Introduction

The boarfish Capros aper, Linnaeus, 1758 is a small demersal and pelagic fish, unique in its genus, belonging to the Caproidae family [1], with a broad Atlanto-Mediterranean distribution [2]. Capros aper plays a crucial role in the marine ecosystem as a food source for numerous predators [3]. However, this species is less known due to limited biological studies especially in the Mediterranean [4]. Few studies have been conducted on the parasite fauna of Capros aper, particularly on Monogeneans. Therefore, only limited references of these parasites can be found in the literature [5–6].

Monogeneans Platyhelminthes are considered as one of the most host-specific groups of fish parasites, often infecting only a single species or closely related species [7]. Among the oldest Monogeneans genera, Microcotyle (Beneden & Hesse, 1863) includes various species, which are all parasites of marine fishes with a wide distribution [8]. The great resemblance between Microcotyle spp. has posed a big challenge for the identification of different species based on their morphological characters [9]. Therefore, several species have been revised carefully and transferred to other genera [10]. Recently more than 72 valid species have been identified from different fish orders; particularly those belonging to the order of Eupercaria and Perciformes [11].

In the Mediterranean Sea, numerous species of Microcotyle spp. were described based on morphological and molecular analysis [9, 12,13,14,15,16]. Furthermore, a total of four valid new species of Microcotyle have been recorded from the Algerian coast in the Western Mediterranean Sea: Microcotyle algeriensis Ayadi, Justine, Gey & Tazerouti, 2017 from Scorpaena notata Rafinesque, 1810; M. visa Bouguerche, Gey, Justine & Tazerouti, 2019 from Pagrus caeruleostictus (Valenciennes, 1830); M. isyebi Bouguerche, Gey, Justine& Tazerouti, 2019 from Boops boops (Linnaeus, 1758) and M. justinei Ayadi & Tazerouti, 2023 from Apogon imberbis (Linnaeus, 1758).

During a parasitological survey of monogeneans parasites of marine fishes off the Algerian coast in the Western Mediterranean we collected a new species of Microcotyle from the gills and operculum of the boarfish Capros aper. The status of the new species was confirmed by a morphological and molecular study using cytochrome c oxidase subunit 1 (cox1) gene.

Materials and Methods

Fish

Between March 2023 and March 2024, a total of 1428 boarfish Capros aper were captured from two locations off the Algerian coast in the Western Mediterranean: Bouharoun (36°37’ 32” N, 2° 39’ 13” E) and Cap Djinet (36°52’25” N, 3°42’53” E). Specimens were rapidly transferred on ice to the laboratory and identified based on [17]. They were measured and examined fresh in the day of acquisition. The operculum was opened, revealing the gills, which were carefully removed and placed in Petri dishes filled of water. They were then observed using a dissecting microscope.

Morphological Methods

Monogeneans were observed alive or recently dead on the operculum and gills using a dissecting microscope. These parasites were carefully removed and temporarily stored in dishes filled of water. To prepare the specimens for further examination, they were placed in 70% ethanol, stained with acetic carmine, and subjected to a series of ethanol washes (70, 96, and 100%). After being cleared with clove oil, the parasites were ultimately mounted in Canada balsam. Some specimens also mounted in Berlese fluid to study the morphology of sclerotized organs. Drawings were obtained using an Axioskop 50 microscope (Carl Zeiss) equipped with a drawing tube and were scanned and redrawn with Adobe Illustrator CS5. All measurements are expressed in micrometers (µm), and are indicated as the mean followed by the range ± standard deviation and the number of specimens measured in parentheses.

Molecular Methods

To ensure that hosts and monogeneans were labelled with respect of host-parasites relationships, we extracted two specimens of the new species and a tissue sample of the fish’s gills in which the parasites were found. The monogeneans were divided carefully into two parts: the anterior part which includes the sclerotized reproductive organ was used for morphological study and the posterior part which includes the haptor was kept for molecular study.

