Clement Pornin

Tan Phu Vuong

Pascal Xavier

Gilbert Angenieux

Shielding effectiveness assessement of a coaxial cable design with a combination of numerical and analytical solutions

Keywords: Coaxial cable, EMC, Transfer impedance, shielding effectiveness, numerical modeling

come

Shielding effectiveness assessement of a coaxial cable design with a combination of numerical and analytical solutions

INTRODUCTION

Development of the industry and telecommunication, in particularly since the past century, rises ever more the density of integration of electronic devices. Insuring signal integrity through transmission lines connecting all these devices becomes a very sensitive task. Electromagnetic compatibility has to be considered at all the steps of design of a device. Coaxial transmission lines are widely used since the beginning of the XX th century in order to insure the signal integrity of transmitted data. The first coaxial line had solid copper shield, which gave very good shielding properties but wasn't flexible. For the sake of the flexibility and the feasibility of the installation process, the braided shield is used in most cases. Nevertheless, the shielding properties of the braided metal is not as good as solid tubes and the assessment of a new design is hard to process. Many researchers tried to define analytical solutions in order to directly obtain the shielding properties of a cable from the building parameters of the braided shield. The most interesting papers in this field will be slightly reviewed in the first section. Each of these works had brought useful elements on the way to the exact theory to predict the behavior of the braided shields against external spurious signals but always kept some discrepancies with the reality of the measurement. On the other hand, numerical electromagnetic modeling of coaxial cables have been more recently introduced by fewer authors and appears to be promising. Some of these works will be slightly reviewed in the second section.

Organization of the paper: This paper has four parts.

-The first part is a brief review of previous works on the theory of the coaxial cable shields. -The second part introduces some numerical electromagnetic models built by other authors. -The third part gives our numerical model and and its peering with analytical solutions. -The fourth part contains the results obtained, compared with other measurement and theory and gives the conclusions.

I. THEORIES ON COAXIAL CABLE SHIELDS

A. The first approach brought by Schelkunoff

The first research on coaxial transmission lines shielding effectiveness was brought by Schelkunoff [START_REF] Schelkunoff | The Electromagnetic Theory of Coaxial Transmission Lines and Cylindrical Shields[END_REF] in 1934. His work was focused on coaxial transmission lines with a solid copper tube as a shield. These transmission lines where used in radar installations. He gave a lot of theoretical analysis to understand the behavior of these cables against ElectroMagnetic Interferences (EMI). He defined the notion of transfer impedance (Z t [Ω.m -1 ] ), which is intrinsic to the cable itself. This parameter is calculated using equation [START_REF] Schelkunoff | The Electromagnetic Theory of Coaxial Transmission Lines and Cylindrical Shields[END_REF], with reference to the measurement setup depicted in figure 1.

Z t = ΔV I s × L [Ω.m -1 ] (1)
Where ΔV [V] is the potential difference between the shield and the cable core appearing at one end of the cable when a current I s [A] flows on the shield of the cable under test (CUT). L [m] is the length of the sample of cable. One end of the cable is in short circuit and the other end is connected to the high input impedance of the tension measurement device. The transfer impedance parameter illustrates the coupling between the external magnetic wave associated to the shield current I s with the transverse electromagnetic (TEM) wave propagating inside the cable. The purpose of the shield is to obtain the lowest value of transfer impedance, in order to minimize this coupling.

{clement.pornin, tan-phu.vuong, pascal.xavier1}@grenoble-inp.fr, gilbert.angenieux@univ-smb.fr *

I. I

978-1-7281-0594-9/19/$31.00 © 2019 IEEE

B. Theorical studies on the braided shields

Vance [START_REF] Vance | Shielding Effectiveness of Braided-Wire Shields[END_REF] used the theory brought by Kaden [START_REF] Kaden | Wirbelströme und Schirmung in der Nachrichtentechnik[END_REF] and Marcuvitz [START_REF] Marcuvitz | Waveguide Handbook[END_REF] , who studied the leakage of electromagnetic waves through perforated metallic tubes. His purpose was to model the coupling through holes appearing in the braid as shown in figure 2. Vance said that the magnetic coupling through the holes, as shown in figure 3, can be modeled as an inductive term M 12 in the expression of Z t of the equation 5. The inductive coupling through hole is socalled the hole inductance. Other authors made improvements of Vance's model. For exemple Kley's semi empirical description in [START_REF] Kley | Optimized single-braided cable shields[END_REF] and Sali [START_REF] Sali | An improved model for the transfer impedance calculations of braided coaxial cables[END_REF]. For the sake of simplicity, we here took as a reference the recently published paper [START_REF] Verpoorte | Advanced models for the transfer impedance of metal braids in cable harnesses[END_REF] describing the behaviour of braided shield against EMI. This paper presents a reliable review of existing models in order to enable the reader to choose the most relevant model for the considered cable. Fig. 2. representation of the braided structure with main building parameters [START_REF] David | Simulation of cable coupling Final Report[END_REF] The building parameters of the braid are :

-n number of strands in a spindle ζ the number of spindles -d the diameter of elementary conductors of the braid [m] -D the diameter of the shield σ the conductivity of the braid's metal [S.m -1 ] -α the angle between braid conductors and the axis of the cable -the angle between two crossing strands is 2α

In [START_REF] Vance | Shielding Effectiveness of Braided-Wire Shields[END_REF], Vance linked these primary parameters with secondary parameters: the dimensionless filling factor F(equation 2), the number of carrier crossings and holes per unit length, respectively P (equation 3) and ν (equation 4).

F = nζd 4πD cosα [φ] (2)
P = ζ sinα 4πD cosα = ζ 4πD tanα [m -1 ] (3)
ν = P ζ = 4π D sinα cosα n 2 d 2 F 2 [m -1 ] (4)
Z t = R 0 × γ∂ sh(γ∂) + jωM 12 [Ω.m -1 ] (5)
Where R 0 [Ω] is the DC resistance of the braid calculated with equation 6 and ∂ = d/δ; where δ is the skin depth defined by equation 7. The term γ∂ sh(γ∂) corresponds to the diffusion of electromagnetic field through the thickness of the metal braid. The diffusion term dominates the transfer impedance at low frequency. γ = 1 + j is the complex propagation constant in the shield according to [START_REF] Vance | Shielding effectiveness of braided wire shields, interraction note[END_REF].

