Morphology of alimentary system and shell adductor muscles in

Morphology of alimentary system and shell adductor musclesin some species of endemic Baikalian Acroloxidae(Pulmonata, Basommatophora)

A. SHIROKAYA1, P. RÖPSTORF2

1 Limnological Institute of the Siberian Branch of Russian Academy of Sciences,Ulan-Batorskaya street 3, Irkutsk 664033 RUSSIA; e-mail: [email protected] Institute of Geological Sciences, Freie Universität Berlin, Malteser Str. 74-100, 12249Berlin, GERMANY; e-mail: [email protected]

ABSTRACT. Anatomy of alimentary system and shelladductor muscles of ten endemic acroloxid speciesfrom Lake Baikal was studied for the first time. Twotypes of alimentary system have been distinguished inBaikal limpets. The differences have been found inmorphology of odontophore, which are associatedwith the type of feeding. It is shown that the type ofalimentary system found in Gerstfeldtiancylus (Gerst-feldtiancylus) is similar to that of the majority ofnon-baikalian acroloxids. A correlation between theapex position, the form of teleoconch slopes, and themorphology of shell adductors is observed. The studyof closely related acroloxid species allowed to revealadditional taxonomically important characters, and akey to species identification is given.

Introduction

The present paper continues the study of mor-phology of Baikalian endemic acroloxids which wasstarted with investigation of protoconch, adult shell,and radula [Shirokaya et al., 2003]. External andinner morphology of non-baikalian acroloxids wasstudied in detail by Hubendick [1960, 1961, 1962,1969a, 1969b, 1972]. The data on the anatomy ofBaikalian species consist only of information of theradula [Dybowski, 1875; Starobogatov, 1989] andthe copulative apparatus [Hubendick, 1969b; Krug-lov, Starobogatov, 1991]. It was shown in the firstpart of our study, that not all the species describedby Starobogatov [1989] can be distinguished by theirshell and radular morphology. The aim of the presentwork was to find additional characters for the com-parison of closely related acroloxid species. Unfor-tunately, the anatomy of P. frolikhae was not studieddue to lack of material. Here we present the resultsof the study of alimentary system and shell adductormuscles of 10 species of the Baikalian acroloxids.

Material and methods

The study was based on the collection containing10 acroloxid species from 14 stations situated mainly

along the western and northeastern shores of LakeBaikal at depth from 2 to 20 m. The samples werecollected by a group of scuba divers supervised byI.Yu. Parfeevets, during several cruises of the re-search vessels “G. Wereshchagin”, “G. Titov” and“Obruchev”. Additionally, we used the materialfrom the collection of Dr. T.Ya. Sitnikova (Limno-logical Institute SB RAS).

The species were identified using the “compara-tive method”, with the aid of camera lucida [Izza-tullaev, Starobogatov, 1984].

Anatomy was studied by hand dissections of bothalive and fixed molluscs. Gastropods sampled werefixed in 80% ethyl alcohol. Some of them were fixedin 4% formalin and subsequently transferred intoalcohol. Anatomy of the anterior part of the alimen-tary system was studied on the serial sections obta-ined by routine microtome technique. After remo-ving the shell the body was dehydrated, embeddedin paraffin and sectioned 5 µm thick. The sectionswere stained with Heidenhain’s duple stain [Romeis,1953]. Further, the sections were photographed bya digital camera connected to a light microscope andfigured using photos as templates.

All measurements were made using a MBS-1stereomicroscope with a scale (precision 0.1 mm).The height of shell adductors was measured fromthe upper part of the foot sole to the point of adductorconnection to shell.

Statistical analysis was made by Excel 7.0 forWindows.

Abbreviations used in the figures: a.a.l. – left anterioradductor; a.a.r. – right anterior adductor; a.p. – analpore; b.c. – buccal “cartilage” (odontophore); b.m. –buccal mass; b.p. – basal plate; cae. – caecum; col.– collostyle; f. – foot; int.1. – first intestinal loop;int.2. – second intestinal loop; l.p. – liver pores; m.– mouth; m.b. – mantle border; o.a. – original orposterior adductor; od. – odontoblasts; oe. – oesophagus;r.m. – radular membrane; r.s. – radular sac; s.g. –salivary gland; sbr.e. – subradular epithelium; spr.e. –supraradular epithelium; st. – stomach; t. – tentacle;t.m. – tensor musculature.

Îáîçíà÷åíèÿ íà ðèñóíêàõ: a.a.l. – ëåâûé ïåðåäíèéàääóêòîð; a.a.r. – ïðàâûé ïåðåäíèé àääóêòîð; a.p. –

©Ruthenica, 2004Ruthenica, 2004, 14(1): 57-70.

àíàëüíàÿ ïîðà; b.c. – áóêêàëüíûé “õðÿù” (îäîíòî-ôîð); b.m. – áóêêàëüíàÿ ìàññà; b.p. – áàçàëüíàÿïëàñòèíêà; cae. – öåêóì; col. – êîëëàñòèëü; f. –íîãà; int.1. – ïåðâàÿ ïåòëÿ êèøå÷íèêà; int.2. – âòîðàÿïåòëÿ êèøå÷íèêà; l.p. – îòâåðñòèÿ “ïå÷åíè”; m. –ðîò; m.b. – ìàíòèéíûé êðàé; o.a. – îñíîâíîé èëèçàäíèé àääóêòîð; od. – îäîíòîáëàñòû; oe. – ïèùåâîä;r.m. – ðàäóëÿðíàÿ ìåìáðàíà; r.s. – ìåøîê ðàäóëû;s.g. – ñëþííàÿ æåëåçà; sbr.e. – ñóáðàäóëÿðíûé ýïè-òåëèé; spr.e. – ñóïðàðàäóëÿðíûé ýïèòåëèé; st. – æå-ëóäîê; t. – ùóïàëüöå; t.m. – òåíçîðíàÿ ìóñêóëàòóðà.

Results

Pseudancylastrum (Parancylastrum)dorogostajskii Starobogatov, 1989

(Figs. 1A-E, 3A-B)

Alimentary system. The mouth is on the headventral side and surrounded by three lips (Fig. 1A).At the entrance to alimentary canal the mouth epit-helium forms 3 cuticular plates, 2 lateral and 1 dor-sal, which comprise the jaw. Each lateral plate con-sists of 17-19 drop-like scales on average. The dorsalplate lacks scales (Fig. 1C). The jaw in adult indi-viduals is about 1 mm long and consists of 35-37scales. The size of the scales is given in Table 1.The buccal mass is rounded, its length is 1/3 of thesoft body length (Fig. 1D). The odontophore is bi-lobed. The lobes are connected ventrally via a tra-becula (Fig. 3A, B). Histologically the odontophoremainly consists of large, strongly vacuolated cellswith thin walls and central or peripheral nuclei (Figs.1A, 3A). The odontophore is dark-gray in aliveindividuals. Salivary glands are massive, long (Table