Molecular Identification of Fish

Total genomic DNA was extracted using QIAamp DNA Mini Kit (Qiagen) according to the manufacturer’s instructions. The 5′ region of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was amplified with the primers TelF1 5’ TCGACTAATCAYAAAGAYATYGGCAC 3’and TelR1 5′ACTTCTGGGTGNCCAAARAATCARAA 3′. PCR reactions were performed in a total volume of 25µL, containing 1µL of DNA, 1µL of TelF1, 1µL of TelR1, 12,5µL MasterMix (2X) and 9,5µL H2O. The amplifcation conditions were as follows: 2 min at 95 °C, followed by 40 cycles at 95 °C for 30 s, 52 °C for 30 s, and 72 °C for1 min, with a final extension step at 72 °C for 10 min. PCR products were sequenced in both directions on a 3730xl DNA Analyzer96–106 capillary sequencer (Applied Biosystems). Codon-Code Aligner version 3.7.1 software 107 (CodonCode Cor-poration, Dedham, MA, USA) was used to edit the sequences. The sequences were compared to the GenBank database with BLAST and deposited in GenBank under the accession number PQ323360 and PQ323380. Species identification was confirmed with the BOLD identification engine.

Monogenean cox1 Sequences

Total genomic DNA was isolated using QIAmp DNA MicroKit (Qiagen). The 5′region of the mitochondrial cytochrome c oxidase was amplified with the primers ASmit1 (for-ward: 5′-TTT TTT GGG CAT CCT GAG GTT TAT-3′) and ASmit2 (reverse: 5′-TAA AGA AAG AACATA ATG AAA ATG-3′) [18, 19]. PCR reactions were performed in 25 µl, containing 3µL of DNA, 0,5µL of Asmit1, 0,5µL of Asmit2, 12,5µL MasterMix (2X), 1,5µL MgCl2 and 7µL H2O. The thermo- cycling profile consisted of an initial denaturation step at 95 °C for 2 min, followed by 40 cycles of denaturation at 95 °C for 30 s, annealing at 47,5 °C for 30 s, and extension at 72 °C for 45 s; the final extension step was conducted at72°C for 10 min. The sequences were edited with Codon Code Aligner software version 3.7.1 (Codon Code Corporation, Dedham, MA, USA), compared to the GenBank database content with BLAST, and deposited in GenBank under the accession number PQ331154-PQ331155.

Molecular Analysis

The new cox1 sequences were aligned together with representative sequences for Microcotyle spp. available on GenBank (Table 1); a sequence of Kuhnia scombercolias Gmelin, 1789 was used as the outgroup. The trees were inferred using neighbour-joining (NJ) and maximum likelihood (ML) methods using MEGA version11 [20]. For this latter, the best-fitting model of nucleotide substitution estimated in MEGA 11 was the Tamura-Nei model with gamma distributed among-site variation and a proportion of invariant sites (TN93 + G + I). All codon positions were included in the analyses. Bootstrap support was based on 1000 replicate trees in both analyses. Genetic distances (uncorrected p-distance model) were calculated in MEGA 11.

Table 1 Species of Microcotyle used in the phylogenetic analyses
Full size table

Results

Molecular Identification of Fish

The identification of fish species using morphological characteristics was supported by DNA barcoding approach. BLAST analysis of the cox1 sequences of our fish specimens with NCBI and BOLD database showed sequences similarity values of 100% to Capros aper.

Molecular Identification of Monogeneans

The two newly generated cox1 sequences were analysed with 24 sequences of Microcotyle spp. and there was a total of 396 nucleotide positions in the final dataset. Phylogenetic analyses shows that the neighbor joining (NJ) and maximum likelihood (ML) had the same topologies, so only the Ml tree is provided in Fig. 1. The two sequences of M. tazeroutii n. sp. grouped together as a robust clade with 100% boostrap support in ML and clustered together with Microcotyle isyebi Bouguerche, Gey, Justine & Tazerouti, 2019 from Boops boops Linnaeus, 1758 off Algeria and Spain. Two other clades with high supported boostrap in ML and NJ analyses were recovered in the cox 1 phylogeny. The first clade (73% ML and 71% NJ) was formed by species of Microcotyle collected from sebastid fishes (Sebastidae Kaup, 1873): (i) M. sebastis Goto, 1894 from Sebastes schlegelii Hilgendorf, 1880 off Korea; (ii) M. pacinkar Kamio & Nitta, 2023 from Sebastes taczanowskii Steindachner, 1880 off Japan (iii) M. caudata Goto, 1894 from Sebastes inermis Cuvier, 1829 off Japan; and (iv) M. kasago Ono, Matsumoto, Nitta & Kamio, 2020 from Sebastiscus marmoratus (Cuvier, 1829) off Japan. The second clade (bootstrap support of 99% (NJ) and 99% (ML)) was formed by species of Microcotyle from scorpaenid fishes (Scorpaenidae Risso, 1827): (i) M. algeriensis from Scorpaena notata off Algeria; (ii) Microcotyle sp. from Helicolenus dactylopterus Delaroche, 1809 off Algeria; and (iii) M. merche Víllora-Montero, Pérez-del-Olmo, Valmaseda-Angulo, Raga & Montero, 2023 from H. dactylopterus off Spain.