R 0 = 4 n ζ σ cosα d 2 [Ω.m -1 ] (6) δ = 1 √ πf μσ [m] ( 7
)
Where μ is the magnetic permeability of the braid metal [H.m -1 ] and f [Hz] the considered frequency.

The mutual inductance term of Vance's model in [START_REF] Vance | Shielding Effectiveness of Braided-Wire Shields[END_REF]is only based on the hole inductance and is defined by equation 8.

M 12 V ance = ν μ 0 m 4π 2 D 2 [H] ( 8
)
Where m is the magnetic polarizability of the rhombic shape of the hole given in an improved form in [START_REF] Smedt | Magnetic polarizability of some small apertures[END_REF] [START_REF] De Meulenaere | Polarizability of some small apertures[END_REF]. In [START_REF] Schippers | Hole inductance in braided cable shields[END_REF], the authors widely reviewed the notion of hole inductance and gave the equation 9 to approximate m.

m = 2 3π (2 -cosα) √ tanα (9)
The most reliable form of the hole inductance M h is available in [START_REF] Verpoorte | Advanced models for the transfer impedance of metal braids in cable harnesses[END_REF] but we do not detail this model here for the sake of brevity.

Tyni [START_REF] Tyni | The Transfer Impedance of Coaxial Cables with Braided Outer Conductor[END_REF] said that the magnetic fields respectively corresponding to crossing spindles interract. Hence, he added the braid inductance term (M b ) to the Vance's analytical formula to consider this phenomena. The braid inductance is defined equation 10.

M b = -μ d 4πD ĥ d (1 -tan 2 α) ( 10
)
Where ĥ [m] is the average height of the loops formed by the crossing conductors and is significant in determining the braid inductance. The average height is approximated by equation 11, where b [m] is the gap between two adjacent spindles and is defined by equation 12.

ĥ = 2d 1 + b/d (11) b = 2πD m C cos(α) -Nd ( 12
)
It is recommended in [START_REF] Verpoorte | Advanced models for the transfer impedance of metal braids in cable harnesses[END_REF] to compute the braid inductance term using the equation [START_REF] Tyni | The Transfer Impedance of Coaxial Cables with Braided Outer Conductor[END_REF] where the term S (equation 14) is a more accurate estimation of the surface between the crossing conductors.

M b = -μ S Nd 1 -tan 2 (α) 4πD m sin(2α) ( 13
)
S = Ndh + bd (1 -h 2 /d 2 ) 2 + Nd 2 (1 - π 4 ) (14)
Kley reviewed analytical solutions in [START_REF] Kley | Optimized single-braided cable shields[END_REF] and said that the height of the walls around the holes have to be considered for the magnetic field penetrating the hole produces Eddy current on the walls. This Eddy current creates a magnetic field which opposes to the one penetrating the hole. Hence, he introduced a semi-empirical corrective exponential term that reduces the value of the inductive term of Z t . He also added a corrective factor to the definition of the transfer inductance L t to consider the curvature of the braid. For the sake of brevity, we directly used the complete definition given by [START_REF] Verpoorte | Advanced models for the transfer impedance of metal braids in cable harnesses[END_REF] , which gave the most recent and most developed review on analytical models for transfer impedance determination.

II. NUMERICAL STUDIES OF BRAIDED SHIELDS

Numerical electromagnetic models has been less developed by authors because the necessary computing power is not available for long. The paper [START_REF] Otin | A finite element tool for the electromagnetic analysis of braided cable shields[END_REF] introduces a numerical electromagnetic model of the braided shield, in order to obtain the transfer impedance. The 3D model, as show in figure 4, respects the woven structure of the braid, which is hard to design. Though this model is very close to reality, the results of the transfer impedance processing was still a little different from the theory and measurement. The authors said that the discrepancies might come from the contact resistance between the strands, which is sensitive to small changes in the geometry. Using numerical electromagnetic model is considered as a good way to analyse and validate theorical approaches. Another paper from the same authors [START_REF] Otin | Finite element model for the computation of the transfer impedance of cable shields[END_REF] introduced a simplified numerical model based on perforated tube and brought the same conclusion.

As far as we know, [START_REF] Otin | A finite element tool for the electromagnetic analysis of braided cable shields[END_REF] gave the most reliable numerical model to compute the transfer impedance of a coaxial cable with braided shield. Hence, we use here the same sample of cable in order to obtain comparable results.

III. PEERING NUMERICAL MODELING WITH THEORY

A. Simplified numerical model of the coaxial cable

The model of coaxial cable shield we built was different of the one of [START_REF] Otin | A finite element tool for the electromagnetic analysis of braided cable shields[END_REF] (figure4). We didn't use woven elementary conductors for the shield, as shown in figure 5. The features of the model are given in table I. The sample of cable is instrumented according to the figure 6, which is a numerical implementation of the triaxial measurement setup presented in figure 1 and equation 1 is applied by using a post-processing. The results obtained for the simulation of the model of the figure 5 with the time domain solver of CST are shown in figure 7.

B. correction of numerical results

In [START_REF] Schippers | Electromagnetic analysis of metal braids[END_REF], the authors reviewed the origins of the inductance term of Z t . The M 12 term from equation 5, now called the hole inductance M h , can be completed by M b and M s , namely the braid inductance and the skin inductance. The braid inductance M b arises from the woven structure of the braid and corresponds to the lack of our nonwoven model of coaxial braided shield. The skin inductance M s is linked to the eddy current circulating in the wall of the apertures when the magnetic field penetrates the holes. M s has been introduced in the semi-empirical formula revelopped by Kley in [START_REF] Kley | Optimized single-braided cable shields[END_REF] and is not developed here for the sake of brevity. In order to correct the simulation result obtain with the simplified shield structure, we applied the equation 15 to the transfer impedance obtained with the numerical simulation.

Z t,corr = |Z t,sim + jωM b | (15)
Where M b is calculated using equations 13, 14 and 11.

IV. RESULT AND CONCLUSION The results corrected using Z t,corr are compared in figure 7 with raw simulation result and measured data extracted from [START_REF] Michel | Simple Method for Predicting a Cable Shielding Factor, Based on Transfer Impedance[END_REF]. The frequency range of the extracted measurement data is limited to [10 kHz; 1 GHz], while the limitation of the simulated frequency range can be chosen much wider.