1), tubular; they pass through the nerve ring and fuseabove the posterior oesophagus. In transversal sec-tion, initial part of salivary glands consists of 8-10glandular cells with large nuclei, the number of basalcells does not exceed 3-4 (Fig. 1A). The radular saclength is 1⁄2 of the body length (Fig. 1D, Table 1).The radular sheath is tubular, the colostyle lies ven-trally in the lumen on dorsal side. In the zone ofradula formation, subradular epithelium is repre-sented by columnar cells with basal nuclei, the epit-helial cells become flattened at transition to buccalcavity, the nuclei occupy the central position (Fig.1A). The radula in adult specimens consists of 60-78transversal rows. The radular morphology was des-cribed in detail earlier [Shirokaya et al., 2003]. An-terior oesophagus is distinctly expanded. There arelongitudinal ciliary grooves near the entrance ofoesophagus to stomach, which direct the food lumptoward intestine. Oval caecum branches off the sto-mach ventrally, it is directed toward anterior part ofthe body (Figs. 1D, E). Two openings of digestivegland lie at the caecum base, one of them has a largerdiameter than the other. Thin-walled intestine forms2 loops. The first loop (dorsal) lies above the radularsac, slightly shifted rightward. The second loop (ven-tral) is in the distal part of the body, on the left side.The rectal division ends with an anal pore on theright side of molluscan body. The digestive gland islarge and occupies most part of visceral mass.

The shell adductor muscles. There are threeshell adductors, two anterior and one posterior (Fig.1D). Both anterior adductors have an elongatedupper surface, which is obliquely orientated, its pos-terior end being more laterally located than the an-terior end. The ratio of left anterior adductor to right

Table 1. Characterictics of main organs of the alimentary system in studied acroloxid species. L – length, W– width (in mm).

Species L of jawscale

W of jawscale

L of buccalmass

W ofbuccal mass

L ofsalivary gland

L ofradular sac

L of caecum L of softbody

P. dorogostajskii(n=12)

0.05±0.01(0.03–0.06)

0.014±0.006(0.01–0.03)

1.59±0.16(1.33–1.83)

1.45±0.31(1.3–1.7)

6.41±0.97(5–7.5)

1.84±0.21(1.6–2.2)

0.73±0.21(0.45–1)

4.78±0.49(4–5.5)

P. sibiricum(n=10)

0.06±0.01(0.03–0.08)

0.015±0.005(0.01–0.02)

1.61±0.14(1.43–1.9)

1.59±0.1(1.41–1.72)

6.55±0.95(5.4–8)

1.78±0.56(1.64–2.25)

0.9±0.16(0.68–1.13)

4.83±0.43(4.3–5.7)

P. beckmanae(n=10)

0.05±0.01(0.03–0.06)

0.015±0.003(0.006–0.02)

2±0.26(1.65–2.3)

1.62±0.12(1.41–1.8)

5.72±1.01(3.9–7)

0.19±0.49(1.4–1.92)

0.42±0.16(0.19–0.6)

4.24±0.44(3.5–4.8)

G. kotyensis(n=10)

0.07±0.01(0.03–0.09)

0.01±0.006(0.007–0.02)

2.99±0.33(2.55–3.6)

2.28±0.25(1.94–2.6)

7±0.31(6.5–7.6)

2.19±0.33(1.7–2.88)

0.85±0.14(0.68–1.05)

7.48±0.8(6.5–8.94)

G. kozhovi(n=6)

0.06±0.01(0.04–0.07)

0.01±0.003(0.01–0.02)

2.25±0.32(1.78–2.8)

1.82±0.31(1.35–2.4)

5.44±0.41(5–6.1)

1.52±0.19(1.25–1.8)

0.85±0.1(0.4–0.7)

6.55±0.57(5.87–7.5)

G. renardii(n=10)

0.06±0.01(0.05–0.07)

0.02±0.004(0.01–0.02)

2.62±0.32(1.95–3)

1.53±0.3(1–2)

4.81±0.71(4–5.8)

0.89±0.34(0.5–1.4)

0.36±0.14(0.2–0.6)

6.30±0.5(5.68–7)

G. roepstorfi(n=10)

0.08±0.01(0.05–0.1)

0.015±0.005(0.01–0.02)

1.67±0.27(1.3–2)

1.72±0.36(1.56–2.1)

4.96±0.6(4.12–5.8)

1.91±0.12(1.75–2.09)

1.49±0.39(0.95–2.08)

7.82±0.97(7–9.5)

G. benedictiae(n=11)

0.04±0.01(0.02–0.06)

0.01±0.004(0.009–0.024)

0.9±0.18(0.69–1.17)

0.74±0.23(0.54–1.12)

3.84±0.7(2.95–4.6)

1.97±0.27(1.6–2.48)

0.45±0.1(0.29–0.57)

2.29±0.25(2–2.7)

B. boettgerianus(n=10)

0.04±0.01(0.02–0.05)

0.01±0.004(0.01–0.02)

1.65±0.58(0.79–2.35)

1.99±0.6(1.05–2.7)

3.99±1.67(2.55–4.1)

0.57±0.12(0.39–0.71)

0.23±0.1(0.18–0.37)

2.84±0.33(2.4–3.5)

B. kobelti(n=10)

0.05±0.01(0.04–0.07)

0.01±0.003(0.01–0.02)

0.48±0.05(0.4–0.55)

0.54±0.05(0.49–0.61)

1.14±0.22(0.82–1.36)

0.35±0.07(0.27–0.42)

0.14±0.07(0.04–0.23)

1.8±0.15(1.6–2)

58 A. Shirokaya, P. Röpstorf

FIG. 1. A-E — Pseudancylastrum dorogostajskii Starobogatov, 1989, Listvyanka Settlement, 3-15 m, Frolikha Bay, 5m, Maly Kyltygey Island, 2-3 m, Svyatoy Nos Peninsula, 3 m, Khara-Khushun Cape, 3 m, Bolshoy ChivirkuyRiver, 4 m, Listvennichny Island, 6 m. A — sagittal section structure of the anterior part of alimentary system,B – the tooth proper is located on the basal plate, C – jaw, D – general topography of main organs of thealimentary system and the shell adductor muscles, dorsal view, E – sac of crystalline style (caecum), ventralview. Scale bar: A, C, D – 1 mm, B – 0.3 mm, E – 0.09 mm.

ÐÈÑ. 1. A-E — Pseudancylastrum dorogostajskii Starobogatov, 1989, ïîñ. Ëèñòâÿíêà, 3-15 ì, á. Ôðîëèõà, 5 ì,î-â Ìàëûé Êûëòûãåé, 2-3 ì, ï-îâ Ñâÿòîé Íîñ, 3 ì, ì. Õàðà-Õóøóí, 3 ì, ð. Áîëüøîé ×èâûðêóé, 4 ì,î-â Ëèñòâåííè÷íûé, 6 ì. A — ñàãèòòàëüíàÿ ñõåìà ñòðîåíèÿ ïåðåäíåé ÷àñòè ïèùåâàðèòåëüíîé ñèñòåìû,B – òåëî çóáà íà áàçàëüíîé ïëàñòèíêå, C – ÷åëþñòü, D – îáùåå ðàñïîëîæåíèå îñíîâíûõ îðãàíîâïèùåâàðèòåëüíîé ñèñòåìû è ìûøå÷íûõ àääóêòîðîâ ðàêîâèíû, äîðñàëüíî, E – ìåøîê êðèñòàëëè÷åñêîãîñòåáåëüêà (öåêóì), âåíòðàëüíî. Ìàñøòàá: A, C, D – 1 ìì, B – 0,3 ìì, E – 0,09 ìì.