Fig. 1
figure 1

Molecular phylogenetic analysis using maximum likelihood (ML) method. Bootstrap support values are shown at the nodes as ML/NJ (only values > 70% are represented). The analysis is done with 24 nucleotides sequences with a total of 396 positions in the final dataset. Kuhnia_scombercolias was used as the out-group

Full size image

Distances were computed using p-distance and are represented in Table 2. The two sequences of M. tazeroutii n. sp. were identical. The distance between these sequences and other sequences of Microcotyle ranged between 8.59 and 15.91%.

Table 2 Distance between Microcotyle Spp. The divergence distance was calculated with p-distance method and it is shown as a percentage
Full size table

The sequences for M. tazeroutii differed from three sequences for Microcotyle isyebi from Boops boops off Algeria and Spain (Mediterranean) by 8.59–9.34%; from two sequences for M. visa from Pagrus caeruleostictus Valenciennes, 1830 off Algeria (Mediterranean) by 9.34–9.85%; from Microcotyle sp. and M. merche from Helicolenus dactylopterus off Algeria and Spain respectively (Mediterranean) by13.89%. M. tazeroutii also differed from M. justinei from Apogon imberbis Linnaeus, 1758 off Algeria by 14.09%; from M. erythrini Van Beneden & Hesse, 1863 from Boops boops off Spain (Mediterranean) by 15.15–15.40%; from M. algeriensis from Scorpaena notata off Algeria (Mediterranean) by 15.66% and from M. whittingtoni Víllora‑Montero, Pérez‑del‑Olmo, Georgieva, Raga & Montero, 2020 from Dentex dentex off Spain (Mediterranean) by 15.66–15.91%.

Taxonomic Summary

Family: Microcotylidae Taschenberg, 1879.

Subfamily: Microcotylinae Taschenberg, 1879.

Genus: Microcotyle van Beneden and Hesse, 1863.

Microcotyle tazeroutii n. sp.

Type-host: Capros aper (Teleostei: Caproidae) identification of fish specimens confirmed by molecular barcoding.

Type-locality: Bouharoun (36°37’ 32” N, 2° 39’ 13” E) off Algiers, Algeria, Western Mediterranean.

Other localities: Cap Djinet (36°52’25” N, 3°42’53”), off Algiers, Algeria.

Microhabitat: Operculum and Gills.

Material examined: 1428 specimens.

Prevalence: 4, 55% (65/1428).

Type-material: Holotype MNHN HEL2090, paratypes MNHN HEL2091-MNHN HEL2098, including two molecular vouchers, are deposited in the collections of the Muséum National d’Histoire Naturelle, Paris (MNHN). Paratypes (sequenced): anterior part of the specimen mounted on slide, posterior part used for molecular analysis: specimen Caap1 Mo1- Caap2 Mo1, slide MNHN HEL2099-MNHN HEL3000.

Representative DNA sequences: New species: GenBank PQ331154-PQ331155 (paratype: Caap1 Mo1, MNHN HEL2099; Caap2 Mo1, MNHN HEL3000); fish host species: GenBank PQ323360-PQ323380.

Etymology: The newly discovered species is given the honorary name of Professor TAZEROUTI Fadila from the University of Science and Technology Houari Boumediene, an expert biologist in Helminth parasites. Professor TAZEROUTI Fadila has inspired and influenced lot of biologists and parasitologists over the years.

Description

We conducted measurements and morphological analysis on 15 specimens, which were stained with acetic carmine and mounted on permanent slides in Canada balsam (Fig. 2).