A. Results and interpretation and correction

We see in the figure 7 that the raw result of the simulation is lower than the measured data extracted from [START_REF] Michel | Simple Method for Predicting a Cable Shielding Factor, Based on Transfer Impedance[END_REF]. This difference may merge from two sources. Firstly, the braid inductance term does not act in the simplified model. Secondly, the transfer impedance at low frequency, which is dominated by the DC resistance of the shield can change from one sample of RG58 to another. Though the RG58 model is standardized, cable manufacturers can use different material for the braid, for example pure copper or copper plated with tin or silver. The choice of the material can be a source of the discrepancy between the measurement and simulated data. The effect of the correction made by using the equation 15 obtain values of transfer impedance which are larger than the measured data from [START_REF] Michel | Simple Method for Predicting a Cable Shielding Factor, Based on Transfer Impedance[END_REF]. We considered that this was the effect of an overestimation of the transfer inductance M b . We used a curve fitting between the results from simulation and measurement. We found a transfer inductance 26 time smaller than the one given by equations 13, 14 and 11 and a DC resistance 7 mΩ.m -1 higher. The results obtained with this second correction are shown in figure 8.

We notice here that the curve corresponding the data obtained after applying the correction of the transfer inductance and add the DC resistance is much closer to the measured data.

B. Conclusions

In the paper, a novel approach to obtain the transfer impedance of coaxial cables with braided shield was considered. The transfer impedance was obtained using a combination of a simplified numerical electromagnetic model and analytic formulas. The model presented has an nonwoven structure as an approximation of the braided shield. The features of the model was corresponding to the standardized commercial coaxial cable RG58, the same as [START_REF] Michel | Simple Method for Predicting a Cable Shielding Factor, Based on Transfer Impedance[END_REF] considered, in order to obtain comparable results. The result of the simulation was corrected using an analytical formula from the review [START_REF] Verpoorte | Advanced models for the transfer impedance of metal braids in cable harnesses[END_REF]. The formula used for the correction added a term corresponding to the effect of the weaving of the braid. The corrected result was higher than the measurement. We deduced that the braid inductance was overestimated in literature. We used a curve fitting in order to number the correction factor to apply. We found that the braid inductance had to be divided by 26 and the DC resistance incremented of 7 mΩ.m -1 . The error on the braid inductance might come from the difficulty to calculate the average height of the carrier crossing. We thought error on the DC resistance might come from the choice of the material of the braid in our model, which can be different from the one of the cable used in the measurement taken as a comparison. Hence, we added 7 mΩ.m -1 to the simulation results. The obtained data fitted better to the measurement data. The paper introduced a concept of simulation that can still be improved in order to assess the shielding properties of a coaxial cable design. Further work may use a well defined sample of cable in order to remove the difference caused by the ignoring of the exact building parameters of the cable used for measurement and comparison. Furthermore, we proposed to revalue the analytical formula determining the so called braid inductance by dividing the previous equation by 26. This correction factor may be reevaluated with our own measurement data.

Fig. 1 .

 1 Fig. 1. Schematic representation of the triaxial setup for measurement of transfer impedance

Fig. 3 .

 3 Fig.3. Magnetic coupling through braid's hole[START_REF] Vance | Shielding Effectiveness of Braided-Wire Shields[END_REF]

Fig. 4 .Fig. 5 .

 45 Fig.4. 3D model of the braided coaxial cable shield from[START_REF] Otin | A finite element tool for the electromagnetic analysis of braided cable shields[END_REF]

Fig. 6 .

 6 Fig. 6. Numerical implementation of the triaxial measurement setup to determine the transfer impedance Zt

Fig. 7 .

 7 Fig. 7. Comparison between the measurement, raw results of simulation and corrected results of simulation of the magnitude of the transfer impedance Zt for a RG58 coaxial cable

Fig. 8 .

 8 Fig. 8. Comparison between the measurement, corrected simulation before and after curve fitting of the magnitude of the transfer impedance Zt for a RG58 coaxial cable

Proc. of the 2019 International Symposium on Electromagnetic Compatibility (EMC Europe 2019), Barcelona, Spain,September 2-6, 2019.


Chahinez Bouguerche

Delphine Gey

Jean-Lou Justine
email: justine@mnhn.frbouguerche

Fadila Tazerouti

Microcotyle Isyebi N M Sp

Erythrini Van Beneden

Hesse

M Erythrini

M Erythrinus

P. acarne, B. boops B. boops P Erythrinus

Towards the resolution of the Microcotyle erythrini species complex: description of Microcotyle isyebi n. sp. (Monogenea, Microcotylidae) from Boops boops (Teleostei, Sparidae) off the Algerian coast

Keywords: Cryptic species, New species, Monogenea, Mediterranean Sea, Integrative taxonomy Bouguerche et al

    Towards the resolution of the Microcotyle erythrini species complex: description of Microcotyle isyebi n. sp. (Monogenea, Microcotylidae) from Boops boops (Teleostei, Sparidae) off the Algerian coast Chahinez Bouguerche, Delphine Gey, Jean-Lou Justine, Fadila Tazerouti

Introduction

Microcotyle erythrini was described by Van Beneden & Hesse (1863) from the sparid Pagellus erythrinus collected off Brest (Brittany, Atlantic Ocean). The species has been since recorded from three other hosts (Pagellus acarne, Boops boops and Dentex dentex) in several localities in the Mediterranean (Table 1). This situation is somewhat puzzling since most monogeneans are considered to be highly host specific. Therefore, two hypotheses can be proposed: (a) M. erythrini is actually a monogenean with unusually wide specificity or (b) there are several species, each specific to a single host, which could not be distinguished by morphology. Molecular systematics is the tool of choice for resolving species complexes and recognising cryptic species [START_REF] Galimberti | Integrative taxonomy at work: DNA barcoding of taeniids harboured by wild and domestic cats[END_REF][START_REF] Glennon | Comparative phylogeography reveals host generalists, specialists and cryptic diversity: hexabothriid, microbothriid and monocotylid monogeneans from rhinobatid rays in southern Australia[END_REF][START_REF] Jousson | Cryptic speciation among intestinal parasites (Trematoda: Digenea) infecting sympatric host fishes (Sparidae)[END_REF][START_REF] Miller | Cryptic species of Euryakaina n. g. (Digenea: Cryptogonimidae) from sympatric lutjanids in the Indo-West Pacific[END_REF][START_REF] Vilas | A comparison between mitochondrial DNA and the ribosomal internal transcribed regions in prospecting for cryptic species of platyhelminth parasites[END_REF].