Morphology of some endemic Baikalian Acroloxidae 59

adductor height is 1/2. The posterior adductor loca-ted behind the reduced mantle cavity, is also elon-gated. This muscle is situated almost medially onlongitudinal body axis. The surface area of the pos-terior adductor 1.8-2 times exceeds that of eachanterior adductor.

Pseudancylastrum (Pseudancylastrum)sibiricum (Gerstfeldt, 1859)

(Fig. 2A-C)

Alimentary system. The jaw consists of 38-40lanceolate scales (Fig. 2B). The jaw length is about1.3 mm in adult specimens. The scale size is givenin Table 1. The buccal mass is oval, its length com-prises 1/3 of molluscan body length (Fig. 2A). Theodontophore is dark-gray in alive individuals. Itsmorphology corresponds to that of P. dorogostajskii(Fig. 3A, B). Salivary glands are massive (diameter

not less than 0.3 mm), long (Table 1), in some placespass under oesophagus. The radular sac length is 2/5of the body length (Table 1). The radula in adultspecimens consists of 58-65 transverse rows. Ante-rior part of the oesophagus is expanded. Caecum isoval, branches off the stomach ventrally, directedtoward anterior end of the body (Fig. 2A, C). Thefirst intestinal loop lies in the right part of the body,the second loop is in the left part. Digestive glandis voluminous, occupies 2/3 of visceral mass.

The shell adductor muscles. The right anterioradductor has a massive rounded surface, narrowsto the base (Fig. 2A). The left anterior adductoris slightly larger than the right one, with elongatedsurface, orientated obliquely. It is situated closerto anterior body end than the right adductor. Theratio of left anterior adductor to right adductorheight is 2/3. Posterior adductor has a broad baseand elongated surface, and is situated on the lon-gitudinal body axis. The surface area of posterior

FIG. 2. A-C — Pseudancylastrum sibiricum (Gerstfeldt, 1859), Elokhin Cape, 2-4 m, Listvyanka Settlement, 3-15m, Solontsovy Cape, 3 m, Frolikha Bay, 5 m, Maly Kyltygey Island, 2-3 m, Svyatoy Nos Peninsula, 3 m. A– the alimentary system and the shell adductor muscles, dorsal view, B – jaw, C – caecum, ventral view.D-F — Pseudancylastrum beckmanae Starobogatov, 1989, Solontsovy Cape, 3-4 m, Bolshoy Ushkany Isl., 15 m.D — the alimentary system and the shell adductor muscles, dorsal view (semi-adult specimen), E – jaw, F –caecum, ventral view. Scale bar: A, D – 1 mm, B, E – 0.3 mm, C, F – 0.5 mm.

ÐÈÑ. 2. A-C — Pseudancylastrum sibiricum (Gerstfeldt, 1859), ì. Åëîõèí, 2-4 ì, ïîñ. Ëèñòâÿíêà, 3-15 ì, ì.Ñîëîíöîâûé, 3 ì, á. Ôðîëèõà, 5 ì, î-â Ìàëûé Êûëòûãåé, 2-3 ì, ï-îâ Ñâÿòîé Íîñ, 3 ì. À – ïèùåâàðèòåëüíàÿñèñòåìà è ìûøå÷íûå àääóêòîðû ðàêîâèíû, äîðñàëüíî, Â – ÷åëþñòü, Ñ – öåêóì, âåíòðàëüíî. D-F —Pseudancylastrum beckmanae Starobogatov, 1989, ì. Ñîëîíöîâûé, 3-4 ì, î-â Áîëüøîé Óøêàíèé, 15 ì. D —ïèùåâàðèòåëüíàÿ ñèñòåìà è ìûøå÷íûå àääóêòîðû ðàêîâèíû, äîðñàëüíî (íåïîëîâîçðåëûé ýêçåìïëÿð), E –÷åëþñòü, F – öåêóì, âåíòðàëüíî. Ìàñøòàá: A, D – 1 ìì, B, E – 0,3 ìì, C, F – 0,5 ìì.


adductor 1-1.5 times exceeds that of each anterioradductor.

Pseudancylastrum (Pseudancylastrum)

beckmanae Starobogatov, 1989

(Fig. 2D-F)

Alimentary system. The jaw consists of 35-37scales situated parallel to each other (Fig. 2E). Thescales are drop-shaped, with a rounded base. Thejaw length in adult specimens is about 0.9 mm. The

scale size is given in Table 1. The buccal mass isoval, large; its length is 1⁄2 of the soft body length(Fig. 2D). The odontophore is dark-gray in aliveindividuals. Salivary glands are massive, long, noless than 0.2 mm in diameter. The radular sac lengthis 1/3 of the body length (Table 1). The radula inadult specimens consists of 61-72 transverse rows.Caecum is oval, short, branches off the stomachventrally and directed backward (Fig. 2D, F). Bothintestinal loops are situated above the posterior shelladductor. Digestive gland is large.

FIG. 3. Morphology and frontal section structure (A, C) of the odontophore. A-B — Pseudancylastrum dorogostajskiiStarobogatov, 1989. C-D — Gerstfeldtiancylus kotyensis Starobogatov, 1989. E-F — Gerstfeldtiancylus benedictiae Sta-robogatov, 1989. G-H — Baicalancylus boettgerianus (Lindholm, 1909). A, C, E, G – dorsal view, B, D, F, H– ventral view. Scale bar: a1, B, c1, D – 0.6 mm, a2, c2 – 0.15 mm, E, F – 0.38 mm, G, H – 0.26 mm.

ÐÈÑ. 3. Ìîðôîëîãèÿ è âíóòðåííåå ñòðîåíèå (A, C) îäîíòîôîðà. A-B — Pseudancylastrum dorogostajskii Starobogatov,1989. C-D — Gerstfeldtiancylus kotyensis Starobogatov, 1989. E-F — Gerstfeldtiancylus benedictiae Starobogatov,1989. G-H — Baicalancylus boettgerianus (Lindholm, 1909). A, C, E, G – äîðñàëüíî. B, D, F, H – âåíòðàëüíî.Ìàñøòàá: a1, B, c1, D – 0,6 ìì, a2, c2 – 0,15 ìì, E, F – 0,38 ìì, G, H – 0,26 ìì.


The shell adductor muscles. The right anterioradductor has an elongated surface, straightly orien-tated, its thickness is even throughout (Fig. 2D). Theleft anterior adductor is shorter than the right one,with a broader base and an elongated surface, obli-quely orientated. Both adductors are situated at thesame distance from anterior end of the body. Theratio of left anterior adductor to right adductor heightis 1/2-3/5. Posterior adductor has an elongated sur-

face and is situated on the longitudinal body axis.The surface area of the posterior adductor 2-2.5times exceeds that of each anterior adductor.