Fig. 2
figure 2

Microcotyle tazroutii n. sp. ex Capros aper from Algeria; a whole body, holotype; b clamps, holotype; c spines of genital atrium, holotype; d detail of germarium, paratype; e egg, paratype

Full size image

Body fusiform, elongated and flattened dorsoventrally, 1868 ± 410 (1364–2625, n = 15) long and 110 ± 20 (86–138, n = 15) width at level of suckers, 177 ± 37 (136–250, n = 15) width at level of genital atrium, 484 ± 133 (273–688, n = 15) width at level of germarium (maximum width), and 454 ± 126 (245–637, n = 15) width at level of testes. Haptor elongate, sub-symmetrical and continuous with body, 462 ± 103 (318–714, n = 15) long, with 45 ± 4 (38–52, n = 15) clamps of “microcotylid” type arranged in 2 sub-equal lateral rows; clamps 35 ± 6 (27–46, n = 15) in length and 62 ± 6 (51–69,1, n = 15) in width, the most posterior slightly smaller than others, 29 ± 3 (21–34, n = 15) in length, 43 ± 5 (32–53, n = 15) in width. “C” sclerite maximum width 5 ± 1 (3–7, n = 15).

The oral opening is elliptical with two oval, buccal suckers, septate, ventrally oriented with 37 ± 9 (21–55, n = 15) in length and 38 ± 10 (20–55, n = 15) in width. Pharynx muscular, globular, 56 ± 11 (40–82, n = 15) long, 45 ± 8 (32–56, n = 15) width, mostly overlapping buccal suckers. Oesophagus short 184 ± 53 (136–300, n = 15) in length, bifurcates at the end of the posterior part of the genital atrium, into two caeca laterally ramified, mostly not united posteriorly. Right caecum extends into haptor for a short distance, left caecum ends near the beginning of haptor.

Testes post-ovarian and pre-haptoral, intercaecal, 10 ± 1,3 (8–13, n = 15) in number with oval to irregular shape, 57 ± 10,2 (38–76, n = 15) in length, 64 ± 12 (46–83, n = 15) in width, arranged into 1 or 2 rows. Testicular field at 1129 ± 269,2 (727–1613, n = 15) from anterior extremity of the body. Maximum testes area 335 ± 129,3 (182–625, n = 15) in length, 145 ± 74,4 (71–350, n = 15) in width. Vas deferens dorsal to uterus, opening to genital atrium. Genital atrium shaped as a triangle with rounded corners 91 ± 34,4 (58–150, n = 15) in length, 108 ± 24,6 (62–143,8, n = 15) in width and at 167 ± 44,2 (109–250, n = 15) from anterior extremity of body; armed with numerous spines arranged into a main group and two posterior small lateral groups (‘pockets’ of Mamaev [21]); number of spines in main group 111 ± 13,2 (96–136, n = 9), 8 ± 0,9 (6–9, n = 9) in length; the two posterior small lateral chamber armed with spines 13 ± 3 (10– 20, n = 15) in number with 4 ± 0,6 (3–5, n = 14) in length.

Vaginal pore unarmed, medio-dorsal, posterior to genital atrium, distance from vagina to anterior end extremity 287 ± 65,2 (191–400, n = 15). Germarium, pre-testicular, question mark-shaped, 220 ± 38,6 (127–281, n = 15) in length, 164 ± 40 (109–231, n = 15) in width, at 914 ± 252 (546–1338, n = 12) from anterior end distance. Oviduct a long tube ending posteriorly in oötype marked by Mehlis Glands, connected with elongated seminal receptacle 102 ± 27,1 (64–138, n = 14) in length, 37 ± 9,1 (20–54, n = 14) in width. Genito-intestinal canal rarely observed, connect oviduct ventrally into intestinal caecum. Uterus wide, ascending straight up to the genital atrium. Vitellarium located laterally in both sides of the body, at 316 ± 78,5 (209–475, n = 15) from anterior extremity, begins from level of intestinal caeca, coextensive with intestinal branches, surrounding the testes and reaching up to haptor region. Posterior extremities of vitelline fields mostly separated, 33 ± 27,7 (0–90,6, n = 15). Vitelline ducts at the middle of the body, with Y-shaped structure with two separated ducts; left efferent duct 157 ± 66,4 (55– 251, n = 15) long, right efferent duct 137 ± 64,8 (27–266, n = 15) long. Eggs fusiform, 204 ± 27,2 (159–245, n = 15) long, 48 ± 12,1 (32–72, n = 15) wide, with two filament in each side opercular filament long and thin, abopercular filament short, 99 ± 17,4 (75–128, n = 15) long.

