Species of Gyrodactylus von Nordmann, 1832 (Platyhelminthes: Monogenea) from cichlids from Zambezi and Limpopo river basins in Zimbabwe and South Africa: evidence for unexplored species richness

Abstract

New findings on Gyrodactylus spp. parasitising African cichlids in southern Africa are presented, comprising data from Zimbabwe and South Africa. Morphometry of opisthaptoral hard parts in combination with nuclear ribosomal DNA sequences confirmed the presence of six species of Gyrodactylus von Nordmann, 1832. Three new species are described from fishes in Zimbabwe: Gyrodactylus chitandiri n. sp. from the gill arches of Coptodon rendalli (Boulenger) and Pseudocrenilabrus philander (Weber); Gyrodactylus occupatus n. sp. from the fins of Oreochromis niloticus (L.), Pharyngochromis acuticeps (Steindachner) and P. philander; and Gyrodactylus parisellei n. sp. from the fins of O. niloticus, P. philander and Tilapia sp. Gyrodactylus nyanzae Paperna, 1973 was also identified from the gills of O. niloticus and C. rendalli collected from two localities in Zimbabwe; these findings represent new host and locality records for this parasite. Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011 was identified from P. philander collected in South Africa and Zimbabwe thereby providing new host and locality records for this parasite. Finally, Gyrodactylus yacatli García-Vásquez, Hansen, Christison, Bron & Shinn, 2011 was collected from the fins of O. niloticus and P. philander studied in Zimbabwe; this represents the first record of this species from the continent of Africa. Notably, this study improves upon the knowledge of Gyrodactylus spp. parasitising cichlids from these southern African regions. All species studied were recorded from at least two different cichlid host species indicating trend for a wide range of Gyrodactylus hosts in Africa. Accordingly, this supports the idea of intensive host switching in the course of their evolution.

The first next-generation sequencing approach to the mitochondrial phylogeny of African monogenean parasites (Platyhelminthes: Gyrodactylidae and Dactylogyridae)

“…These include, respectively, the supergenera Gyrodactylus and Dactylogyrus , some of the most significant radiations of flatworm fish parasites [ 1 ]. Around 500 species of Gyrodactylus have been described at present ([ 3 ] and references therein), but the estimated species number is much higher [ 4 ]. These minute flatworms attach to their host by means of an opisthaptor, often used in monogenean taxonomy [ 5 ].…”

The first next-generation sequencing approach to the mitochondrial phylogeny of African monogenean parasites (Platyhelminthes: Gyrodactylidae and Dactylogyridae)

“…Parasites isolated either in situ or later from preserved fish gills were fixed and preserved in analytical-grade ethanol. Individual monogenean specimens were identified on the basis of their morphology using keys and features described in Pariselle & Euzet (2009), Barson et al (2010) and Zahradníčková et al (2016). Identified specimens were pooled per species in absolute ethanol: four specimens of Macrogyrodactylus karibae (supplemented with two extracts from Barson et al (2010)), 43 of Cichlidogyrus mbirizei , 18 of Cichlidogyrus halli and 44 of Gyrodactylus nyanzae .…”

“…Identified specimens were pooled per species in absolute ethanol: four specimens of Macrogyrodactylus karibae (supplemented with two extracts from Barson et al (2010)), 43 of Cichlidogyrus mbirizei , 18 of Cichlidogyrus halli and 44 of Gyrodactylus nyanzae . While M. karibae is a typical gill parasite of Clarias gariepinus known from southern Africa (Barson et al 2010 and references therein), G. nyanzae and especially C. halli are known from a wide range of cichlids throughout Africa (Pariselle & Euzet 2009; Zahradníčková et al 2016). The two latter species have previously been reported from tilapias in the Haut-Katanga province (Jorissen et al 2017).…”

“…These include, respectively, the supergenera Dactylogyrus and Gyrodactylus , some of the most significant radiations of flatworm fish parasites (Cribb et al, 2002). Around 500 species of Gyrodactylus species have been described at present (Zahradníčková et al 2016 and references therein), but the estimated species number is much higher (Bakke et al, 2002). These minute flatworms attach to their host by means of a characteristic and diagnostic opisthaptor (Paladini et al 2017).…”

“…These fish families are also relatively well-studied for monogenean parasites (e.g. Beletew et al 2016; Zahradníčková et al 2016). They harbour several originally African monogeneans that are widely distributed within and outside Africa, and that are important in the study of parasite ecology, evolution and invasion biology because of the economic and scientific importance of their hosts (Vanhove et al 2016).…”