Gerstfeldtiancylus (Gerstfeldtiancylus)kotyensis Starobogatov, 1989

(Figs. 3C-D, 4A-F)

Alimentary system. The jaw in adult specimens

FIG. 4. A-F — Gerstfeldtiancylus kotyensis Starobogatov, 1989, Bolshie Koty Bay, 2 m, Listvyanka Settlement, 3-15m, Krest Cape, 5 m, Svyatoy Nos Peninsula, 3 m, Bolshoy Ushkany Isl., 15 m. A – the alimentary system,dorsal view, B – frontal section through a fragment of salivary gland, C – jaw, D – tangential section throughthe radular sheath, E – caecum, ventral view, F – the shell adductor muscles. Scale bar: A, E – 1 mm, B,D – 0.1 mm, C – 0.3 mm, F – 2 mm.

ÐÈÑ. 4. A-F — Gerstfeldtiancylus kotyensis Starobogatov, 1989, á. Áîëüøèå Êîòû, 2 ì, ï. Ëèñòâÿíêà, 3-15 ì,ì. Êðåñò, 5 ì, ï-îâ Ñâÿòîé Íîñ, 3 ì, î-â Áîëüøîé Óøêàíèé, 15 ì. À – ïèùåâàðèòåëüíàÿ ñèñòåìà,äîðñàëüíî, Â – ôðîíòàëüíûé ðàçðåç ÷åðåç ôðàãìåíò ñëþííîé æåëåçû, C – ÷åëþñòü, D – òàíãåíòàëüíûéðàçðåç ÷åðåç ðàäóëÿðíîå âëàãàëèùå, E – öåêóì, âåíòðàëüíî, F – ìûøå÷íûå àääóêòîðû ðàêîâèíû. Ìàñøòàá:A, E – 1 ìì, B, D – 0,1 ìì, C – 0,3 ìì, F – 2 ìì.


consists of 60-68 drop-shaped scales and is about1.2 mm long (Fig. 4C). The scale size is given inTable 1. The buccal mass is large, oval; its lengthcomprises 2/5 of molluscan body length (Fig. 4A).The odontophore is bilobed, consists of large vacu-olated cells with central or peripheral nuclei (Fig.3C, D). In alive individuals, the odontophore is brightred. Salivary glands are long, thin throughout (diameteris not more than 0.1 mm), their initial part expanded(the duct diameter is about 0.4 mm). Secretory cellsof the salivary gland epithelium have large, central orbasal nuclei (Fig. 4B). The radular sac length is 1/3-1/4of the body length. The radula in adult specimensconsists of 60-75 transverse rows. Caecum is oval,branches off the stomach ventrally, directed leftward

(Fig. 4A, E). There are two openings of digestivegland at the caecum base, the dorsal opening beingwider. The first intestinal loop lies in the central partof visceral mass, above the radular sac (slightlyshifted rightward), the second loop is situated in theleft part of the body. Digestive gland is large.

The shell adductor muscles. The right and leftadductors are equally distant from the anterior bodyend, they have an oval apex, widened at base (Fig.4F), and obliquely placed. The ratio of left anterioradductor to right adductor height is 1. The mainadductor has a massive oval surface; it is situatedon longitudinal body axis. The surface area of theposterior adductor 1.9-2 times exceeds that of eachanterior adductor.

FIG. 5. A-D — Gerstfeldtiancylus kozhovi Starobogatov, 1989, Krest Cape, 2 m, Svyatoy Nos Peninsula, 3 m. A –the alimentary system, dorsal view, B – the shell adductor muscles, C – caecum, the left ventral view, D –jaw. E-H — Gerstfeldtiancylus renardii (W. Dybowski, 1884), Bolshie Koty Bay, 20 m, Listvyanka Settlement, 3-15 m,Khara-Khushun Cape, 3 m. E – the alimentary system, dorsal view, F – the shell adductor muscles, G — caecum,ventral view, H – jaw. Scale bar: A, E, G – 1 mm, B, F – 2 mm, C – 0.5 mm, D, H – 0.3 mm.

ÐÈÑ. 5. A-D — Gerstfeldtiancylus kozhovi Starobogatov, 1989, ì. Êðåñò, 2 ì, ï-îâ Ñâÿòîé Íîñ, 3 ì. A –ïèùåâàðèòåëüíàÿ ñèñòåìà, äîðñàëüíî, B – ìûøå÷íûå àääóêòîðû ðàêîâèíû, C – öåêóì, âèä ñëåâà, âåíòðàëüíî,D – ÷åëþñòü. E-H — Gerstfeldtiancylus renardii (W. Dybowski, 1884), á. Áîëüøèå Êîòû, 20 ì, ï. Ëèñòâÿíêà,3-15 ì, ì. Õàðà-Õóøóí, 3 ì. E – ïèùåâàðèòåëüíàÿ ñèñòåìà, äîðñàëüíî, F – ìûøå÷íûå àääóêòîðûðàêîâèíû, G — öåêóì, âåíòðàëüíî, H – ÷åëþñòü. Ìàñøòàá: A, E, G – 1 ìì, B, F – 2 ìì, C – 0,5ìì, D, H – 0,3 ìì.


Gerstfeldtiancylus (Gerstfeldtiancylus)kozhovi Starobogatov, 1989

(Fig. 5A-D)Alimentary system. The jaw is about 1.25 mm

long and consists of 65-70 lanceolate scales (Fig.5D). The scale size is given in Table 1. The buccalmass is large, oval; its length is 1/3 of the bodylength (Fig. 5A, Table 1). In alive molluscs, theodontophore is bright red. The odontophore mor-phology corresponds to that of G. kotyensis (Fig.3C, D). Salivary glands are long, thin (diameter isabout 0.14 mm), their initial part is expanded (theduct diameter is 0.22 mm). The radular sac lengthis 1/3 of the body length (Fig. 5A). The radula inadult specimens consists of 60-68 transverse rows.Caecum is oval, branches off the stomach dorsola-terally, directed leftward (Fig. 5A, C). The firstintestinal loop lies above the radular sac (slightlyshifted rightward), the second loop is situated in theleft half of the body. Digestive gland is large.

The shell adductor muscles. The morphologyof adductors is the same as in G. kotyensis (Fig. 5B).The surface area of the posterior adductor 1.2-1.5times exceeds that of each anterior adductor.

