Overview

Comprehensive Description

[[ Genus Macroramphosus ZBK ]]

Introduction

The family Centriscidae includes small-sized gregarious fishes that are characterized by a laterally compressed body, head with a long tubular snout and a small terminal mouth (Ehrich, 1986). In the Mediterranean Sea, this family is represented by a single genus, Macroramphosus ZBK . Several authors claim that the genus is monotypic, represented only by M. scolopax , and have defended the synonymization of the two species (D’Ancona, 1933; Ehrich, 1975, 1976, 1986; Fischer et al., 1987). The existence of phenotypically intermediate individuals, and the difficulty in collecting small sized M. scolopax (Linnaeus) specimens has led some authors to consider M. gracilis as a juvenile form of M. scolopax (Assis, 1992). However, the deep-bodied M. scolopax and the slender-bodied M. gracilis have been recognized as two valid species in studies carried out at the Atlantic Ocean; this viewpoint is based on observations of distinct differences in age and growth (Brethes, 1979; Borges, 2000), reproductive biology (Arruda, 1988), morphology (Assis, 1992, 1993) and feeding habits (Matthiessen et al., 2003). Recent investigations on the larval development of specimens of Macroramphosus ZBK from Japan also revealed the occurrence of two distinct species (Kuranaga & Sasaki, 2000; Miyazaki et al., 2004).

Although previous records of M. gracilis are available from various parts of the Mediterranean Sea, there was no agreement among authors on the validity of the species. This paper documents the occurrence of M. gracilis as a valid species in the Mediterranean Sea, and compares the species with M. scolopax . Morphometric characters that distinguishes the two species are also presented.

  • Murat Bilecenoglu (2006): Status of the genus Macroramphosus (Syngnathiformes: Centriscidae) in the eastern Mediterranean Sea. Zootaxa 1273, 55-64: 55-56, URL:http://www.zoobank.org/urn:lsid:zoobank.org:pub:489D488F-6F25-4950-8FA4-8FDBF4C8AB00
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[[ Genus Macroramphosus ZBK ]]

Discussion

A total of 16 proportions of morphometric measurements were analyzed in this study. Five parameters (SnL/SL, HL/SL, PBL/SL, SnL/HL, MBD/LBDS) were similar between the two species, while a statistically significant difference was found for the remaining 11 characters (Table 1).

Eye diameter measurements and its proportion in relation to HL, D1-D2 and PHL gave significant results. The most striking ratios were found to be as ED/D1-D2 (eye diameter greater than the length between dorsal fins in M. scolopax versus smaller in M. gracilis ) and ED/PHL (postocular head length smaller than the eye diameter in M. gracilis , larger in M. scolopax ). These ratios were previously used in identification keys to Mediterranean centriscid species by Bauchot & Pras (1980) and Tortonese (1970), respectively. The mean ED/HL indicates a smaller eye diameter for M. gracilis (16.74%), when compared to M. scolopax (19.04%).

In several previous studies, length of dorsal spine (LDS) was considered as a very important character to discriminate Macroramphosus ZBK spp. Our findings revealed a slight overlap in the range values of LDS/SL and LDS/PBL; however, their mean values indicate a clear difference between the two species, where M. gracilis has a shorter dorsal spine when compared to M. scolopax . Similar results were obtained from studies conducted in the Atlantic and Pacific Oceans (Brethes, 1979; Assis, 1992; Mathiessen et al., 2003; Miyazaki et al., 2004). The eastern Mediterranean specimens of M. gracilis had conspicuously weaker dorsal spines, which does not reach to caudal base, as also noted by Günther (1889) and Smith (1965).

Maximum body depths of the two species differ significantly. MBD/SL and MBD/ PBL ratios were smaller for M. gracilis , as a result of the slender body shape. Similar results were obtained by Brethes (1979), Assis (1992) and Miyazaki et al. (2004). We determined that body depth is found 3.71-4.60 times in SL of M. scolopax , and 4.53-5.39 times in M. gracilis , in agreement with the findings of Tortonese (1970).

Apart from metric measurements, some other distinctive morphological characters were determined between the two species. The occipital crest located at the anterior part of eye bears prominent spinules in two or three rows in M. scolopax , but no spinule was observed on the occipital crest of M. gracilis (Figure 3). D’Ancona (1933) reported that, both supraorbital and occipital crests are visible in specimens with 3 mm length, becoming conspicuous in fish larger than 9 mm. Thus, a change in occipital crest structure through developmental stages between juveniles and adults is not expected, and this character can be used in distinguishing the two centriscid species.