In this study, we used morphology and molecules to identify a species of Microcotyle found on B. boops off Algeria, a fish on which M. erythrini was previously recorded in various parts of the Mediterranean Sea and Atlantic Ocean. We found that morphology alone did not allow us to differentiate the species but that cytochrome c oxidase subunit I (COI) barcoding revealed wide differences with M. erythrini collected from its type-host. The species from B. boops is herein described as a new species. This paper is a part of an ongoing effort to characterise the parasite biodiversity of fish of the southern shores of the Mediterranean Sea [START_REF] Ayadi | A new species of Microcotyle (Monogenea: Microcotylidae) from Scorpaena notata (Teleostei: Scorpaenidae) in the Mediterranean Sea[END_REF][START_REF] Boudaya | Triloculotrema euzeti n. sp. (Monogenea, Monocotylidae) from the nasal tissues of the blackspotted smooth-hound Mustelus punctulatus (Carcharhiniformes, Triakidae) from off Tunisia[END_REF][START_REF] Bouguerche | Microcotyle visa n. sp. (Monogenea: Microcotylidae), a gill parasite of Pagrus caeruleostictus (Valenciennes) (Teleostei: Sparidae) off the Algerian coast, Western Mediterranean[END_REF][START_REF] Chaabane | Pseudorhabdosynochus regius n. sp. (Monogenea, Diplectanidae) from the mottled grouper Mycteroperca rubra (Teleostei) in the Mediterranean Sea and Eastern Atlantic[END_REF]Chaabane et al. , 2016aChaabane et al. , b, 2017;;[START_REF] Chaari | Axinoides euzeti n. sp. (Monogenea: Axinidae) from the gills of the needlefish Tylosurus acus imperialis (Rafinesque) (Belonidae) off Tunisia, with an updated list of hosts and localities for Axinoides spp[END_REF][START_REF] Kheddam | Hexabothriid monogeneans from the gills of deep-sea sharks off Algeria, with the description of Squalonchocotyle euzeti n. sp. (Hexabothriidae) from the kitefin shark Dalatias licha (Euselachii, Dalatiidae)[END_REF][START_REF] El Ouahed-Amine | Contribution à l'étude des Monogènes parasites des poissons Sparidae (Téléostéens) du littoral Algérois. Approche taxonomique et écologique[END_REF].

Material and methods

Fish

From 2015 through 2017, 2004 specimens of B. boops were obtained dead from fishermen in Bouharoun, Algerian coast (36° 37′ N, 2° 39′ E). Fish specimens were transferred to the laboratory shortly after capture and identified using keys [START_REF] Fischer | Fiches FAO d'identification des espèces pour les besoins de la pêche[END_REF]. Gills were removed from each fish and were observed under a microscope for the presence of monogeneans.

Monogeneans

Morphological methods

Monogeneans were removed alive from gills using fine dissection needles, then fixed in 70%

Molecular methods

To ensure that hosts and monogenean were labelled with respect of host-parasites relationships, we followed a precise protocol [START_REF] Ayadi | A new species of Microcotyle (Monogenea: Microcotylidae) from Scorpaena notata (Teleostei: Scorpaenidae) in the Mediterranean Sea[END_REF][START_REF] Bouguerche | Microcotyle visa n. sp. (Monogenea: Microcotylidae), a gill parasite of Pagrus caeruleostictus (Valenciennes) (Teleostei: Sparidae) off the Algerian coast, Western Mediterranean[END_REF][START_REF] Rahmouni | The monogenean which lost its clamps[END_REF]. One specimen of Microcotyle sp. was extracted, and a tissue sample from the gill of the fish harbouring it was taken. The monogenean was cut in three parts using a scalpel blade. The anterior part (which includes the genital atrium) and the posterior part (which contains the testes and the haptor) were mounted, on a single slide, for deposition in a museum; the middle part was preserved in absolute ethanol then subjected to molecular analyses. This protocol ensures that the sequenced monogenean specimen actually corresponds to the species described and that the sequenced host is precisely identified.

Molecular barcoding of fish

Total genomic DNA was isolated with a QIAamp DNA Mini Kit (Qiagen) as per the manufacturer's instructions. The 5′ region of the mitochondrial COI gene was amplified with the primers Fish F1 (5 ′-TCAAC CAACCACAAAGACATTGG CAC-3 ′) and Fish R 1 ( 5 ′ -TAGA CTTCTGG GTG GCCAAAG AATCA -3 ′) [START_REF] Ward | DNA barcoding Australia's fish species[END_REF] to edit the sequence, which was 637 bp in length, compared it to the GenBank database content with BLAST and deposited it in GenBank under accession number MK317921. Species identification was confirmed with the BOLD identification engine [START_REF] Ratnasingham | BOLD: the barcode of life data system (www.barcodinglife.org)[END_REF].

Bouguerche et al.

Microcotyle isyebi 5

COI sequences of monogeneans

Total genomic DNA was isolated using the QIAamp DNA M i c r o Ki t ( Q i a g e n ) . The specific primers J B 3 (=COIASmit1) (forward 5′-TTTTTTGGGCATCCTGAGGT TTAT-3′) and JB4.5 (=COI-ASmit2) (reverse 5′-TAAA GAAAGAACATAATGAAAATG-3′) were used to amplify a fragment of 396 bp of the COI gene [START_REF] Bowles | A molecular phylogeny of the human schistosomes[END_REF][START_REF] Littlewood | Parasite speciation within or between host species?-phylogenetic evidence from site-specific polystome monogeneans[END_REF]. PCR reaction was performed in 20 μl, containing 1 ng of DNA, 1× CoralLoad PCR buffer, 3 mM MgCl2, 0.25 mM dNTP, 0.15 μM of each primer and 0.5 units of Taq DNA polymerase (Qiagen).

