Institute of Parasitology SAS, Hlinkova 3, 040 01 Košice, Slovakia [spakulma@saske.sk, vasilko@saske.sk, oros@saske.sk]
*corresponding author

Received: 4.4.2011; Accepted: 6.5.2011; Published: 18.8.2011

A distinct morphological form of rare parasite Skrjabinocoelum petrowi Kurashvili, 1953, S. petrowi f. pannonensis was found during spring migration of Jack snipe Lymnocryptes minimus Brünnich, 1764 in East Slovakia. The newly described form differs from the originally described S. petrowi from Georgia in 1) greater measurements of body and organs; 2) pharyngeal position of genital pore; 3) post-testicular position of ovary; 4) uterus exceeding behind testes to cyclocoel; 5) occurrence of the parasite in Central Europe. These features contribute to the knowledge on potential morphological variability of S. petrowi. Providing that relative stability of these features is confirmed in new material, further awaiting findings may serve as a basis for description of the new taxon.

flukes, morphological variability, Skrjabinocoelum petrowi, Jack snipe, Central Europe

Diagnosis of the cyclocoelid genus Skrjabinocoelum Kurashvili, 1953 and description of S. petrowi Kurashvili, 1953 have been based on a single specimen dissected from the body cavity of a Jack snipe Lymnocryptes minimus Brünnich, 1764 in Georgia, February 23, 1950 (Kurashvili 1953, 1957). According to literature data, the species has been found also in common snipe Gallinago gallinago (Linnaeus) from Azerbaidzhan (Fejzullaev 1980; Kanev et al. 2002), thus confirming that it might belong to geographic ’southern form’ sensu Dogiel (1963). To date, no other congeneric species has been described; the taxon is the only member of the subfamily Skrjabinocoelinae Dronen, 2007. The present paper describes the new form of S. petrowi found in East Slovakia in the type host Jack snipe, whose European north-breeding population winters either from North-west Europe to the Iberian Peninsula or in central and eastern Africa, and in southern and south-eastern Asia to Vietnam (Hudec et al. 2005). The Slovak locality is situated on the northern border of Pannonian environmental zone. Due to the very rare occurrence of S. petrowi and existence of its diverse morphological forms, the paper is applied also to a discussing up-to-date knowledge on variability within the group of cyclocoelid trematodes (Macko 1959, 1964, 1965; Macko & Feige 1960 and others).

The specimen of S. petrowi f. pannonensis was recovered from a single host L. minimus (Charadriiformes: Scolopacidae) out of 33 examined Jack snipes in vicinity of Senné (Eastern Slovakia). The birds were captured in spring (March – April) during the period from 1965 to 1970. The isolated trematode was fixed in alcohol-formol-acetic acid (AFA), stained with Semichon’s carmine, de-stained in acid ethanol, dehydrated in ethanol series, cleaned in clove oil and mounted in Canada balsam. Measurements and drawings were taken using light microscope Olympus BX equipped with AnalysisDocu programme and a drawing tube. Measurements are given in μm unless stated otherwise.

Based on the observed differences, the trematode found in Slovakia could represent a new species from traditional taxonomical point of view. However, we could not assess a range of morphological variability within a taxon represented by a single type specimen. An intraspecific morphological variation within other members of the family Cyclocoelidae differs from genus to genus (Macko 1959, 1964, 1965; Macko & Feige 1960). For instance, the genus Haematotrephus Stossich, 1902 (Cyclocoelidae, Trematoda) is characterised by vitelline fields not united at posterior body end (Kanev et al. 2002). Despite that, Macko (1960) analysed 51 specimens of Haematotrephus lanceolatum (Wedl, 1858) dissected from a single whimbrel Numenius phaeopus (Linnaeus, 1758), and found that vitelline branches were more or less converged in 4 specimens and apparently united in 7 other worms. Similar results were obtained in H. lanceolatum collected from the ruff Philomachus pugnax (Linnaeus, 1758) (Macko 1964). On the other hand, the genus Uvitellina is characterised by posteriorly united vitelline fields, and no exception was found among 11 specimens of the species U. vanelli (Rudolphi, 1819) (Macko 1959). It is likely that united vitelline branches represent rather stable morphological feature in the family Cyclocoelidae. The only cyclocoelid with vitelline fields confluent both anteriorly and posteriorly is the genus Skrjabinocoelum and therefore, the trematode found in Slovakia, apparently belongs here.

Another important ‘generic’ taxonomic feature of cyclocoelid trematodes is mutual position of gonads (Macko 1964). Among all genera, the only Skrjabinocoelum is characterized by testes in transverse row (Kanev et al. 2002; Dronen et al. 2006, Dronen 2007) which also proves the generic affiliation. However, the type specimen shows testes and ovary between them in one transverse line (Kurashvili 1953) while the ovary of the newly described form lies slightly behind the right testis. It confirms the designation of S. petrowi f. pannonensis, together with the differences in size of body and organs and other morphological characters.

Based on recently known data on morphological variability of cyclocoelid flukes, it is not possible to decide unambiguously whether morphological characters of the newly described form represent a variance within S. petrowi, or whether they may represent characteristics of a new taxon. According to ICZN (2000), the first Skrjabinocoelum specimen found in Slovakia should be published as a distinct morphological form (a term that denotes infrasubspecific rank). There is a low chance of regaining abundant material of this rare parasite in short future, because the host, Jack snipe, is one of the birds to which the Convention on Migratory species, African-Eurasian Waterbird Agreement (AEWA), applies and one of the key issues is species and habitat conservation (http://www.cms.int/species/aewa/aew_bkrd.htm). However, some helminth surveys still appear dealing either with bird carcasses (e.g. Foronda et al. 2009) or the studies are based on yet unidentified material from ancient field collections (e.g. Blend & Dronen 2008; Mutafchiev & Georgiev 2009). Therefore, the problem opened here might have a solution.

The publication has been created within realisation of the project “Centre of Excellence for Parasitology” (Code ITMS: 26220120022), based on the support of Operational Programme”Research & Development” funded from the European Regional Development Fund (rate 0.9).