Gerstfeldtiancylus (Gerstfeldtiancylus)renardii (W. Dybowski, 1884)

(Fig. 5E-H)

Alimentary system. The jaw is about 1.2 mmlong and consists of 62-65 lanceolate scales (Fig.5H). The scale size is given in Table 1. The buccalmass is large, rounded, its length is 2/5 of the bodylength (Fig. 5E). In alive molluscs the odonto-phore is bright red. The odontophore morphologycorresponds to that of G. kotyensis (Fig. 3C, D).Salivary glands are long, thin throughout (diame-ter is about 0.17 mm). The radular sac length is1/3-1/4 of the body length. The radula in adultspecimens consists of 70-75 transverse rows. Ca-ecum is oval, short, branches off the stomach dor-

FIG. 6. A-C — Gerstfeldtiancylus roepstorfi Shirokaya, Röpstorf et Sitnikova, 2003, Maly Ushkany Island, 20 m.A – the alimentary system and the shell adductor muscles, dorsal view, B – jaw, C – caecum, left side view.D-G — Gerstfeldtiancylus benedictiae Starobogatov, 1989, Buguldeyka River, 2-2.5 m, Krest Cape, 1.5-5 m, AyayaBay, 5 m. D — the alimentary system, dorsal view, E – jaw, F – caecum, left side view, G – the shelladductor muscles. Scale bar: A, C, D, G – 1 mm, B, E – 0.5 mm, F – 0.3 mm.

ÐÈÑ. 6. A-C — Gerstfeldtiancylus roepstorfi Shirokaya, Röpstorf et Sitnikova, 2003, î-â Ìàëûé Óøêàíèé, 20 ì.À – ïèùåâàðèòåëüíàÿ ñèñòåìà è ìûøå÷íûå àääóêòîðû ðàêîâèíû, äîðñàëüíî, Â – ÷åëþñòü, Ñ – öåêóì,âèä ñëåâà. D-G — Gerstfeldtiancylus benedictiae Starobogatov, 1989, ð. Áóãóëüäåéêà, 2-2.5 ì, ì. Êðåñò, 1.5-5ì, á. Àÿÿ, 5 ì. D – ïèùåâàðèòåëüíàÿ ñèñòåìà, äîðñàëüíî, E – ÷åëþñòü, F – öåêóì, âèä ñëåâà, G –ìûøå÷íûå àääóêòîðû ðàêîâèíû. Ìàñøòàá: A, C, D, G – 1 ìì, B, E – 0,5 ìì, F – 0,3 ìì.


sally, directed leftward (Fig. 5E, G). The firstintestinal loop lies in the central part of visceralmass, above the radular sac, the second loop issituated in the left part of the body. Digestive glandis large.

The shell adductor muscles. The right anterioradductor has an elongated surface and a broad base(Fig. 5F). The left anterior adductor is larger thanthe right one, with an elongated surface, obliquelyorientated. Both adductors are situated at the samedistance from anterior end of the body. The ratio ofleft anterior adductor to right adductor height is 1.The main adductor has massive, oval surface and issituated on the longitudinal body axis. The surfacearea of the posterior adductor 3.7-4 times exceedsthat of each anterior adductor.

Gerstfeldtiancylus (Gerstfeldtiancylus)roepstorfi Shirokaya, Röpstorf et

Sitnikova, 2003

(Fig. 6A-C)

Alimentary system. The horseshoe-shaped jawis about 2 mm long and consists of 71-74 lanceolatescales (Fig. 6B). The scale size is given in Table 1.The buccal mass is rounded, its length is 1/4 of mol-luscan body length (Fig. 6A). In alive individuals, theodontophore is bright red. Salivary glands are long,massive (diameter is about 0.3-0.4 mm), drasticallynarrow in initial part (the duct diameter is not morethan 0.13 mm). The radular sac length is 1/3 of thebody length. The radula in adult specimens consists

FIG. 7. A-C — Baicalancylus boettgerianus (Lindholm, 1909), Svyatoy Nos Peninsula, 3 m, Bolshoy Ushkany Island,15 m. A – the alimentary system and the shell adductor muscles, dorsal view, B – jaw, C – caecum, leftside view. D-F — Baicalancylus kobelti (W. Dybowski, 1885), Angara River (Irkutsk), 3 m. D – the alimentarysystem and the shell adductor muscles, dorsal view, E – jaw, F – caecum, left side view. Scale bar: A – 1mm, B – 0.3 mm, C, D, E, F – 0.5 mm.

ÐÈÑ. 7. A-C — Baicalancylus boettgerianus (Lindholm, 1909), ï-îâ Ñâÿòîé Íîñ, 3 ì, î-â Áîëüøîé Óøêàíèé,15 ì. A – ïèùåâàðèòåëüíàÿ ñèñòåìà è ìûøå÷íûå àääóêòîðû ðàêîâèíû, äîðñàëüíî, B – ÷åëþñòü, C –öåêóì, âèä ñëåâà. D-F — Baicalancylus kobelti (W. Dybowski, 1885), ð. Àíãàðà â ÷åðòå ã. Èðêóòñêà, 3 ì.D – ïèùåâàðèòåëüíàÿ ñèñòåìà è ìóñêóëüíûå àääóêòîðû ðàêîâèíû, äîðñàëüíî, E – ÷åëþñòü, F – öåêóì,âèä ñëåâà. Ìàñøòàá: A – 1 ìì, B – 0,3 ìì, C, D, E, F – 0,5 ìì.


of 60-80 transverse rows. Caecum is oval, long, bran-ches off the stomach dorsolaterally, directed leftward(Fig. 6A, C, Table 1). The dorsal opening of digestivegland is broader than the ventral one. The first intestinalloop lies in the central part of visceral mass, above theradular sac, the second loop is situated in the left partof the body. Digestive gland is large.

The shell adductor muscles. Both anterior ad-ductors have an elongated surface, narrow at thebase (Fig. 6A). The left adductor is closer to theanterior body end than the right one. The ratio ofleft anterior adductor to right adductor height is 1.The main adductor has massive, oval surface and issituated on the longitudinal body axis. The surfacearea of the posterior adductor 1.7-2 times exceedsthat of each anterior adductor.

Gerstfeldtiancylus (Kozhoviancylus)benedictiae Starobogatov, 1989

(Fig. 3E-F, 6D-G)

Alimentary system. The jaw is about 0.9 mmlong and consists of 38-40 variously shaped scales(Fig. 6E). The scale size is given in Table 1. Thebuccal mass is rounded, its length is 1/3 of molluscanbody length (Fig. 6D). In alive individuals, the odon-tophore is dark-gray (Fig. 3E, F). Salivary glands

are long, thin throughout (diameter is about 0.1 mm),in places pass under oesophagus (Fig. 6D).

The radular sac length is 3/4 of the body length.A part of the sac is turned to the ventral side.

The radula in adult specimens consists of 35-40transverse rows. Caecum is oval, up to 0.75 mmlong, branches off the stomach ventrally, directedtoward hind end of the body (Fig. 6D, F, Table 1).The first intestinal loop lies in the central part ofvisceral mass, above the radular sac, the second loopis situated above the main shell adductor. Digestivegland is large.

The shell adductor muscles. Both right and leftshell adductors are equidistant from the anteriorbody end; they have an oval apex, widened at thebase, and obliquely orientated (Fig. 6G). The ratioof left anterior adductor to right adductor height is1. The main adductor has oval surface and is situatedon the longitudinal body axis. The surface area ofthe posterior adductor 1.2-1.5 times exceeds that ofeach anterior adductor.

