Underexplored diversity of gill monogeneans in cichlids from Lake Tanganyika: eight new species of Cichlidogyrus Paperna, 1960 (Monogenea: Dactylogyridae) from the northern basin of the lake, with remarks on the vagina and the heel of the male copulatory organ

Abstract

BackgroundLake Tanganyika harbours the most diverse cichlid assemblage of the Great African Lakes. Considering its cichlid flocks consist of approximately 250 endemic species, we can hypothesize a high species-richness in their often quite host-specific monogenean ectoparasites belonging to Cichlidogyrus Paperna, 1960. Yet, only 24 species were described from Tanganyikan hosts and some host tribes have never been investigated for monogeneans. This study presents the first parasitological examination of species of the tribes Cyprichromini (Cyprichromis microlepidotus (Poll, 1956)), Eretmodini (Eretmodus marksmithi Burgess, 2012 and Tanganicodus irsacae Poll, 1950) and Ectodini (Aulonocranus dewindti (Boulenger, 1899)). Specimens of the ectodine Ophthalmotilapia nasuta (Poll & Matthes, 1962) from which four Cichlidogyrus spp. have been previously described from more southern localities were also studied. Further, we discuss the haptor configuration in Tanganyikan Cichlidogyrus spp. and highlight the morphological diversity of the vagina, and that of the heel, a sclerotized part of the male copulatory organ, absent in some species of Cichlidogyrus.Methods Cichlidogyrus spp. were isolated from gills and fixed using GAP. Haptoral and genital hard parts were measured and drawn by means of a phase contrast microscopic examination.ResultsWe describe eight new species: Cichlidogyrus milangelnari n. sp. on C. microlepidotus; C. jeanloujustinei n. sp. on E. marksmithi; C. evikae n. sp. on T. irsacae; C. aspiralis n. sp., C. glacicremoratus n. sp. and C. rectangulus n. sp. on O. nasuta; and C. pseudoaspiralis n. sp. and C. discophonum n. sp. on A. dewindti. Three haptoral morphotypes were recognized among the new species. Species of Cichlidogyrus from closely related hosts exhibited the same morphotypes. Geographical variation in Cichlidogyrus spp. fauna as observed in O. nasuta and three morphotypes were distinguished. Finally, we listed 111 Cichlidogyrus species, of which 27 and three Tanganyikan species lack sclerotized vagina and heel, respectively, just like 19 and seven species outside of the lake.ConclusionsHaptoral and genital features in the Tanganyikan Cichlidogyrus fauna reflect the phylogenetic relationships of their cichlid hosts. It seems that several lineages of Cichlidogyrus spp. exist in Lake Tanganyika but further studies are necessary to confirm this hypothesis and answer questions related to Lake Tanganyika and its cichlids.Electronic supplementary materialThe online version of this article (10.1186/s13071-017-2460-6) contains supplementary material, which is available to authorized users.

Seven new species ofCichlidogyrusPaperna, 1960 (Monogenea: Dactylogyridae) parasitizing the gills of Congolese cichlids from northern Lake Tanganyika

“…nov. as it shares the small size of all hook pairs. The new species most closely resembles C. discophonum described from A. dewindti (see Rahmouni, Vanhove & Šimková, 2017 ) regarding the morphology of the dorsal and ventral anchors and the absence of a heel. However, it differs from the latter by (i) the longer copulatory duct (59–65 μm in C. koblmuelleri sp.…”

“…nov. are small hollow outgrowths on the anterior face, a feature observed in congeners infecting representatives of Tylochromini and Ectodini. With this morphology, we find Tanganyikan C. mulimbwai and C. muzumanii , both from T. polylepis ( Muterezi Bukinga et al, 2012 ), C. pseudoaspiralis from A. dewindti , and C. aspiralis from O. nasuta ( Rahmouni, Vanhove & Šimková, 2017 ) to be just like non-Tanganyikan C. chrysopiformis , C. djietoi , and C. sigmocirrus Pariselle, Bitja Nyom & Bilong Bilong, 2014, all parasites of T. sudanensis Daget, 1954 ( Pariselle, Bitja Nyom & Bilong Bilong, 2014 ), C. kothiasi Pariselle & Euzet, 1994 from T. jentinki (Steindachner, 1862) ( Pariselle & Euzet, 1994 ), and C. dageti , C. euzeti , and C. falcifer Dossou & Birgi, 1984 from Hemichromis fasciatus ( Dossou & Birgi, 1984 ; Pariselle & Euzet, 2009 ). In addition to its haptoral features, C. habluetzeli sp.…”

“…In addition to its haptoral features, C. habluetzeli sp. nov. exhibits a similar morphotype of the reproductive organs as C. aspiralis , C. pseudoaspiralis ( Rahmouni, Vanhove & Šimková, 2017 ), C. casuarinus Pariselle, Muterezi Bukinga & Vanhove, 2015 isolated from a range of cichlid representatives of the tribe Bathybatini Poll, 1986 ( Pariselle et al, 2015a ), C. centesimus ( Vanhove, Volckaert & Pariselle, 2011 ), and C. nshomboi Muterezi Bukinga et al, 2012 from Boulengerochromis microlepis (Boulenger, 1899) Boulengerochromini Takahashi, 2003 (all Tanganyikan species) ( Muterezi Bukinga et al, 2012 ). C. habluetzeli sp.…”

“…nov. vs 12–15 μm in C. sturmbaueri ), (iii) the different hook pairs ( C. adkoningsi sp. nov. exhibits short hook pairs I–IV, VI, and VII while C. sturmbaueri displays short hook pair I and long pairs II–IV, VI, and VII (see Pariselle & Euzet, 2009 ; Rahmouni, Vanhove & Šimková, 2017 for the importance of hook length in the systematics of Cichlidogyrus ), and (iv) the accessory piece (C-shaped, thick in the middle part ending in hook in C. adkoningsi sp. nov. vs H-shaped in C. sturmbaueri ).…”

“…The long auricles of C. adkoningsi sp. nov. are reminiscent of C. vandekerkhovei from O. ventralis , O. boops and O. nasuta , C. glacicremoratus from O. nasuta , and C. discophonum from A. dewindti , which are all parasites of ectodine cichlids ( Vanhove, Volckaert & Pariselle, 2011 ; Rahmouni, Vanhove & Šimková, 2017 ). Further, C. adkoningsi sp.…”