Thermocycles consisted of an initial denaturation step at 94 °C for 2 min, followed by 37 cycles of to the Microcotylidae. The trees were inferred using the neighbour-joining method [START_REF] Saitou | The neighbor-joining method: a new method for reconstructing phylogenetic trees[END_REF] and the maximum likelihood method using MEGA7 [START_REF] Kumar | MEGA7: Molecular Evolutionary Genetics Analysis version 7.0 for bigger datasets[END_REF]. For the latter, the best model, estimated by MEGA7, was the Hasegawa-Kishino -Yano model [START_REF] Hasegawa | Phylogenetic relationships among eucaryotic kingdoms inferred from ribosomal RNA sequences[END_REF] with discrete Gamma distribution (HKY+G). Bootstrap numbers were 10,000 for NJ and 100 for ML. Genetic distances (p-distance and Kimura-2 parameter [START_REF] Kimura | A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences[END_REF]) distance) were estimated with MEGA7.

All codon positions were used.

Results

Molecular identification of fish

The provisional identification of fish species using morphological characteristics was confirmed by DNA barcoding approach. BLAST analysis of the COI sequence of the fish specimen of the present study with NCBI and BOLD database showed sequence similarity values of 100% for B. boops, thus confirming the identification. The BOLD database [START_REF] Ratnasingham | BOLD: the barcode of life data system (www.barcodinglife.org)[END_REF] includes many sequences of Bouguerche et al.

Microcotyle isyebi 6

B. boops with published information, and thus, we are confident that the identification is valid.

Molecular characterisation of monogeneans

The COI sequence of M. isyebi n. sp. was aligned with other microcotylid sequences. For trees, the neighbour-joining and maximum likelihood methods led to slightly different topologies; we show only the former in Fig. 1. The analysis involved 14 nucleotide sequences, and there were a total of 294 positions in the final dataset. M. isyebi n. sp. differed from a sequence of M. erythrini from the type-host P.

erythrinus [START_REF] Jovelin | Phylogenetic relationships within the polyopisthocotylean monogeneans (Platyhelminthes) inferred from partial 28S rDNA sequences[END_REF] and two distinct sequences of Microcotyle visa from Pagrus caeruleostictus by 16.3%, 9.5% and 10.7%, respectively (Table 3). and localities are distant (Mediterranean Sea vs New York). M. isyebi can be differentiated from all other species mentioned above, except species from sparid hosts, by the presence of two lateral expansions in the genital atrium.

M. isyebi differs from

Bouguerche et al.

Microcotyle isyebi

Microcotyle isyebi 25

Figure 2

  Microcotyle lichiae by clamp number (83 vs 52), oral organ length (59 vs 220) and the arrangement of spines in the atrium (five concentric rows in M. lichiae). The host is also different (Lichia amia, Carangidae). M. isyebi resembles Microcotyle donavini by clamp number (54-102 vs 86), length (25-62 vs 33-50) and genital atrium length (65-170 vs 250). However, it differs from it by the general arrangement of ovary, host (B. boops vs Labrus bergylta) and locality (Mediterranean Sea vs Atlantic). M. isyebi differs from Microcotyle pomatomi by clamp number (54-102 vs 104-148), genital atrium length (65-170 vs 109-134), arrangement of genital atrium (absence of pockets in M. pomatomi) and testis number ( 13 -25 vs 26 -40). Hosts ( B. boops vs Pomatomus saltatrix) and localities (Mediterranean Sea vs Pacific) are different.

Figure 1 .Figure 2 .Figure3. 1

 121 Figure 1. Tree inferred using the neighbour-joining method; only bootstrap values higher than 70 are indicated. The new species, Microcotyle isyebi n. sp. and Microcotyle erythrini (from its type-host), are in different colours (blue and red), the two species are clearly different and are not sister groups

  Bouguerche et al. ethanol, stained with acetic carmine, dehydrated in ethanol series (70%, 96% and 100%), cleared in clove oil and finally mounted in Canada balsam. Drawings were made with the help of an Olympus BH-2 microscope with Differential Interference Contrast and a drawing tube. Drawings were scanned and redrawn on a co mp uter with Adob e Illustrator . Measurements are in micrometres and indicated as means ± standard deviation if n > 30 and between parentheses the range and number of measurements. Measurements of holotype are indicated

	Microcotyle isyebi	4

  All available sequences of Microcotyle spp. available in GenBank and one sequence of Microcotyle isyebi n. sp. generated in this study were included in the phylogenetic analyses (Table2). A sequence deposited in GenBank as 'Paramicrocotyle sp.' was included since this genus is now considered a

	denaturation at 94 °C for 30 s, annealing at 48 °C for 40 s and extension at 72 °C for 50 s. The final
	extension was conducted at 72 °C for 5 min. The sequence was edited with CodonCode Aligner software
	version 3.7.1, compared to the GenBank database content with BLAST and deposited in GenBank under
	accession number MK317922.
	Trees and distances

junior synonym of Microcotyle

[START_REF] Bouguerche | Microcotyle visa n. sp. (Monogenea: Microcotylidae), a gill parasite of Pagrus caeruleostictus (Valenciennes) (Teleostei: Sparidae) off the Algerian coast, Western Mediterranean[END_REF]

. Sequences of Bivagina pagrosomi

(Murray, 1931)

and Polylabris halichoeres Wang & Zhang, 1998 were use d as outgroup. All these species belong

  The high divergence strongly suggests that the new species is distinct from M. erythrini as well as from all the other species of Microcotyle from sparid hosts with available COI sequences. The sequence of M. isyebi n. sp. was different from sequences of Microcotyle algeriensis and Microcotyle sp. from Scorpaenidae off the Algerian coast by 14.7% and 13%, respectively. Histoire Naturelle(MNHN 306HG, Box 12, slides 3,(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) 25). Vas deferens relatively wide, visible from middle of body, conspicuous in midline dorsal to uterus and opening into genital atrium.Vaginal pore well visible in some specimens, mediodorsal, posterior to genital atrium; distance from vagina to anterior extremity 551 (410-700, n = 11). Vaginal duct not seen. Ovary complex begins at level of anteriormost testes. Proximal section irregularly shaped, often overlapping anteriormost testis; ovary continues anteriorly in midline, reflexes at level of confluence of vitelline ducts, reflexes again toward anterior extremity, forms large anterior curve and reflexes a last time posteriorly and ends as oviduct. specimens) runs from oviduct ventrally across proximal end of ovary and enters right intestinal caecum.Ootype spindle-shaped, with posterior Mehlis' glands. Uterus in midline. Seminal receptacle well visible, lateral. Vitellarium co-extensive with intestinal caeca reaching up to haptor region. Vitelline ducts paired, united anteriorly and posteriorly; anterior junction in inverted Y well visible in some specimens; Table5). They share also the same type-locality (Algeria, Mediterranean Sea). However, hosts are different ( B. boops vs P. caeruleostictus) and the COI divergence is high, 9.5-10.7%.M. isyebi resembles Microcotyle omanae in clamp number (54-102 vs 94-120), length of genital atrium (65-170 vs 25-214) and testis number (13-25 vs 10-17). However, they differ in testis number(13-25 vs 35-55). The hosts are different (B. boops vs Cheimerius nufar) and from distant localities (Mediterranean Sea vs Indian Ocean). . isyebi has the same locality as Microcotyle sp. ofAyadi et al., 2017 from Helicolenus

