See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/249282733 Revision of the genus Acavus from Sri Lanka (Gastropoda : Acavidae) Article in Journal Molluscan Studies · May 2000 DOI: 10.1093/mollus/66.2.217 CITATIONS READS 12 442 1 author: Bernhard Hausdorf University of Hamburg 234 PUBLICATIONS 4,656 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Biogeographical analysis of land Snails Diversity along the River Niger and River Benue Catchment Areas, Nigeria View project Systematics and biogeography of Caucasian continental gastropods View project All content following this page was uploaded by Bernhard Hausdorf on 22 February 2018. The user has requested enhancement of the downloaded file. J. Moll. Stud. (2000), 66, 217–231 © The Malacological Society of London 2000 REVISION OF THE GENUS ACAVUS FROM SRI LANKA (GASTROPODA: ACAVIDAE) BERNHARD HAUSDORF1 and KALIKA K. PERERA2 1Zoologisches Institut und Zoologisches Museum der Universität Hamburg, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany; 2134-12, Highlevel Road, Maharagama, Sri Lanka. (Received 22 December 1998; accepted 2 October 1999) ABSTRACT maintained H. fastosus Albers, 1854 and H. prosperus Albers, 1857 as separate species The genus Acavus from Sri Lanka includes three besides the three already mentioned, A. haema- species, Acavus haemastoma (Linnaeus), Acavus stoma, A. superbus and A. phoenix, because he superbus (L. Pfeiffer) and Acavus phoenix (L. Pfeif- has not seen specimens of these forms. Randles fer) with two subspecies, Acavus phoenix phoenix (L. Pfeiffer) and Acavus phoenix castaneus new (1900) published an important comparative subspecies. The conchological and anatomical differ- anatomical investigation of the anatomy of the ences between these species, as well as their intra- Acavus species. He followed the classification specific variation are described. Their distribution is of Pilsbry (1890a). Sykes (1900) and Gude shown on maps and all locality records are listed. The (1914) also followed Pilsbry (1890a). However, presence of extensive intraspecific polymorphism, the Sykes (1900) already suspected that A. prosperus development of geographical subspecies and the pre- was only a variety of A. haemastoma and that sumable hybridization between some species show A. fastosus was also closely allied to A. haema- that the Acavus species are not isolated relict species, stoma. Barnacle (1962) classified A. fastosus but that speciation is in progress and that the radiation of the Acavus species is probably much younger than and A. prosperus as varieties of Acavus haema- the radiation of the acavid genera. The three Acavus stoma (Linnaeus). On the other hand, he ranked species are not acutely endangered at present. In Acavus roseolabiatus (Nevill, 1881), formerly contrast to many other land snails, there is no risk of a considered a variety of Acavus superbus, as dis- rapid decline of the Acavus species due to deforesta- tinct species. In the most recent survey of the tion, because these species also occur in synanthropic landsnail fauna of Sri Lanka, Ratnapala (1984) habitats. accepted A. roseolabiatus as a separate species and also listed A. fastosus and A. prosperus as distinct species. INTRODUCTION The exact distribution of the Acavus species in Sri Lanka was poorly known until Barnacle The Acavidae of Sri Lanka early attracted the (1962) presented a distribution map. Unfortun- attention of naturalists because they are colour- ately, Barnacle did not list exact localities. ful and attractive. The Acavidae are repre- Therefore, it is not clear on what data his map is sented in Sri Lanka by two endemic genera, based. There are voucher specimens from only Acavus and Oligospira. Already Linnaeus (1758) six localities in Barnacle’s collection in the described the first Acavus species, A. haema- BMNH. Barnacle (1962) stated that each Acavus stoma. Colour and form varieties of this species species inhabits a separate area and that the were described later by Born (1778), Albers different species do not occur sympatrically. (1854, 1857), Westerlund (1887) and Pilsbry Since Barnacle (1962) has not shown or dis- (1890a, 1890b), partly as separate species. The cussed the distribution of the various ‘varieties’, two other species recognized in the present it remained unclear which ‘varieties’ represent paper, A. superbus (L. Pfeiffer, 1850) and A. geographical subspecies and which represent phoenix (L. Pfeiffer, 1854), were described a only infrasubspecific variations. Only recently century after Linnaeus by L. Pfeiffer (1850, more exact locality data of the various Acavus 1854). Finally, additional colour varieties of A. forms became available (Perera, 1992; Priya- superbus were described by L. Pfeiffer (1856) darshana, 1995; Raheem & Butterworth, 1998). and Nevill (1881). Acavus is essentially restricted to the wet In his revision of Acavus, Pilsbry (1890a) zone in the south-west of Sri Lanka, including 218 