Baicalancylus boettgerianus(Lindholm, 1909)

(Fig. 3G-H, 7A-C)Alimentary system. The jaw in adult specimens

Table 2. Key to identification of investigated acroloxid species (continued on the facing page)

Species Alimentary systemnum-ber of

jawscales

buccalmass

length /soft body

length

colorof

odon-tophore

salivary glands radularsac

length /bodylength

caecum shape caecumlength

(caecumposition)

caecum direction

P.

dorogostajskii

< 37 < 1/3 gray massive, long 1/2 oval long (ventral) to the anteriorend of body

P. sibiricum > 38 < 1/3 gray massive, long 2/5 elongated long (ventral) to the anteriorend of body

P. beckmanae < 37 1/3-1/2 gray massive, long > 1/3 oval short (ventral) to the posteriorend of body

G. kotyensis < 68 2/5 red in the proximalpart massive, long

1/4-1/3 elongated, atthe baseenlarged

long (lateral) to the left

G. kozhovi < 70 > 1/3 red in the proximalpart massive, long

< 1/3 elongated, atthe baseenlarged

long(dorsal and

lateral)

to the left

G. renardii < 65 2/5 red thin, long 1/4-1/3 oval short (dorsal) to the left

G. roepstorfi > 70 1/3 red massive, long < 1/3 elongated, atthe baseenlarged

long(dorsal and

lateral)

to the left

G. benedictiae < 40 1/3 gray thin, long 3/4 elongated very long(ventral)

to the posteriorend of body

B. boettgeria-

nus

< 30 < 1/3 gray in the proximalpart massive, short

1/6 globular short(dorsal)

—

B. kobelti > 37 < 1/3 gray along the anteriorpart of oesopha-gus massive, short

1/4 oval short (dorsaland lateral)

to the left


is about 0.6 mm long and consists of 25-30 drop-shaped scales (Fig. 7B, table 1). The buccal massis rounded, its length is 1/3 of molluscan bodylength (Fig. 7A). In alive individuals, the odon-tophore is dark-gray (Fig. 3G, H). Salivary glandsare long, their initial part is expanded (the ductdiameter is up to 0.13 mm), the glands graduallynarrow above posterior oesophagus (diameter notmore than 0.05 mm). The radular sac is short, 1/6of the body length. The radula in adult specimensconsists of 45-50 transverse rows. Caecum is glo-bular, branches off the stomach dorsally (Fig. 7A,C). There are two openings of digestive gland atthe caecum base, the left opening is broader thanthe right one. The first intestinal loop lies in thecentral part of visceral mass (slightly shifted right-ward), the second loop is situated in the left part ofthe body. Digestive gland is large.

The shell adductor muscles. Both right andleft shell adductors have oval surface, narrow atthe base, equidistant from anterior body end(Fig. 7A). The ratio of left anterior adductor toright adductor height is 4/5. The main adductoris turned rightward (at about 40° to longitudinalaxis of the body). The surface area of the pos-terior adductor 1.5-1.7 times exceeds that ofeach anterior adductor.

Baicalancylus kobelti (W. Dybowski, 1885)

(Fig. 7D-F)Alimentary system. The horseshoe-shaped jaw

is about 0.92 mm long and consists of 35-45 lance-olate scales (Fig. 7E, Table 1). The buccal mass isrounded, its length is 1/3 of molluscan body length(Fig. 7D). In alive individuals, the odontophore isdark-gray. The odontophore morphology corres-ponds to that of B. boettgerianus (Fig. 3G, H). Sa-livary glands are shorter than in the latter species,thin (diameter is about 0.05 mm), expanded alonganterior oesophagus (diameter to 0.16 mm), abruptlynarrowed in the initial part. The radular sac is 1/4of the body length. The radula in adult specimensconsists of 43-48 transverse rows. Caecum is short,oval, branches off the stomach dorsolaterally, direc-ted leftward (Fig. 7D, F). Dorsal opening of digestivegland is broader than ventral one. The first intestinalloop lies in the central part of visceral mass, thesecond loop is in its apical part (the visceral massin B. kobelti is shifted leftward and gets beyond themantle edge above posterior end of the body) (Fig.7D). Digestive gland is large.

The shell adductor muscles. Both anterior ad-ductors have oval surface and are obliquely orien-tated (Fig. 7D). The right adductor is markedly hig-

Table 2. Key to identification of investigated acroloxid species (finished)

Species Alimentary system Shell adductor musclesposition of firstintestinal loop

left anterioradductor surface

right anterioradductor surface

leftadductor height /

rightadductorheight

position ofposterioradductor

posterior ad-ductor surfacearea / anterior

adductorsurface area

P. dorogostajskii slightly shiftedto the right

elongated,massive, obliquely

orientated

elongated, ma-ssive, obliquely

orientated

1/2 almostbilaterally

symmetrical

1.8-2

P. sibiricum distinctly shiftedto the right

elongated, thin,obliquely orientated

elliptical, massive 2/3 almostbilaterally

symmetrical

1-1.5

P. beckmanae distinctly shiftedto the right


elongated, thin,straightlyorientated

1/2-3/5 almostbilaterally

symmetrical

2-2.5

G. kotyensis slightly shiftedto the right


orientated

elongated, ma-ssive, obliquely

orientated

1 almostbilaterally

symmetrical

1.9-2

G. kozhovi slightly shiftedto the right


orientated

elongated, mas-sive, obliquely

orientated

1 almostbilaterally

symmetrical

1.2-1.5

G. renardii above theradular sac


orientated

elliptical 1 almostbilaterally

symmetrical

3.7-4

G. roepstorfi above theradular sac


orientated

elongated, mas-sive, straightly

orientated

1 almostbilaterally

symmetrical

1.7-2

G. benedictiae above theradular sac


orientated

elongated, mas-sive, obliquely

orientated

1 almostbilaterally

symmetrical

1.2-1.5

B. boettgerianus shifted to theright


elongated, thin,obliquelyorientated

4/5 shifted to theright

1.5-1.7

B. kobelti shifted to the left elongated, thin,obliquely orientated

elongated, thin,obliquelyorientated

1/2 almostbilaterally

symmetrical

1-1.2


her than the left one and situated closer to the anteriorbody end. The ratio of left anterior adductor to rightadductor height is 1/2. The main adductor has ovalsurface and is situated on the longitudinal body axis.The surface area of the posterior adductor 1-1.2times exceeds that of each anterior adductor.

Discussion

Alimentary system

The alimentary system of acroloxids is one ofthe most primitive among basommatophores. Thefragmentary jaw which consists of numerous minutescales and the absence of a gizzard are differencesfrom the ordinary basommatophoran structure [Hu-bendick, 1962]. It is known that the jaw in gastropodsis formed of thin cuticular plates lining the anteriorpart of the buccal region dorsally and laterally. Ac-cording to D.L. Ivanov and Ya.I. Starobogatov[1990], in most freshwater pulmonates there is atendency toward strengthening of dorsal part of thejaw and reduction of lateral parts. On the contrary,Baikalian acroloxids show a complete reduction ofdorsal part of the jaw. The presence of a caecumalso indicates the primitive structure.

