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The American blue crab, Callinectes sapidus Rathbun, 1896 is native to the western Atlantic. The present work reviews the spread of C. sapidus in the European Atlantic, the Mediterranean, Black Sea and Sea of Azov, and identifies its first occurrence in the Merja Zerga and Khnifiss lagoons on the Moroccan Atlantic coast. These first and southernmost records on the African Atlantic widen the current biogeographic distribution of the species worldwide. Genetic analysis of specimens from both the Mediterranean (Marchica lagoon) and Atlantic (Merja Zerga and Khnifiss lagoons) coasts of Morocco, based on COI (Cytochrome c oxidase subunit I), confirmed the species sequences as being those of Callinectes sapidus. Moroccan populations have low haplotypic diversity with only two haplotypes (haplotype 1 and haplotype 7). These two haplotypes correspond to the two different haplotypes already found in the Mediterranean. Haplotype 1 from Merja Zerga, Marchica and Khnifiss lagoons was 100% identical to the sequences ON248058 in GenBank, while haplotype 7 from the Marchica and Merja Zerga lagoons was 100% identical to the sequences ON248059. Very likely, the origin and pathway of colonisation of the populations established in the three Moroccan lagoons is the result of the expansion of the species along the Mediterranean Sea and now the Atlantic coast of Africa. [ABSTRACT FROM AUTHOR]

In Morocco, no work has been carried out on parasitic monogeneans of cichlid fish as far. An examination of the gills of 375 fish from three native species of Cichlidae: Oreochromis aureus, Coptodon zillii and Coptodon guineensis from different localities, revealed the presence of two monogenean species (1328 monogenean specimens were recovered from 56 fish specimens) belonging to the family Dactylogyridae and to the genus Cichlidogyrus: three morphotypes of C. cirratus were identified from O. aureus and C. zillii; and C. cubitus was identified from C. guineensis. This is the first time that these monogeneans were collected and identified in Morocco. In addition, O. aureus was revealed as a new host for C. cirratus. The low parasite species richness and intensity, appear to support the enemy release hypothesis, and have probably promoted the lateral transfer of parasites in natural populations between O. aureus and C. zillii, and the synxenic diversification of C. cirratus. [ABSTRACT FROM AUTHOR]

Simple Summary: Monogenean flatworms are mainly parasitic in lower aquatic vertebrates including fish, anurans and chelonians. Gyrodactylus is one of the 23 genera of Gyrodactylidae. With only 41 species described, the total number of Gyrodactylus species described from African freshwater fish still remains low. The known species represent only a fraction of the expected species richness of Gyrodactylus in Africa. In this study, we examined the gills of 738 cyprinid specimens. We isolated 26 individuals belonging to Gyrodactylus from these hosts. Twelve of these from two host species were morphologically characterized and proposed to belong to one single newly described species. In view of the importance of the cyprinid–monogenean system in studying the aquatic biodiversity and biogeography of North Africa, the present study is a substantial contribution to the parasite species inventory of these fishes. To date, 41 species of Gyrodactylus have been described from Africa. However, none of these have been reported in Morocco. After identifying and examining 738 cyprinid host specimens, 26 specimens belonging to Gyrodactylus were found to parasitize the gills of nine species of Luciobarbus, Carasobarbus, and Pterocapoeta. The current study provides new information about the presence of a new parasitic species in Morocco, the first to be characterized on a species level in the Maghreb region. It describes in detail 12 specimens of Gyrodactylus isolated from the gills of Luciobarbus pallaryi (Pellegrin, 1919) and Luciobarbus ksibi (Boulenger, 1905). Based on morphoanatomical observations, the characterization of the specimens collected indicates a species of Gyrodactylus that is new to science, described here as Gyrodactylus nyingiae n. sp. The new species is different from previously described gyrodactylids infecting African cyprinid hosts because it has a longer hamulus total length, a longer hamulus root, a downward projecting toe of the marginal hook, and a trapezium-shaped ventral bar membrane with a slightly striated median portion and small rounded anterolateral processes. This study increases the total number of Gyrodactylus spp. found in African cyprinids to four. [ABSTRACT FROM AUTHOR]

Cyprinid fishes are known to harbour highly host-specific gill-associated parasites of Dactylogyrus. High similarity in the morphology of sclerotized structures among Dactylogyrus species, especially those parasitizing congeneric cyprinoids, makes their identification difficult. In this paper, four previously known species of Dactylogyrus are characterized and illustrated under a reliable taxonomic framework integrating morphological and molecular evidence, and their phylogenetic relationships are investigated using molecular data. The species are as follows: D. borjensis from Luciobarbus zayanensis; D. draaensis from Luciobarbus lepineyi; D. ksibii from Luciobarbus ksibi and Luciobarbus rabatensis; and D. marocanus from Carasobarbus fritschii, L. ksibi, L. zaya-nensis and Pterocapoeta maroccana. Our results revealed intraspecific genetic variability among specimens of D. ksibii collected from two different hosts and geographically distant basins. Phylogenetic reconstruction showed that Dactylogyrus spp. parasitizing Moroccan cyprinids are representatives of three main lineages corresponding to morphological differences and host specificity. Our records of D. marocanus on L. zayanensis and P. maroccana increase the range of available host species i.e., eight species of four cyprinid genera representing two phylogenetic lineages (i.e., Barbinae and Torinae). [ABSTRACT FROM AUTHOR]

Two specimens of Coptodon guineensis (Günther, 1862) were unexpectedly found in the Canal de Nador, Moulay Bousselham lagoon, almost 1000 km north of the Aabar River the northernmost river previously recorded. To confirm this identification nineteen measurements were recorded from each specimen and compared with other specimens of C. guineensis from Morocco and Mauritania. The COI gene was partially sequenced and compared with formerly published sequences of Coptodon species of the region. Both morphology and DNA revealed no differences with specimens from known populations of C. guineensis in Morocco. [ABSTRACT FROM AUTHOR]

Gill monogenean species of Ligophorus Euzet et Suriano, 1977 were studied from the teleost Mugil cephalus Linneaus (Mugilidae) from the Mediterranean and Atlantic coasts of Morocco. We report the presence of L. mediterraneus from both the Mediterranean and Atlantic coast and L. cephali and L. maroccanus sp. n. from the Atlantic coast only. The latter species, which is described herein as new, resembles L. guanduensis but differs from this species mainly in having a shorter penis compared to the accessory piece, a proportionally longer extremity of the accessory piece and a less developed heel. The utility of Ligophorus spp. as markers of cryptic species of the complex M. cephalus is discussed in the context of species diversity and geographical distribution of these monogeneans on this host around the world. Presence of different species of Ligophorus on M. cephalus sensu stricto from the Atlantic and Mediterranean coast of Morocco demonstrates the usefulness of these species as fine resolution markers of genetic populations of their host, which are known to inhabit those coasts.

Lamellodiscus dentexi Aljoshkina, 1984, a gill parasite of Dentex macrophthalmus (Bloch), is redescribed based on new material from the northwest coast of Africa (Senegal and Morocco). Three new species of Lamellodiscus Johnston et Tiegs, 1922 from D. macrophthalmus are described, Lamellodiscus toguebayei sp. n., L. vicinus sp. n., and L. triacies sp. n., all belonging to the "ignoratus" group. They can be distinguished from all other species of this group by the size and shape of male copulatory organ and sclerotised parts of the haptor. Considering the peculiar morphology of the male copulatory organ (long and thin tube) we propose to put together L. dentexi, L. virgula Euzet et Oliver, 1967 and L. obeliae Oliver, 1973 to form the "elongatus" type within the "elegans" group.