Shadinia terpoghassiani ( Shadin, 1952 )

Diana Delicado, ladimir Pešić & Peter Glöer, 2016, Unraveling a new lineage of Hydrobiidae genera (Caenogastropoda: Truncatelloidea) from the Ponto-Caspian region, European Journal of Taxonomy 208, pp. 1-29 : 20-24

Shadinia terpoghassiani ( Shadin, 1952)

Figs 8–9 ; Tables 2–3

Pyrgula terpoghassiani Shadin, 1952: 227

Pyrgula terpoghassiani – Akramowski 1952, nom. nud.

New diagnosis

Shell ovate-conic, yellowish, with two weak parallel keels along the body whorl; pyriform aperture; protoconch microsculpture wrinkled; central radular tooth formula 3–C–3/(2)3–3(2); pyriform bursa copulatrix; SRI elongate with a short duct and SRII smaller, globular and without duct; penis gradually tapering and simple, with a distal end tapered and black pigmented; nervous system moderately concentrated (mean RPG ratio = 0.45) and with slight black pigmentation.

Material examined

Type material not specified.

Type locality

ARMENIA: Lake Aiger-Lich, south of Metzamor , Armavia province, 40° 08.573' N, 44°10.270' E, 18 May 2008.

Description

Shell ovate-conic with 4–4.5 whorls, height 2.6–3.6 mm ( Fig. 8 A–C, Table 2 ); periostracum yellowish; protoconch approximately 385 µm wide with 1.3 whorls and nucleus around 125 µm long; protoconch microsculpture wrinkled ( Fig. 8 D); body whorl about ⅔ total length and bearing two weak spiral keels; rest of whorls tall and convex with a deep suture; aperture complete, pyriform, with an inner lip thicker than outer lip; peristome margin slightly sinuate.

Operculum with 2.5 whorls approximately ( Fig. 8 E–F) and muscle attachment area oval and located near the nucleus.

Radula intermediate length (25% total shell length) bearing around 45 rows of teeth; central tooth formula 3–C–3/(2)3–3(2) ( Fig. 8 G–H); lateral teeth formula 3–C–3; inner and outer marginal teeth bearing 17–21 and 19–25 cusps, respectively ( Fig. 8 I).

Pigmentation and anatomy

Head dark brown pigmented from snout to penial base; pigmentation clearer on neck; tentacles also brown pigmented except on ocular lobes; snout as long as wide, with medial lobation. Ctenidium in middle region of pallial cavity with 18–20 gill filaments; osphradium two to three times longer than wide and opposite middle of ctenidium ( Fig. 9 A, Table 3 ).

Nervous system with black pigmentation and moderately concentrated (mean RPG ratio 0.45, Table 3 ); cerebral ganglia equal in size ( Fig. 9 B).

Female genitalia with a capsule gland longer than albumen gland ( Fig. 9 C, Table 3 ); pyriform bursa copulatrix lying against the middle section of the albumen gland; bursal duct longer than bursa length; renal oviduct straight and white from the insertion point of bursal duct to SRII; hereafter black pigmented making one or two loops; two opposite seminal receptacles; SRI pyriform with short duct and SRII smaller, black pigmented, globular and sessile ( Fig. 9 D).

Male genitalia bearing a penis simple, gradually tapering, with a distal end tapered, and black pigmented on the distal section ( Fig. 9 E–F); bean-shaped prostate gland about two times longer than wide ( Fig. 9 G, Table 3 ).

Remarks

Specimens from the type locality varied in shell dimensions and whorl convexity ( Fig. 8 A–C and Shadin 1952: fig. 51), though they were similar in their anatomical features. So far, Shadinia is the only pyrgulinid genus bearing two seminal receptacles (for a morphological review of the Pyrgulinae subfamily see Radoman (1983); the anatomy of Pyrgula Cristofori & Jan, 1832 and Dianella Gude, 1913 is described in Szarowska 2006). Size of seminal receptacles varies slightly between the three anatomically known species, being smaller in S. terpoghassiani than in S. bjniensis . Moreover, some specimens of S. terpoghassiani are larger (shell height S. bjniensis 3.6–4.0 mm, S. terpoghassiani 5.2 mm, see Shadin 1952) and often two weak spiral keels are present in the shell body whorl. Three basal cusps in the central radular tooth are also present in S. akramowskii ( Shadin 1952) . The species of Shadinia here analyzed differ from each other by 0.4% COI p-distances ( Table 4 ).