In general, two types of alimentary system canbe recognized in Baikalian acroloxids. The type I:jaw scales number from 25 to 40, the buccal massis rounded, its length does not exceed 1/3 of the softbody length, the odontophore is dark-gray, the ra-dular sac length is not more than 1/3 of the bodylength, salivary glands are massive, long, the caecumis oval, it branches off the stomach ventrally, thefirst intestinal loop is shifted to the right mantle edge.This type is characteristic of all studied species ofPseudancylastrum. The type II is characterized by60-74 jaw scales, a very large, oval buccal mass(longer than 1⁄3 of the body length), bright-red odon-tophore, a short radular sac (not longer than 1⁄4-1⁄3of the body length), thin and long salivary glands,an oval caecum branching off the stomach dorsola-terally and directed leftward, the first intestinal looplying in the central part of visceral mass and abovethe radular sac. This type was found in Gerstfeldti-ancylus kotyensis, G. kozhovi, G. renardii and G.roepstorfi. It is known that odontophore, like radularmuscles, contains myoglobin whose amount corres-ponds to the feeding type of molluscs [Alyakrins-kaya, 1979]. An increased tissue haemoglobin ma-king odontophore bright red allows to suggest adifferent feeding type in Gerstfeldtiancylus spp., thatis a more active scraping of food from the substrate.A mixed type of alimentary system is characteristicof the studied species of Baicalancylus: as in Pseu-dancylastrum, the number of jaw scales does notexceed 40, the buccal mass is rounded, its diameteris no more than 1/3 of the body length, the odon-tophore is dark-gray; as in Gerstfeldtiancylus, theradular sac length does not exceed 1/4 of the bodylength, the caecum branches off the stomach dorso-laterally. In B. boettgerianus the first intestinal loop

is shifted to the right mantle edge, in B. kobelti itlies in the central part of visceral mass. Thus, thealimentary system of B. boettgerianus is closer tothe type I in the studied characters, whereas that ofB. kobelti is closer to the type II. Species of Baica-lancylus are characterized by short salivary glandsand a globular caecum.

G. (Kozhoviancylus) benedictiae also possess amixed type of alimentary system with prevalence ofthe type I characters, but it is distinguished by verylong radular sac and caecum.

Most non-baikalian acroloxids possess the ali-mentary system of type II. In particular, the alimen-tary system morphology of Baikalian G. renardii isthe same as in Naearctic Acroloxus coloradensis(Henderson, 1930) and in Palaearctic A. lacustris(Linnaeus, 1758) [Hubendick, 1962, 1969a]. G. ko-tyensis and G. kozhovi are similar to A. improvisusPolinski, 1929 from Lake Ochrid [Hubendick,1960]. Mixed type of alimentary system found inBaicalancylus spp. is characteristic of A. macedoni-cus Hadzisce, 1959 from Lake Ochrid which alsohas a costate shell and a similar body size [Huben-dick, 1969b]. The difference is in the radular mor-phology: the radula in A. macedonicus has a smallnumber of lateral teeth with a broad cutting edge,whereas Baicalancylus spp., on the contrary, possessradula with numerous narrow lateral teeth [Shiro-kaya et al., 2003]. According to B. Hubendick[1969b], A. lacustris and A. coloradensis representa morphological type, which is closely related to theancestral form from which the Baikal and Ochridspecies have evolved. Therefore, the type II of ali-mentary system, characteristic of A. lacustris, A.coloradensis and G. renardii, is probably plesiomor-phic.

The shell adductor muscles

According to B. Hubendick [1962], a strikingfeature in Acroloxus, when compared with basom-matophores in general, is the extraordinarily strongcolumellar muscle and the development of two ad-ditional shell adductors.

Two types of the system of muscular shell ad-ductors can be also recognized in Baikalian acro-loxids. Type I: the posterior adductor is locatedbehind the reduced mantle cavity and shifted to theright mantle edge. Type II: location of the posteriormuscle is almost bilaterally symmetrical. Type I wasfound in B. boettgerianus, type II – in all species ofPseudancylastrum, Gerstfeldtiancylus and B. kobel-ti. The system of muscular adductors of the type Iis characteristic of all studied non-baikalian acro-loxid species [Hubendick, 1960, 1961, 1962, 1969a,1969b, 1972], which allows to suggest that this typeis plesiomorphic.

In studying of morphology of anterior shell ad-ductors it was found that in species with shell apexshifted leftward and bent downward (Pseudancylas-trum spp. and Baicalancylus spp.), the left adductoris always shorter than the right one. Thus, it can be


suggested that the apex position and the shell ad-ductor morphology are correlated in ontogenesis.The position and morphology of left adductor cor-relate with the shape of left teleoconch slope whichis often the only distinguishing character in closelyrelated species of Baikalian acroloxids [Shirokayaet al., 2003]. The form and position of anterior andposterior shell slopes, as well as the degree of back-ward apex displacement, correlate with the positionof main shell adductor.

In comparison of closely related species P. sibi-ricum, P. beckmanae and P. dorogostajskii, it wasfound that P. beckmanae and P. dorogostajskii arethe closest to each other in most studied charactersof alimentary system and shell adductors (Table 2).However, the latter species has a flattened shell witha curved left slope, and, based on morphology ofcopulative apparatus, was separated as the subgenusParancylastrum [Kruglov, Starobogatov, 1991]. Be-sides, P. dorogostajskii differs from two other spe-cies of Pseudancylastrum in the morphology of an-terior shell adductors and the position of the firstintestinal loop. P. sibiricum and P. beckmanae arewell distinguishable in the buccal mass length, thecaecum shape and length, the right adductor morp-hology, and the surface area of main shell adductor.

G. kozhovi, which is conchologically similar toG. renardii and similar to G. kotyensis in the radulastructure, does not differ from the latter species inmost characters of alimentary system (Table 2), ex-cept for the ratio between areas of principal and twoanterior adductors. G. renardii differs from otherstudied species of Gerstfeldtiancylus in the diameterof initial part of salivary glands, the shape of caecum,the position of the first intestinal loop, and the areaof anterior adductors. Therefore, the absence of sig-nificant differences in the anatomy of studied organs,as well as in the shell and radular morphology [Shi-rokaya et al., 2003], confirms the necessity to syno-nymize G. kozhovi and G. kotyensis.

G. roepstorfi differs from all studied species ofGerstfeldtiancylus (Gerstfeldtiancylus) by massivesalivary glands and a small buccal mass. The other

characters of alimentary system and shell adductorsof G. roepstorfi are similar to those of G. kotyensis.

A dwarf species G. benedictiae combines thealimentary system characters of Pseudancylastrumand Gerstfeldtiancylus; it has a very long caecumand is similar to G. kotyensis in the shell adductormorphology.

The two studied species of Baicalancylus (B.boettgerianus and B. kobelti) differ from each otherin the caecum shape, the first intestinal loop position,and in most characters of the muscular shell adduc-tors.

