquinii Argano (1972); the new asellids from Alberta and California show no close affinities with known species. The generic status of North American species of Asellus is still unsettled. Henry and Magniez (1970) divided tlie species between Conasellus Stammer (1932) and ,Pseudobaicalasellus Henry and Magniez (1968) except A. tomalensis Harford and ... A. californicus Miller, which they believed to be closely related to far-eastern forms belonging to Aseltus (Asellus) and Nipponasellus Matsumoto (1962). I have indi" cated that this is unlikely for A. tomalensis (see Bowman, 1974); the case oi A. californicus will be discussed later in this paper. ' '""'*