COMMINICATION-First Record of the Pempheris rhomboidea ( Kossmann & Räuber , 1877 ) from Mersin Bay , Northeastern Mediterranean Sea

In this study, eight individuals of Pempheris rhomboidea (Kossmann & Räuber, 1877) were for the first time caught in the Mersin Bay, Northeastern Mediterranean Sea. Some morphometric and meristic characters of these individuals were measured. The average standard length (SL): 90.13 mm, total length (TL): 112.62 mm, the length of longest pectoral fin (LPF): 25.88 mm, the length of longest dorsal fin ray (LDF): 21.25 mm, SL/LPF: 3.88, SL/LDF: 4.24, A: III, 39-42; D: VI, 9; LL pore scales: 55-58. The ratio of eye diameter (ED) to standard length (SL) is 7.95. The presence of the non-indigenous Pempheris rhomboidea was reported for the first time from Northeastern Mediterranean Sea and second time fromTurkish marine waters.


Introduction
P. rhomboidea (Kossmann & Räuber, 1877) belongs to the Pempheridae family of Perciformes (Romero, 2002).The average standard length of this species is 13.2 cm (Randall & Victor, 2015).P. rhomboidea is a neritic species, which lives in the pelagic region, the coral reef and the rocky outcrop of the tropical and temperate waters in the Indo-Pacific and Western Atlantic (Azzurro et al., 2015).Their body is shaped rhomboid flattened from the sides, and this species is characterized by big eyes and short nose.They usually go out at night to feed on zooplankton in the reefs in which they live in bulk (Mooi & Randall 2014;Randall & Victor, 2015).It is reported that the species is an invasive species that migrated from the Red Sea to the Mediterranean Sea and changed the structure of the ecosystem (Azzurro et al., 2015).
The identification of species belonging to Pempheris genus are very difficult.With the help of systematic and molecular studies, errors in the nomenclature of the species belonging to this genus have been tried to be corrected (Koeda et al., 2014;Azzurro et al., 2015).Goren (1986) stated that even in a particular geographic region, there could be taxonomic problems related to these species and the number of species could change.Dor (1984) reported that P. mangula, P. oualensis, P. schwenkii, and P. vanicolensis belonging to Pempheris genus in Red Sea whereas Golani & Diamant (1991) have only accepted the presence of P. vanicolensis in the Red Sea.Goren & Dor (1994) added P. molucca to the species list and also reported the distribution of five Pempheris species in the Red Sea.Golani & Bogorodsky (2010) reported two species of Pempheris, P. schwenkii, P. rhomboidea, in the fish check-list of Red Sea.Randall et al. (2013) argued that P. vanicolensis should be named as P. flavicycla marisrubri (Azzurro et al., 2015).
According to Eschmeyer (2013), there are 48 species belonging to the Pempheridae family, however 30 species of them are valid species.This family consists of 4 species containing Parapriacanthus genus and 26 species containing Pempheris genus (Koeda et al. 2013;Randall & Victor, 2015).Koeda et al. (2014) reported that there are 4 different species of Pempheris genus (P.adusta, P. mangula, P. nesogallica, and new species P. tominagai).Randall et al. (2014) refuted the information belonging to the 4 Pempheris species which were claimed to be distributed in the Red Sea by Koeda et al. (2014).Randall & Bineesh (2014) reported 5 species of Pempheris genus in the Indian Ocean.These include: P. flavicycla; P. malabarica; P. mangula identified as a neotype; P. sarayu was reported as a new species, and P. schwenkii which is the first record for India.Azzurro et al. (2015) reported the presence of P. flavicycla, P. rhomboidea, and P. tominagai in the Red Sea as a result of molecular analysis.Randall & Victor (2015) stated that 34 species identified in the Indian Ocean belonging to the genus Pempheris have reached 47 species.Iglésias & Frotté (2015) reported P. rhomboidea from Coast of Cyprus in the fish checklist.Akyol et al. (2017) reported the first record of P. rhomboidea from the Aegean Sea.The first species record of the Pempheris from Mersin Bay has been reported as P. vanicolensis (Gücü et al., 1994).In a later study, P. vanicolensis was recorded in the Gulf of Antalya (Bilecenoğlu & Taşkavak, 1999).It was previously reported that P. mangula was identified as P. vanicolensis in the Mediterranean Sea (Froese & Pauly, 2018).
In this research, it is aimed to determine the species of 8 individuals of Pempheris genus catching from Mersin Bay and to determine some morphometric and meristic measurements of individuals.In addition, it was aimed to gather together the issues related to the identification of species in this genus.

Materials and Methods
Eight individuals of P. rhomboidea (Kossmann & Räuber, 1877) were caught by a trammel net at a depth of 30 m on 10 May 2018 in the Northeastern Mediterranean Sea (Mersin Bay) (coordinate: 36°46′20″N, 34°36′57″E).These specimens were preserved in 4% formalin and were deposited in the Museum of the Systematic, Faculty of Fisheries, Mersin University, (catalogue number: MEUFC-18-11-077).This species belongs to Pempheridae Family of Perciformes.Morphometric    The key features used in the identification of species belonging to the genus Pempheris are shown below.

Results
In this study, eight individuals of P. rhomboidea (Kossmann & Räuber, 1877) were caught by a trammel net at a depth of 30 m out in Mersin Bay.The average of some morphometric measurements of eight individuals and their standard errors are shown in the Table 1.While body color of all individuals has silvery, fins are yellowish and the ends of the fins are black line.The meristic characters of these species caught in Mersin Bay were found A: III, 39-42; D: VI, 9-10, LL: 55-58.