Thus, the study of inner morphology of Baikalianacroloxids allowed to reveal some taxonomicallyimportant characters distinguishing closely relatedspecies which often do not differ conchologically(e.g., P. sibiricum and P. beckmanae, G. kozhovi,G. kotyensis and G. renardii). To identify the acro-loxids, we used such indices as: the ratio betweensurface area of main and anterior shell adductors,the ratio between the buccal mass and radular saclength and the body length, as well as such charactersas the shape, length, and position of caecum. Theratio between height of left and right anterior ad-ductors, and the shape of surface of the anterioradductors can be used to compare closely relatedspecies of Pseudancylastrum. Such characters as thediameter of initial part of salivary glands and theposition of the first intestinal loop are suitable fordistinguishing G. kozhovi-G. kotyensis from G. re-nardii.

Acknowledgements

The authors are grateful to Dr. T.Ya. Sitnikova fororganizing expeditions and valuable suggestions on themanuscript. Special thanks are due to Dr. A.V. Sysoevfor making English version of the manuscript.

The work was supported by the Russian Foundationfor Basic Research (RFBR), projects 01-04-49365a, 98-04-63064k, 99-04-63058k, 00-04-63099k, 01-04-63098k,02-04-63097, 01-04-97230 and Deutsche Forschungsge-sellschaft (DFG), project Ro 2236/1-1,2.

References

Alyakrinskaya I.O. 1979. Haemoglobins and hemo-cyanins of invertebrates (Biochemical adaptationsto environmental conditions). Nauka, Moscow:1-156.

Dybowski W. 1875. Die Gasteropoden-Fauna desBaikal-Sees, anatomisch und systematisch bear-beitet. Mémoires de lAcademie Impériale des Sci-ences de St. Petersbourg, 22 (8): 1-73.

Hubendick B. 1960. The Ancylidae of Lake Ochridand their bearing on intralacustrine speciation.Proceedings of the Zoological Society of London,133 (1): 497-529.

Hubendick B. 1961. Faunistic review of the Ancy-lidae of Lake Ochrid. Archives des Sciences Bi-ologiques, 13 (3-4): 89-97.

Hubendick B. 1962. Studies on Acroloxus (Moll.Basomm.). Göteborgs Kungliga Vetenskaps- ochVitterhets-Samhälles Handlingar, Ser. B, 9(2): 1-68.

Hubendick B. 1969a. A note on Acroloxus colora-densis (Henderson). Journal de Conchyliologie,7 (3): 109-118.

Hubendick B. 1969b. The Baikal limpets and theirphylogenetic status. Archiv für Molluskenkunde,99 (1/2): 55-67.

Hubendick B. 1972. The European fresh-water lim-pets (Ancylidae and Acroloxidae). Informationsde la Société Belge de Malacologie, Serie 1 (8/9):109-126.


Ivanov D.L., Starobogatov Ya.I. 1990. On the prob-lem of origin and evolution of jaw formationsof Mollusca. In: Evolutionary morphology ofmolluscs (Regularities of morpho-functionalchanges of radular apparatus). Sbornik TrudovZoologicheskogo Museya MGU, 28: 202-203 [InRussian].

Izzatullaev Z.I., Starobogatov Ya.I. 1984. Genus Me-lanopsis (Gastropoda Pectinibranchia) and its rep-resentatives living in water-bodies of the USSR.Zoologicheskij Zhurnal, 63 (10): 1471-1483 [InRussian].

Kruglov N.D., Starobogatov Ya.I. 1991. Copulatoryapparatus of Baikalian endemic acroloxids (Gas-tropoda, Pulmonata Acroloxidae). Byulleten Mos-kovskogo Obshchestva Ispytatelei Prirody, otde-leniye Biologii, 96 (6): 82-88 [In Russian].

Romeis B. 1953. Microscopic technique. Inostran-naya Literatura, Moscow: 1-718 [In Russian].

Shirokaya A., Röpstorf P., Sitnikova T. 2003. Mor-phology of the protoconch, adult shell and radulaof some species of endemic Baikalian Acrolox-idae (Pulmonata, Basommatophora). Ruthenica,13(2): 115-138.

Starobogatov Ya.I. 1989. Molluscs of the familyAcroloxidae of Lake Baikal. In: Worms, molluscs,arthropods. Fauna of Baikal: 45-75 [In Russian].

l

Ìîðôîëîãèÿ ïèùåâàðèòåëüíîé ñèñòåìûè ìóñêóëüíûõ àääóêòîðîâ ðàêîâèíû íå-ñêîëüêèõ âèäîâ áàéêàëüñêèõ ýíäåìè÷íûõAcroloxidae (Pulmonata, Basommatophora)

A. ØÈÐÎÊÀß1, Ï. ÐÅÏÑÒÎÐÔ2

1 Ëèìíîëîãè÷åñêèé èíñòèòóò ÑÎ ÐÀÍ, óë. Óëàí-Áà-òîðñêàÿ, 3, 664033, Èðêóòñê, Ðîññèÿ; 2 Èíñòèòóò Ãåîëîãè÷åñêèõ Íàóê, Ñâîáîäíûé Óíèâåð-ñèòåò Áåðëèíà, óë. Ìàëüòåçåð, 74-100, 12249, Áåðëèí,Ãåðìàíèÿ;

ÐÅÇÞÌÅ. Âïåðâûå èññëåäîâàíà àíàòîìèÿ ïèùå-âàðèòåëüíîé ñèñòåìû è ìûøå÷íûõ àääóêòîðîâðàêîâèíû 10 âèäîâ áàéêàëüñêèõ ýíäåìè÷íûõ àê-ðîëîêñèä. Âûäåëåíî 2 òèïà ïèùåâàðèòåëüíîé ñèñ-òåìû ó áàéêàëüñêèõ ÷àøå÷åê. Íàéäåíû ðàçëè÷èÿâ ìîðôîëîãèè îäîíòîôîðà, ñâÿçàííûå ñ òèïîìïèòàíèÿ ìîëëþñêîâ. Ïîêàçàíî, ÷òî òèï ïèùåâà-ðèòåëüíîé ñèñòåìû, íàéäåííûé ó Gerstfeldtiancylus(Gerstfeldtiancylus), ñõîäåí ñ òàêîâûì ó áîëüøèí-ñòâà âíåáàéêàëüñêèõ àêðîëîêñèä. Îòìå÷åíî íàëè-÷èå êîððåëÿöèè ìåæäó ïîëîæåíèåì àïåêñà, ôîð-ìîé ñêëîíîâ òåëåîêîíõà è ìîðôîëîãèåé àääóêòî-ðîâ ðàêîâèíû. Ïðè èññëåäîâàíèè áëèçêèõ âèäîâàêðîëîêñèä âûÿâëåíû äîïîëíèòåëüíûå òàêñîíî-ìè÷åñêè âàæíûå ïðèçíàêè è ïðèâåäåíà îïðåäå-ëèòåëüíàÿ òàáëèöà.


Morphology of alimentary system and shell adductor muscles in

Documents

Transcript of Morphology of alimentary system and shell adductor muscles in