	Bouguerche et al.	Microcotyle isyebi	8
	Description
	Based on 31 specimens; measurements of holotype indicated as h. Body elongate, anterior end narrow,
	length of body proper h 3810, 2647 ± 514 (1750-3810, n = 32), length of haptor h 870, 809 ± 164 posterior junction Y-shaped, conspicuous in most specimens, at level of ovary and ventral to it. Egg
	(500-1250, n = 32), total length including haptor h 4680, 3480 ± 600 (2370-4750, n = 31); maximum fusiform, with two filaments; length of egg 223 (125-260, n = 23), width 70 (45-95, n = 23). Egg
	Paratype of specimen with molecular analysis: Slide MNHN HEL919, COI barcode GenBank MK317922; this specimen has 237 spines in main group of atrium, 35 in pockets, total number 272; 23 testes; 95 clamps. COI barcode of individual host fish harbouring this paratype, GenBank MK317921. width at level of ovary h 750, 598 ± 159 (310-830, n =32). Haptor triangular, subsymmetrical or symmetrical, h 870, 809 ± 164 (500-1250, n = 32) long. Haptor armed with h 92, 83 (54-102, n = 25) clamps. Clamps of microcotylid type, arranged in two equal or sub-equal rows. Clamps dissimilar in size: posterior and newly formed anterior clamps smallest. Length of largest clamps 42 ± 11 (25-62, n = 41), width 17 ± 4 (10-31, n = 40) (Figs. 2 and 3). Two oval prohaptoral suckers 59 ± 8 (40-75, n = 34) length × 44 ± 9 (30-65, n = 34) width; row of tiny papillae visible on ventral rims. Pharynx small, subspherical 40 ± 7 (25-50, n = 34) length × 38 ± 5 (30-48, Oviduct joined by vitelline reservoir in midline. Genito-intestinal canal (visible only in certain filaments, often coiled, more than 223 (125-260, n = 23) in length. Discussion Molecular differentiation Although this limit is not absolute, it is generally considered that a difference of 4% in COI sequences suggests that species are different (Aquaro et al. 2012; Ward 2009; Ward et al. 2005); intraspecific differences of COI sequences ranging 0.2-5.6% have been reported in various polyopisthocotylean clamp number (54-102 vs 86-110), number of spines in the main group of atrium (136-230 vs 201-255) and in pockets (18-38 vs 31-34), clamp length (25-62 vs 50-75) and testis number (13-29 vs 16-17). The specimens of M. erythrini from the collection of Louis Euzet that we examined could only be distinguished by their COI distance (16.3%); they have different type-hosts (B. boops vs Pagellus erythrini). M. isyebi is similar to M. visa from P. caeruleostictus in clamp number (54-102 vs 59-126), number of spines in pockets (18-38 vs 18-39), number of testes (13-25 vs 14-29), size of clamps, oral organ clamp number (54-102 vs 20-39), number of spines in genital atrium (265-267 vs 76-174) especially in pockets (18-38 vs 7) and testis number (13-25 vs 9-20). They differ also by host (B. and pharynx (M. isyebi has the same type-locality as M. algeriensis (Algeria, Mediterranean Sea). They differ in boops vs Scorpaena notata) and the COI divergence is high (14.7%).

Microcotyle isyebi n. sp.

Type-host: B. boops (Linnaeus, 1758) (Sparidae).

Type-locality: Off Bouharoun, Algerian coast (36° 37′ 24.17″ N, 2° 39′ 17.38″ E).

Site on host: Gills. Prevalence and intensity: 15% (298/2004), up to 3 monogeneans/fish. Type-specimens: Holotype (MNHN HEL918) and 31 paratypes on 28 slides (MNHN HEL919-946) deposited in the collections of the Muséum National d'Histoire Naturelle, Paris. Etymology: The species is named after ISYEB, an acronym for 'Institut de Systématique, Évolution, Biodiversité' as an acknowledgement of the help offered to the first author. Material examined for comparison: 15 specimens of M. erythrini from type-host P. erythrinus from Sète, French Mediterranean Coast, from the collection of Louis Euzet deposited in the Muséum National d'n = 34) width, be-hind oral organs. Intestine caeca beginning at level of genital atrium, with numerous lateral and medial diverticula. Caeca probably not confluent. Right caecum terminates near beginning of haptor, left branch extends into haptor for a short distance. Testes post-ovarian, intercaecal, limited to posterior half of body proper, subspherical to oval, h 21, 20 ± 5 (13-29, n = 30) in number. Vas deferens, runs along body midline to genital atrium. Genital atrium at h 335, 259 ± 45 (175-375, n = 31) from anterior end of body, length h 110, 96 ± 21 (65-170, n = 31), width h 90, 90 ± 18 (45-120, n = 31). Genital atrium comprises anterior atrium proper and two posterior 'p o c k e t s ' . Atrium proper roughly shaped as inverted heart, bearing numerous conical spines, of similar sizes, spines apparently more dense in centre than in bilateral parts. Lumen with two lateral expansions visible only after variation in focus. Posterior pockets lined with spines similar to that of atrium proper. Number of spines in atrium proper 186 (136-230, n = 4), in pockets 31 (18-38, n = 4), total 216 (154-267, n = 4). Genital pore middorsal.