B. HAUSDORF & K.K. PERERA the foothills of the central massif, up to more Remarks. The general anatomy of Acavus has than 600 m altitude. One Acavus species is also been described in detail by Randles (1900). In present at Ritigala, an isolated 600 m altitude agreement with the findings of Randles (1900), patch of moist forest within the north-central no constant differences in anatomical charac- dry zone. Sri Lanka’s south-western wet zone ters besides the penial structure between the (annual precipitation more than 2500 mm) was Acavus species have been found. Therefore, mostly covered by evergreen rain forest, but only the penial structure is described in detail in now the remaining patches of primary forest the following. are being severely fragmented. The body colour of the Acavus species varies In this paper, we present a revision of the intraspecifically between light brownish or taxonomy of the Acavus species of Sri Lanka greyish to chocolate brown or black. No con- and discuss their distribution. stant interspecific differences have been found. Acavus haemastoma (Linnaeus, 1758) MATERIAL AND METHODS (Figs 1–13, 19) Counting of the shell whorls follows Kerney & Helix Haemastoma Linnaeus, 1758: 773. Locus Cameron (1979: 13). Measurements from some popu- typicus: not given. lations are given to illustrate the size variation. If there are distinct size variations between populations, Helix Melanotragus Born, 1778: 400. Locus typi- measurements of some of the extreme populations cus: not given. are given. The terms proximal and distal refer to the Helix Haematragus Born, 1778: 400. Locus typi- position in relation to the gonad. In the locality lists cus: not given. the localities are ordered according to their coordi- Helix fastosa Albers, 1854: 213. Locus typicus: nates. ‘peninsula Malaccana’. In most museum collections there are numerous Helix prospera Albers, 1857: 93, pl. 1 fig. 7–8. Acavus samples from ‘Ceylon’. Such inexact locality Locus typicus: ‘Insula Ceylon’. data are useless. Therefore, only samples with more Helix (Acavus) haemastoma var. aliostoma exact locality data are listed. Most samples with exact locality data have been collected in the last decade Westerlund, 1887: 187. Locus typicus: ‘Point de and are concentrated in a few collections. Galle’. Abbreviations for collections: BMNH: The Natural Helix (Macroon [Acavus]) haemastoma var. History Museum, London; HEM: Collection J. Hem- conus Pilsbry, 1890a: 79, pl. 16 fig. 7. Locus typi- men, Wiesbaden; LIN: Collection G. Lindner, Rein- cus: not given. bek; PER: Collection K. K. Perera, Maharagama; Helix haemastoma var. concolor Pilsbry, 1890b: SMF: Senckenberg-Museum, Frankfurt a. M.; ZMB: 59. Locus typicus: not given. Zoologisches Museum der Humboldt-Universität, Acavus haemastoma monochroa Pilsbry, 1931: Berlin; ZMH: Zoologisches Institut und Zoologisches 100. Nomen novum pro Helix haemastoma var. Museum der Universität Hamburg Voucher specimens from the collection Perera have concolor Pilsbry, 1890 non A. E. Férussac, 1821. been deposited in the National Museum of Sri Lanka in Colombo. Shell (Figs 1–9): conical-globular; with 4–4½ Additional abbreviations: det. anat. ϭ anatomically convex whorls; protoconch with 2½–¾ whorls, determined; D ϭ shell diameter; H ϭ shell height. pinkish, yellowish or brownish, with incon- spicuous growth-ridges, more or less distinctly delimited from the teleoconch; teleconch with inconspicuous growth-ridges; whitish, whitish SYSTEMATIC ACCOUNT with a variable brownish banding pattern or unicoloured brownish; body whorl rounded Acavus Montfort, 1810 or very obtusely angular, slightly or distinctly descending towards the aperture; aperture Acavus Montfort, 1810: 235. Type species (by oblique elliptical; the insertions of the aperture original designation): Helix haemastoma Lin- are connected by a heavy parietal callus; peri- naeus, 1758. stome thickened, expanded and reflexed; colum- ellar margin of the peristome oblique, adnate to Diagnosis: Acavus differs from the depressed- the base, not truncated, with a curved excava- globular Oligospira in the conical-globular shell tion at the place of the umbilicus, the peristome with more than 3½ whorls and the lack of a and the parietal callus are rose, purple, brown distal constricted penis section. or whitish with a rose or brown touch. REVISION OF ACAVUS 219 Measurements. f. haemastoma: Kathaluwa (n ϭ x¯ ϭ 47.0 Ϯ 3.4 mm; D/H: 0.88–1.13, x¯ ϭ 1.00 Ϯ 50); D: 30.5–46.2 mm, x¯ ϭ 38.8 Ϯ 3.1 mm; H: 0.06. 31.1–47.6 mm, x¯ ϭ 38.2 Ϯ 3.1 mm; D/H: 0.92–1.15, x¯ ϭ 1.02 Ϯ 0.05. Penis (Figs 10–12): The opening of the vas f. melanotragus: Baddegama (n ϭ 25): D: deferens is situated in a longitudinal furrow 31.6–41.6 mm, x¯ ϭ 37.5 Ϯ 2.6 mm; H: 32.3–40.1 bordered by two tumid lips. The furrow is mm, x¯ ϭ 37.2 Ϯ 1.9 mm; D/H: 0.82–1.10, enclosed by a high, u-shaped, more-or-less x¯ ϭ 1.01 Ϯ 0.06. Elpitiya (n ϭ 25): D: 40.8–52.7 corrugated and ridged thickening.