Ecology and distribution

Armenia and Nakhchivan province of Azerbaijan (Akramowski 1976).

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Figures

Fig. 8. Shell, operculum and radula of Shadinia terpoghassiani (Shadin, 1952) from Lake Aiger-Lich, Armenia. A – C. Shell in front view. D. Protoconch and microsculpture. E – F. Internal and external side of the operculum. G. Rows of teeth of the radula. H. Central teeth. I. Detail of outer marginal teeth.

Fig. 9. Anatomy of Shadinia terpoghassiani (Shadin, 1952) from Lake Aiger-Lich, Armenia. A. Ctenidium and osphradium. B. Partial nervous system. C. Female genitalia. D. Bursa copulatrix and seminal receptacle. E – F. Head of a male and penis. G. Prostate gland. Anatomical abbreviations given in the Material and methods section.

Tables

Table 4. Uncorrected COI p-distances between species of the subfamilies Pyrgulinae and Pseudamnicolinae.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
1. Pseudamnicola lucensis	-
2. Corrosella falkneri	13.7	-
3. Diegus gasulli	12.9	11.2	-
4. Intermaria zagrosensis	15.2	13.7	10.8	-
5. Persipyrgula saboori	14.3	12.6	10.6	6.7	-
6. Intermaria kermanshahensis	15.1	13.5	10.6	0.1	6.5	-
7. Shadinia bjniensis	15.6	14.1	11.7	3.5	8.3	3.6	-
8. Shadinia terpoghassiani	15.9	14.5	12.5	3.7	8.5	3.9	0.4	-
9. Pyrgula annulata	16.8	17.8	14.6	12.2	12.5	12.4	11.6	11.8	-
10. Chilopyrgula sturanyi	17.2	17.1	14.6	13.2	12.8	13.3	12.4	12.6	1.9	-
11. Ohridopyrgula macedónica	16.9	16.5	13.8	12.2	12.9	12.4	11.4	11.6	2.2	1.9	-
12. Xestopyrgula dybowskii	17.4	16.9	14.3	13.2	13.0	13.3	12.2	12.4	3.8	2.8	4.1	-
13. Dianella thiesseana	16.9	16.8	13.4	12.1	13.1	12.2	11.7	11.9	5.8	5.3	5.5	5.5	-
14. Euxinipyrgula milachevitchi	18.5	18.2	13.7	14.1	13.8	14.3	14.0	14.2	11.1	11.3	11.6	10.8	11.4	-
15. Micromelania lincta	18.3	18.4	14.1	14.4	13.9	14.6	14.0	14.2	11.6	11.8	11.8	11.3	11.9	0.6	-
16. Turricaspia sp.	18.9	18.5	14.0	14.3	14.1	14.4	13.8	14.0	11.4	11.6	11.9	11.1	11.8	0.3	0.6	-
17. Falsipyrgula pfeiferi	18.7	18.2	13.5	14.1	13.8	14.3	14.0	14.2	11.0	11.1	11.4	11.0	11.3	0.9	0.9	0.9	-
18. Ginaia munda munda	17.6	16.4	12.9	11.3	11.9	11.4	10.9	11.1	3.3	3.4	4.1	3.3	4.5	10.7	11.1	11.0	10.5	-
19. Ginaia munda sublitoralis	17.8	16.1	13.5	11.9	12.3	12.1	11.7	11.9	3.1	2.6	3.4	2.2	5.0	10.3	10.8	10.7	10.2	2.6	-
20. Macedopyrgula pavlovici	16.3	16.0	13.2	11.7	11.9	11.9	11.1	11.3	2.4	1.9	2.7	2.1	4.0	10.3	10.7	10.6	10.1	1.9	1.4	-
21. Macedopyrgula wagneri	16.9	16.7	13.5	12.4	12.5	12.5	11.7	11.9	2.8	2.2	3.1	2.4	4.1	10.5	11.0	10.8	10.3	1.9	1.7	0.3