monogeneans

[START_REF] Aquaro | Sciadicleithrum variabilum (Dactylogyridae: Monogenea) infection in Symphysodon discus: a case report[END_REF][START_REF] Ayadi | A new species of Microcotyle (Monogenea: Microcotylidae) from Scorpaena notata (Teleostei: Scorpaenidae) in the Mediterranean Sea[END_REF][START_REF] Bouguerche | Microcotyle visa n. sp. (Monogenea: Microcotylidae), a gill parasite of Pagrus caeruleostictus (Valenciennes) (Teleostei: Sparidae) off the Algerian coast, Western Mediterranean[END_REF][START_REF] Preez | Polystoma floridana n. sp. (Monogenea: Polystomatidae), a parasite in the green tree frog, Hyla cinerea (Schneider), of North America[END_REF][START_REF] Héritier | Introduction and invasion of the red-eared slider and its parasites in freshwater ecosystems of southern Europe: risk assessment for the European pond turtle in wild environments[END_REF][START_REF] Li | Phylogeographical pattern of Mazocraeoides gonialosae (Monogenea, Mazocraeidae) on the dotted gizzard shad, Konosirus punctatus, along the coast of China[END_REF][START_REF] Mladineo | Molecular evidence for the lack of transmission of the monogenean Sparicotyle chrysophrii (Monogenea, Polyopisthocotylea) and isopod Ceratothoa oestroides (Crustacea, Cymothoidae) between wild bogue (Boops boops) and cage-reared sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax)[END_REF][START_REF] Oliva | Parapedocotyle prolatili gen. n. et sp. n., a representative of a new subfamily of the Diclidophoridae (Monogenea), a gill parasite of Prolatilus jugularis (Teleostei: Pinguipedidae) from Chile[END_REF][START_REF] Sepúlveda | Patterns of genetic variation and life history traits of Zeuxapta seriolae infesting Seriola lalandi across the coastal and oceanic areas in the southeastern Pacific Ocean: potential implications for aquaculture[END_REF][START_REF] Shi | Phylogeography and demographic history of Gotocotyla sawara (Monogenea: Gotocotylidae) on Japanese Spanish mackerel (Scomberomorus niphonius) along the coast of China[END_REF][START_REF] Tambireddy | Molecular characterization and phylogeny of some mazocraeidean monogeneans from carangid fish[END_REF][START_REF] Yan | Comparative phylogeography of two monogenean species (Mazocraeidae) on the host of chub mackerel, Scomber japonicus, along the coast of China[END_REF][START_REF] Yoshinaga | Origin of the diclidophorid monogenean Neoheterobothrium hirame Ogawa, 1999, the causative agent of anemia in olive flounder Paralichthys olivaceus[END_REF]

. With a difference of 16.3% between the species from B. boops and the of sequence M. erythrini from the type-host, our molecular analysis strongly suggests that the species described here, M. isyebi n. sp., is different from M. erythrini. Similar high interspecific differences have also been reported for other platyhelminths such as triclads

[START_REF] Winsor | Giant worms chez moi! Hammerhead flatworms(Platyhelminthes, Geoplanidae, Bipalium spp., Diversibipalium spp.) in metropolitan France and overseas French territories[END_REF]

. The new species also shows a clear COI divergence from all other species of Microcotyle from sparid hosts, but the database does not include all species.

Differential diagnosis for M. isyebi n. sp. M. isyebi is not distinguishable from M. erythrini in various measurements and counts (Table 4): Mdactylopterus (Algeria, Mediterranean Sea). These species also resemble in testis number (13-25 vs 10-17); however, they differ in clamp number (54-102 vs 49-58) and total number of spines in genital atrium (265-267 vs 122-333) and in pockets (18-38 vs 12). Hosts are different (B. boops vs H. dactylopterus) and COI divergence is high (13%). M. isyebi resembles Microcotyle archosargi in clamp number (54-102 vs 106) and length (42-62 vs 80). It can be distinguished from it by the shape and armature of the genital atrium since lateral expansions and pockets are absent in M. archosargi. Hosts are different (B. boops vs Archosargus probatocephalus)

11 Table 1 .

 111 Previous record of Microcotyle erythrini

	Bouguerche et al.	Microcotyle isyebi	12
	Host and locality	Source
	Pagellus erythrinus (type-host)	Van Beneden and Hesse (1863)
	France, Atlantic
	Montenegro, Mediterranean Sea	Radujkovic and Euzet (1989)
	France, Mediterranean Sea	Euzet (1957), Jovelin and Justine (2001)
	Italy, Mediterranean Sea	Parona and Perugia (1890), Ulmer and James (1981)
	Algeria, Mediterranean Sea	Kaouachi et al. (2010), Kouider El Ouahed-Amine (1998)
	Boops boops
	France, Mediterranean Sea	Renaud et al. (1980)
	Italy, Mediterranean Sea	Parona and Perugia (1890), Strona et al. (2010)
	Spain, Atlantic Ocean	Pérez-del Olmo et al. (2007b)
	Spain, Mediterranean Sea	Fernandez-Jover et al. (2010), López-Román and Guevara Pozo
		(1973), Marzoug et al. (2012)
	Spain, Atlantic Ocean and	Pérez-del Olmo et al. (2007a, 2008),
	Mediterranean Sea	Power et al. (2005)
	Turkey, Mediterranean Sea	Akmirza (2013)
	Algeria, Mediterranean Sea	Benhamou et al. (2017), Marzoug et al. (2012), Ramdane et al. (2013)
	Pagellus acarne
	Turkey, Mediterranean Sea	Akmirza (2013)
	Italy, Mediterranean Sea	Parona and Perugia (1890)
	Dentex dentex
	Spain, Mediterranean Sea	González et al. (2004)

Table 2 .

 2 Species of the Microcotylidae used in the present molecular study. a New sequence. b The taxonomic identity of this species has been questioned[START_REF] Ayadi | A new species of Microcotyle (Monogenea: Microcotylidae) from Scorpaena notata (Teleostei: Scorpaenidae) in the Mediterranean Sea[END_REF]. c Paramicrocotyle sp. included with species of Microcotyle in this study[START_REF] Bouguerche | Microcotyle visa n. sp. (Monogenea: Microcotylidae), a gill parasite of Pagrus caeruleostictus (Valenciennes) (Teleostei: Sparidae) off the Algerian coast, Western Mediterranean[END_REF]