Discussion
P. rhomboidea is a non-indigenous species that migrate from Red Sea to the Mediterranean Sea since the opening of the Suez Canal.The first records of the species were given in the 1800s (Russell 1803;Cuvier, 1829).The identification of species belonging to this family of Indo-Pasific are generally based on the distribution areas and morphometric properties (Koeda et al., 2014;Randall & Bineesh 2014).There have been various misidentification in identifying the species and different opinions have been put forward (Koeda et al., 2014;Randall et al., 2014;Akyol et al., 2017).These misidentifications have been tried to be corrected by the molecular studies (Azzurro et al., 2015).
The keys belonging to Pempheridae family were formed (Azzurro et al., 2015;Randall & Victor, 2015).These keys were used in the identification of these individuals caught from Mersin Bay.The number of pore scales on the line lateral was 55-58 and the number of anal fin soft rays were 39-42, spines were 3.The SL/LDF ratio was determined as 4.24 in this study.According to the number of lateral-line pored scales (54-57) and anal rays (32-39) (Azzurro et al., 2015) and according to the SL/LDF ratio (4.05-4.25)(Randall & Victor, 2015) the species was determined to be P. rhomboidea.We have determined that the measurements obtained from individuals for identification are compatible with both keys.Koeda et al., (2014) reported that Pempheris species entering the Levant Basin was P. mangula and this species was synonymous with P. rhomboidea as a result of molecular studies.Morphometric measurements of both the identification keys and the literature indicate that all individuals caught from Mersin Bay are P. rhomboidea.Morphometric measurements and molecular analysis revealed that P. rhomboidea is a synonym of P. mangula.However, according to pictures in the literature of the species P. mangula is more reddish-bronze and P. rhomboidea is predominantly gray.
It was reported that the colors of the individuals which entered the first record in Visakhapatnam were reddish bronze and 42 soft rays were found on the anal fin and the species was given the name "mangula" (Russell, 1803).In 1829, Cuvier named this species as P. mangula.Koeda et al. (2014) reported that four species belonging to the genus Pempheris were distributed to the west of the Red Sea.Researchers also reported that among these species, P. mangula migrated to the Eastern Mediterranean Sea as a result of the opening of the Suez Canal.As characteristics of P. mangula separated from the other three species the size of the eyes; to be excessive dorso-ventral depth; be the blackish tip of dorsal fin; to be 49-60 pored scales along the lateral line were noted by Koeda et al. (2014).Genetic studies conducted in the same study indicated that P. rhomboidea is a synonym of P. mangula (Koeda et al., 2014).As a result of the morphological measurements, P. rhomboidea has 54-57 pores on the lateral line; 32-39 segmented and brown ray was found in anal fin (Azzurro et al., 2015).
In studies conducted in the Mediterranean Sea, Bilecenoğlu & Taşkavak (1999) from the Gulf of Antalya, Gücü et al. (1994) from Mersin Bay reported that the specimens of Pempheris was P. vanicolensis.In spite of this, Froese & Pauly (2018) allege that P. mangula and P. rhomboidea from the Pempheris genus distribute in the Mediterranean Sea.According to this literature P. mangula is a demersal tropical species whereas P. rhomboidea is a pelagic tropical species (Froese & Pauly, 2018).In previous studies, Pempheris individuals from the coast of Turkey has been reported as P. vanicolensis.The specimens reported in these studies may be P. rhomboidea.In this study, morphometric characters of each individual were measured in order to prevent possible errors in defining species (Table 1).Some meristic characteristics are D: VI, 9; A: III, 37-42 also support that the species in this study is P. rhomboidea.It is distinguished by the following characters: Dorsal spines: 6; Dorsal soft rays: 9-10; Anal spines: 3; Anal soft rays: 35-48.There is a blackish spot on pectoral fin base (Randall & Victor, 2015).
No morphometric measurements of P. rhomboidea were found in the literature.Randall & Bineesh (2014) determined morphometric measurements of P. sarayu.According to the researchers, P. sarayu and P. rhomboidea differ from each other in terms of the size of the eye, the pre-pelvic fin length, the fork of the caudal fin, the black color on the terminal of dorsal fin, body depth.They can be separated by a more grayish of P. rhomboidea and by a more copper of the P. sarayu.According to the comparison, P. rhomboidea caught from Mersin Bay was smaller than P. sarayu in terms of the specific morphometric measurements, and the given information in the literature was confirmed by our study (Table 2).P. rhomboidea was first recorded in the Aegean Sea by Akyol et al. (2017) which provided the first record of this species from Turkish coastal waters (Turan et al., 2018).The second record of P. rhomboidea from the Mediterranean coastal waters of Turkey was given with this study.At that time, occurrence of this species in the Northeastern Mediterranean Sea has also been reported from Coast of Cyprus (Iglésias & Frotté, 2015).The occurrence and extension of this species like other nonindigenous species are mostly due to global climate change and other anthropogenic factors as described by Turan et al. (2017).
and meristic characters of these individuals are given and sampling point of the species in the Mediterranean Sea is presented in Map (Figure1).Photographs of caught individuals are shown in Figures 2.

Figure
Figure 1.The red mark indicates the location where the specimens was caught Figure 1.The red mark indicates the location where the specimens was caught

Table 1 .
Some morphometric measurements of P. rhomboidea individuals

Table 2 .
Comparison of some morphometric measurements of P. sarayu and P. rhomboidea