Plagigeyeria lewarnei, Grego, 2020

Grego, Jozef, 2020, Revision of the stygobiont gastropod genera Plagigeyeria Tomlin, 1930 and Travunijana Grego & Glöer, 2019 (Mollusca; Gastropoda; Moitessieriidae and Hydrobiidae) in Hercegovina and adjacent regions, European Journal of Taxonomy 691, pp. 1-56 : 22-24

Plagigeyeria lewarnei sp. nov.

urn:lsid:zoobank.org:pub:CC8487E0-169D-4B32-A2AB-F9B34DFB3F3B

Figs 9D , 11B

Type material

Holotype

BOSNIA AND HERCEGOVINA • 1 shell; Republika Srpska , Trebinje Municipality , Gorica, Vrelo “Vruljak 1”, sandy sediment taken by SCUBA dive ca 200 m from the cave entrance ( Fig. 2F ); 42.713736° N; 18.368096° E; 280 m a.s.l.; 6 Sep. 2009; Gergely Balázs. leg.; HNHM MOLL 104176 .

Paratypes

BOSNIA AND HERCEGOVINA • 1 fragmented specimen as for holotype; same data; HNHM MOLL 105099 /; Bosnia and Hercegovina • 7 shells; Republika Srpska , Trebinje Municipality , Vrelo “Tučevac” at right bank of Trebišnjica River, 42.714257° N; 18.303311° E; 280 m a.s.l.; 31 Mar. 2018; J. Grego, M. Olšavský, G. Jakab and M. Kováčiková leg.; SBMNH 626406 /1 fragmented specimen, JG F1336 /6 fragmented specimens .

Dimensions

Holotype: H 1.95 mm; W 1.32 mm; BH 1.21mm; BW 1.05 mm; AH 0.93 mm; AW 1.05 mm.

Etymology

Named after Brian Lewarne from The Devon Karst Research Society, Plymouth UK, who leads the “Proteus Project” hypogean species conservation project in Trebinje and supported this study by extensive consultancy about karst groundwater circulation on the studied area.

Description

Elongate conical shell 1.95 mm high with four convex whorls (apex of holotype missing) separated with rather weak suture. Shell surface covered by slightly sinuated lamellate axial ribs cross-sected by slightly crenated fine spiral cords. Twelve spiral cords are more prominent at the nepionic whorl forming a cancellate surface. Faint spiral ribs continue through the apex where the axial ribs are missing and slowly fade out at the protoconch covered by malleate structure. Umbilicus narrow slit-like and obscured by the strongly reflexed columellar marginal fold. Expanding trumpet-like reflexed aperture with typically sinuated labral margin adapically forward protruding. The ventral shape of the aperture is oval, protruded against the shell outline and slightly labrally depressed, attached to the body whorl at its columellar side. Peristome blunt and strongly outward reflexed along aperture outline.

Differentiating features

The shell morphology and surface sculpture of the new species are closely related to those of P. mostarensis , however the new species differs significantly by its much smaller shell with different shape, by more blunt-rounded apex and by the differently shaped aperture, more protruding at its lower margin. Furthermore the radial malleated cord structure of the first protoconch whorl is weaker in the new species. The new species represents an intermediate between P. mostarensis and P. olsavskyi by its protruding lateral labral profile, however, it differs from the latter by a more closed umbilicus and different shell surface sculpture and by a more smooth protoconch surface.

Habitat

Only scarce, eroded or fragmented shells have been recovered from the spring and cave sediments of the spring at the right bank of Trebišnjica in Trebinje. This suggests a deep cave habitat remote from the spring head or from the hitherto known cave passages. The cave in the type locality drains the karst aquifers north of Trebinje likely from Ljubomirsko Polje (506 m a.s.l.).

Distribution

The new species is so-far known only from the type locality and from the Vrelo “Tučevac” in Trebinje. Fragments resembling this species were found in sediments of “Sušicka Jama” Estavelle at the border with Montenegro.

Figures

Fig. 9 (next page). A. Plagigeyeria erossi sp. nov., Mostar district, Komadinovo Vrelo at right bank of Neretva below Donja Jablanica, holotype (HNHM-MOLL- 104166). B–C. P. erossi sp. nov., type locality, paratypes (JG F0518, JG F1122). D. P. lewarnei sp. nov., Trebinje district, Gorica, cave Vruljak, holotype (HNHM-MOLL-104176). E. P. listicaensis sp. nov., Široki Brijeg, Bilo Vrelo (Lištica 2), holotype (HNHM-MOLL-104168). F. P. listicaensis sp. nov., type locality, paratype (JG F1250). G–H. P. reischuetzorum sp. nov., Dabarsko Polje, Vrelo Vrijeka. G. Paratype (HNHM-MOLL-104165). H. Paratype (JG F1173). I. P. reischuetzorum sp. nov., type locality, holotype (NHMW 111678). J. P. reischuetzorum sp. nov., type locality, paratype (JG F1158). K–L. Travunijana gloeri sp. nov., Dabarsko Polje, Vrelo Vrijeka. K. Holotype (HNHM-MOLL-104418). L. Paratype (JG F1340).

Fig. 11. A. Plagigeyeria ozimeci sp. nov., Vitina, Vrilo Vrioštica, paratype SBMNH 626440. B. Plagigeyeria lewarnei sp. nov., spring Tučevac in Trebinje, SBMNH 626406. Scale bars = 1 mm (SEM SBMNH Vanessa Delnavaz).

Fig. 2. Photos of studied localities in Hercegovina. A. Konjic. Ljuta spring (LT of Plagigeyeria ljutaensis sp. nov.). B. Blagaj, spring Buna (P. mostarensis var.). C. Konjic, spring at left bank of Ljuta Rivulet (LT of P. konjicensis sp. nov.). D. Donja Jablanica, Komadinovo Vrelo (LT of P. erossi sp. nov.). E. Vučija, Sušicka Jama (P. cf. lewarnei sp. nov.). F. Trebinje, Gorica, spring Vruljak 1 (P. robusta and P. lewarnei sp. nov.). Photos: Jozef Grego, Dorottya Angyal and Mário Olšavský.