	Parasite species	Host species	Origin	GenBank	Source
	Microcotyle isyebi n. sp.	Boops boops	Algeria	MK317922 a	Present study
	Microcotyle visa	Pagrus	Algeria	MK27652	Bouguerche et al.
		caeruleostictus			(2019)
	Microcotyle visa	Pagrus	Algeria	MK27653	Bouguerche et al.
		caeruleostictus			(2019)
	Microcotyle visa	Pagrus	Algeria	MK27654	Bouguerche et al.
		caeruleostictus			(2019)
	'Microcotyle sebastis' b	Sebastes schlegeli	South Korea	NC009055	Park et al. (2007)
	Microcotyle erythrini	Pagellus erythrinus	France	AY009159	Jovelin and Justine
	Paramicrocotyle sp. c	Pinguipes chilensis	Chile	KJ794215	(2001) Oliva et al.
					(2014)
	Microcotyle sp.	Helicolenus	Algeria	KX926446	Ayadi et al. (2017)
		dactylopterus
	Microcotyle sp.	Helicolenus	Algeria	KX926447	Ayadi et al. (2017)
		dactylopterus
	Microcotyle algeriensis	Scorpaena notata	Algeria	KX926443	Ayadi et al. (2017)
	Microcotyle algeriensis	Scorpaena notata	Algeria	KX926444	Ayadi et al. (2017)
	Microcotyle algeriensis	Scorpaena notata	Algeria	KX926445	Ayadi et al. (2017)
	Bivagina pagrosomi	Sparus aurata	Australia	Z83003	Littlewood et al.
					(1997)
	Polylabris halichoeres	Halichoeres	China	JF505509	Zhang et al. (2011)
		nigrescens

Table 3 .

 3 Distances between taxa. Distances shown here are percentages, according to Kimura two-parameter; p distances (not shown) were similar but generally slightly lower.

	1	2	3	4	5	6	7	8	9	10 11	12 13

Table 5 .

 5 Measurements of Microcotyle isyebi n. sp. from Boops boops off Algeria, compared with Microcotyle spp. recorded from the Mediterranean and from sparid hosts. Note that M. donavini and M. pomatomi were recorded from the Mediterranean Sea, but measurements are only available for specimens from elsewhere (English Channel and Pacific, respectively). a Provided as diameter.

		Microcotyle isyebi	Microcotyle visa	Microcotyle	M. algeriensis	M. lichiae	M. donavini	M. pomatomi	M. omanae	M. archosargi
		n. sp.	Bouguerche	sp. of Ayadi	Ayadi et al.,	Ariola, 1899	Van Beneden	Goto, 1899	Machkewskyi	MacCallum, 1913
			et al., 2019	et al., 2017	2017		& Hesse, 1863		et al., 2013
	Hosts	Boops boops	Pagrus	Helicolenus	Scorpaena	Lichia amia	Symphodus	Pomatomus	Cheimerius nufar Archosargus
			caeruleostictus	dactylopterus	notata		mediterraneus	saltatrix		probatocephalus
	Locality	Bouharoun, Cap	Zemmouri, Algeria,	Bouharoun, Algeria,	Bouharoun, Algeria,	Genova, Italy,	Roscoff, English	Perth, Western	Shuweymiyyah	New York fish
		Djinet, Algeria,	Mediterranean	Mediterranean Sea	Mediterranean Sea	Mediterranean	Channel	Australia,	and Sharbithat,	market
		Mediterranean	Sea			Sea		Pacific	Arabian Sea,
		Sea							Indian Ocean
	Source	Present study	Bouguerche	Ayadi et al.	Ayadi et al.	Ariola (1899)	Euzet and Marc	Williams	Machkewskyi et	MacCallum (1913)
			et al. (2019)	(2017)	(2017)		(1963)	(1991)	al. (2013)
	Body length	2647 ± 514 (1750-3810,	1998 (1300-
		n = 32)	4000)
	Haptor length	809 ± 164 (500-1250, n = 32)	739 (250-1250)	962 (570-1200)	781 (450-1040)			976 (464-1680) 1125-3225	1500
	Total length	3480 ± 600 (2370-4750,	2737	3092 (410-	3298 (1900-	8000	4000-5000	3416	6020	8000
		n = 31)	(1910-4620)	3800)	4300)			(3040-4080)	(3500-11,000)
	Body width	598 ± 159 (310-830,	500 (270-1000)			500	400-500	408 (400-416)		800
		n = 32)

Microcotyle isyebi

Acknowledgements

The authors are indebted to Amina Boutellis, Zouhour El Mouna Ayadi and Samia Terkmani for their continued support. Our thanks are also due to the fishermen from Bouharoun especially Mohamed Kayrouz. This work was funded by FSB, USTH, Algeria, and ISYEB, MNHN, France. The authors thank the three anonymous reviewers for their constructive suggestions and comments.

Microcotyle isyebi 10

M. erythrini as a cryptic species

After the early record of [START_REF] Parona | Contribuzione per una monografia del genere Microcotyle[END_REF], there are several records of M. erythrini in B.

boops in the literature (Table 1). These authors, in the absence of molecular information, were correct in ascribing the species found to M. erythrini and we would have done the same in a similar situation.

We could not distinguish our new species from specimens of M. erythrini from the type-host from Louis Euzet's collection; body length was greater in M. isyebi, but such measurements of 'soft' body parts are generally not good characteristics for the differentiation of microcotylids [START_REF] Williams | Monogeneans of the families Microcotylidae Taschenberg, 1879 and Heteraxinidae Price, 1962 from Western Australia, including the description of Polylabris sandersae n. sp. (Microcotylidae)[END_REF]). However, our paper demonstrates that the species of Microcotyle found on B. boops in Algeria, here described as M. isyebi, is a distinct species, based on an analysis of molecular data but still with major morphological resemblances. We note that M. isyebi n. sp. closely resembles M. erythrini in body shape, general armament of genital atrium and in clamp number (54-102 vs 86-110) which are generally considered the best characteristics to distinguish Microcotyle species [START_REF] Ayadi | A new species of Microcotyle (Monogenea: Microcotylidae) from Scorpaena notata (Teleostei: Scorpaenidae) in the Mediterranean Sea[END_REF]. We conclude that it is likely that previous reports of M. erythrini in B. boops were, in fact, findings of M. isyebi.

It remains that M. erythrini, in addition to its type-host P. erythrinus, has also been recorded from two other host fish, P. acarne and D. dentex (Table 1). It would be interesting to obtain COI sequences of the Microcotyle specimens from these host fish and possibly detect the presence of additional new species.

Microcotyle isyebi 15

Testis number 20 ± 5 ( 13 Note that M. donavini and M. pomatomi were recorded from the Mediterranean Sea, but measurements are only available for specimens from elsewhere (English Channel and Pacific, respectively) a Provided as diameter

Microcotyle isyebi 26