Remarks

Molecular Distinction

Intraspecific differences of cox1 sequences reported from several Monogenea Polyopisthocotylea are between 0.2 and 5.6% [12–13]; while interspecific differences ranging 4–15,7 have been reported from species of the genus Microcotyle [12,13,14,15,16, 22]; The interspecific differences between Microcotyle tazeroutii n. sp. and sequences of Microcotyle spp. available on GenBank ranged between 8,59 and 15,91. Therefore, the new species reveal a clear divergence from all previously published sequences of Microcotyle.

Differential Diagnosis

In the following section, we compare Microcotyle tazeroutii n. sp. with other species of Microcotyle previously recorded from the same type locality and phylogenetically closed species (Table 3).

Table 3 Comparative data for Microcotyle tazeroutii n. sp. and Microcotyle spp. originally described off Western Mediterranean
Full size table

Microcotyle tazeroutii n. sp. share the same type-locality as M. isyebi described from Boops boops off Bouharoun (Algeria). The two species resemble in the arrangement of the spines and the size of the genital atrium (58–150 × 62–144 vs 65–170 × 45–120) and the size of eggs without filaments (159–245 × 32–72 vs 125–260 × 45–95). M. tazeroutii n. sp. and M. isyebi differ in haptor length (318–714 vs 500–1250), number of clamps (38–52 vs 54–102), the distance between the vagina to anterior extremity (191–401 vs 410–700), the number of testes (8–13 vs 13–29) and the number of spines in the main part of genital atrium (96–136 vs 136–230).

Microcotyle tazeroutii n. sp. has the same type-locality as M. algeriensis described from Scorpaena notata off Bouharoun (Algeria). These species also resemble in testes number (8–13 vs 9–20) and the size of eggs without filaments (159–245 × 32–72 vs 215–257 × 50–85). However, M. tazeroutii differs from M. algeriensis by the number of clamps (38–52 vs 20–39), the length of anterior clamp (27–46 vs 48–85) and the number of spines of the main part of genital atrium (96 − 136 vs 68–162).

Microcotyle tazeroutii n. sp. exhibits morphological similarities to M. visa from Pagrus caeruleosticus off Zemmouri El Bahri (Algeria) in the length of the anterior clamps ( 27–46 vs 25–60), buccal organ width ( 20 − 55 vs 20–60) and the eggs length ( 159–245 vs 157–260), but it differs by the haptor length (318–714 vs 250–1,250), the clamps number (38–52 vs 59–126), the number of spines of the main part of genital atrium ( 96 − 136 vs 142–224), the total number of spines in pockets (10–20 vs 18–39), the distance from vagina to anterior extremity (191–401 vs 320–780) and the number of testes (8–13 vs 14–29).

Microcotyle tazeroutii n. sp. resembles Microcotyle justinei described from Apogon imberbis off Bordj El Kiffan and Cap Djinet (Algeria), in number of clamps (38–52 vs 47–66), the oesophagus length ( 136–300 vs 185–321), the size and general shape of the genital atrium (109–250 × 58–150 vs 65–136 × 48–131), the length of spines in the main chamber of the genital atrium (6–9 vs 5–8) and the size and the general shape of testes (38–76 × 46– 83 vs 47–88 × 45–89). However, M. tazeroutii n. sp. can be differentiated from M. justinei by the haptor length (318–714 vs 580–1019), the number of spines of the main part of genital atrium (96 − 136 vs 145–203) and the number of testes (8–13 vs 17–22).

Microcotyle tazeroutii n. sp. shares several morphological and morphometrical traits with M. merche from Helicolenus dactylopterus off Bay of Biscay (Spain), such as the clamps number (38–52 vs 42–58), the anterior clamps size (27– 46 × 51–69 vs 27–45 × 52–78), the width of sclerite ‘c’ (3–7 vs 4–7) and the number of testes (8–13 vs 13–18). The two species differ in the size of seminal receptacle (64–138 × 20–54 vs 55.0–532.6 × 56.1–620.1), the size and general shape of testes (38–76 × 46–83 vs 48.6–126.5 × 43.7–147.9), the length of spines in the main chamber of the genital atrium (96–136 vs 146–221) and the distance between vitellarium in posterior extremity (0–91 vs 0.0–204.8).