The relatively straight ventral body profile of M. gracilis is another distinctive feature, which was also mentioned in previous studies (D’Ancona, 1933; Miyazaki et al., 2004). The well-developed elevated scutes between the pelvic and anal fins of M. scolopax are conspicuous, while in M. gracilis scutes are either absent or represented by a single weakly developed scute (Figure 4). This character was stated to be diagnostic for Japanese Macroramphosus ZBK spp. (Miyazaki et al., 2004), which seems to be also valid for Mediterranean species.

The number of spinules along the posterior margin of D2 spine of M. gracilis tends to be lower than M. scolopax (0-14 vs 14-23 spinules). The less denticulated dorsal spine structure of M. gracilis was also indicated by Günther (1889) and Tortonese (1970). Miyazaki et al. (2004) examined dorsal spine denticulation based on Japanese coast centriscids, where a degeneration of spinules by 50 mm SL was noted for M. gracilis - which is not the case in Mediterranean specimens. Since both centriscid species are known to be sympatric (i.e. Assis, 1992), the assumption indicated by Matthiessen et al. (2004) that ecological differences in diet composition and habitat use of sympatric species promotes morphological diversification should be concerned.

Macroramphosus scolopax and M. gracilis are two morphologically similar species with some overlapping metric and meristic measurements, and no single character provides precise (Assis, 1992; Mathiessen et al., 2003). Based on the results of our study, the following combination of characters should be used in distinguishing Mediterranean specimens of M. gracilis from M. scolopax : first dorsal fin originating before anus; second spine of first dorsal not extending beyond second dorsal fin base; length between two dorsal fins greater than the eye diameter; ventral scutes not protruding; less developed projecting scute between pelvic and anal fins.

  • Murat Bilecenoglu (2006): Status of the genus Macroramphosus (Syngnathiformes: Centriscidae) in the eastern Mediterranean Sea. Zootaxa 1273, 55-64: 60-62, URL:http://www.zoobank.org/urn:lsid:zoobank.org:pub:489D488F-6F25-4950-8FA4-8FDBF4C8AB00
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Ecology

Habitat

Depth range based on 806 specimens in 4 taxa.
Water temperature and chemistry ranges based on 561 samples.

Environmental ranges
  Depth range (m): 0 - 80000
  Temperature range (°C): 3.096 - 26.764
  Nitrate (umol/L): 0.286 - 28.203
  Salinity (PPS): 33.843 - 38.781
  Oxygen (ml/l): 2.268 - 6.323
  Phosphate (umol/l): 0.094 - 1.945
  Silicate (umol/l): 0.677 - 27.515

Graphical representation

Depth range (m): 0 - 80000

Temperature range (°C): 3.096 - 26.764

Nitrate (umol/L): 0.286 - 28.203

Salinity (PPS): 33.843 - 38.781

Oxygen (ml/l): 2.268 - 6.323

Phosphate (umol/l): 0.094 - 1.945

Silicate (umol/l): 0.677 - 27.515
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
                                        
Specimen Records:79Public Records:29
Specimens with Sequences:74Public Species:1
Specimens with Barcodes:67Public BINs:3
Species:3         
Species With Barcodes:3         
          
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Barcode data

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Locations of barcode samples

Collection Sites: world map showing specimen collection locations for Macroramphosus

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Wikipedia

Macroramphosus

The snipefishes (genus Macroramphosus) are species of fishes found in tropical and subtropical oceans at depths down to 600 metres (2,000 ft). According to FishBase, they are part of the family Centriscidae, but some authorities split that family, in which case the genus Macroramphosus is in the family Macroramphosidae. They have long second spines on their dorsal fins and tiny mouths at the tip of their greatly elongated snouts. Their bodies are more streamlined than in the related bellowfishes. They reach a maximum length of about 20 cm (7.9 in), and are silvery or reddish in colour. They are sometimes found in large schools.

Species[edit]

Currently, two recognized species are placed in this genus:[1]

References[edit]

  1. ^ Froese, Rainer, and Daniel Pauly, eds. (2012). Species of Macroramphosus in FishBase. October 2012 version.
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