Microcotyle tazeroutii n. sp. resembles M. whittingtoni from Dentex dentex off Guardamar del Segura (Spain) in the haptor length ( 318 − 714 vs 862–1264), the size of the anterior clamps (27– 46 × 51–69 vs 22–47 × 52–75), the sclerite ‘c’ width (3– 7 vs 3–6) and the shape and the size of eggs (159– 245 × 32 − 72 vs 184–264 × 66–84). The two species are distinguished by the number of spines of the main part of genital atrium ( 96–136 vs 272–391), the length of spines in the main chamber of the genital atrium (6–9 vs 4–7), the total number of spines in pockets (10–20 vs 34–47), the size of germarium (127–281 × 109–231 vs 730–1199 × 38–86), the distance between vitellarium in the posterior region (0–91 vs 129–498) and the number of testes (8–13, vs 16–27).

Other species that are geographically and phylogenetically distant from Microcotyle tazeroutii n. sp. such as: Microcotyle erythrini, M. sebastis, M. pacinkar, M. caudata, M. kasago and M. bassensis revealed several morphological differences with the new species.

Discussion

This study allowed us to understand more about Monogeneans ectoparasites of Capros aper, which is the only species within the genus capros (Linnaeus, 1758), present in the Algerian coast in the Western Mediterranean Sea. In literature, the metazoan fauna of this fish is repeatedly studied and this revealed the presence of Trematoda digeneans and copepods [5, 23]. Furthermore, there is only one Monogenean Monopisthocotylean (Odhner, 1912) Paradiplectanotrema trachuri Kovaleva, 1970 which is reported from Capros aper [6]. Generally, the diversity of parasites species is influenced by both the physical and chemical factors of the microhabitat [24] as well as zoogeographical factors [25, 26]. Among Monogeneans Polyopisthocotylea, the genus Microcotyle is reported from different hosts of unrelated taxon [15, 27], among which 13.4% have been reported from Eupercaria, 7.5% from the Perciformes order and 3% from sebastids and from Scorpaenids [12, 22]. In addition Microcotyle spp. were recorded from several localities, such as the Atlantic Ocean [28,29,30], the Pacific [31,32,33,34], the Arabian Sea [08] and the Mediterranean Sea [9, 12–13, 16, 35, 36, 37, 38, 39], According to [14], the morphological differentiation between the species of the genus remains difficult because of the great resemblance of the metrical features based on criteria given by earliest description such as measurement of soft body parts, body and eggs size and the number of clamps and testes. Some characteristics, like body width, number of clamps, and eggs size, can be influenced by the age of the parasite [40]. The revision of specific composition of the genus can be hardly accomplished without reexamination of the type material. Different studies on Microcotyle spp. showed that some species present a great morphological resemblance, such as: (i) M. erythrini Van Beneden & Hesse (1863) from Pagellus erythrinus Linnaeus, 1758 and M. isyebi Bouguerche, Gey, Justine & Tazerouti, 2019 from Boops boops Linnaeus, 1758, (ii) M. caudata Goto, 1894 and M. merche Víllora-Montero, Pérez-del-Olmo, Valmaseda-Angulo, Raga & Montero, 2023 from Sebastes inermis Cuvier, 1829 and Helicolenus dactylopterus Delaroche, 1809 respectively [15], (iii) M. pomatomi Goto, 1899 from Pomatomus saltatrix Linnaeus, 1766 and M. erythrini from Pagellus erythrinus Linnaeus, 1758 [41].

In their description of M. omanae Machkewskyi, Dmitrieva, Al-Jufaili & Al-Mazrooei, 2013 [8], used statistical methods to estimate measurements variability and dependence on body size. According to [14], only completely mature adults should be representative and selected in the morphologic study for standardized taxonomic descriptions. In immature adults, testes are early functional and vas deferens is full of sperm while no developed oocytes exist in the germarium. Thus, new morphometrical parameters are used to differentiate between Microcotyle spp., such as: (i) Body width at different levels, (ii) Sclerite “C” width, (iii) distance between organs and anterior extremity and (iv) Length of vitellarium within haptor and into posterior limbs. In the most recent studies on Microcotyle spp., the morphological approach is supported by molecules such as 28 S and cox1 gene [42]. This latter, becomes the mostly used for understanding phylogenetic relationship and geographical distribution of Microcotyle spp. and their hosts [34].

To conclude, we describe for the first time a new monogenean parasite, Microcotyle tazeroutii n. sp. from the Caproidae (Bonaparte, 1835) Capros aper off the Algerian coast in the Western Mediterranean Sea. This parasite is morphologically and molecularly distinct from all previously identified Microcotyle species.