Boleophthalmus

Abstract: Two allopatric populations of Boleophthalmus pectinirostris sensu lato are found in the western Pacific coast of East Asia and the Strait of Malacca in Malaysia. However, the species status of Malaysian populations remains debated. Mitochondrial ND5 gene (718 bp) and nuclear Rag1 gene (1395 bp) were used to reconstruct phylogenetic relationships among Boleophthalmus pectinirostris fishes by sampling 45 specimens from 11 locations in the northwestern Pacific. The results showed that Boleophthalmus pectinirostris fishes can be divided into two monophyletic sister groups: the East Asian and the Malaysian lineages. Species delineation using GMYC and *BEAST species tree analyses supports the inclusion of the East Asian and Malaysian lineages of Boleophthalmus pectinirostris sensu lato in two different species. A molecular clock estimated that the divergence time between these two lineages is 2.73 Ma. We concluded that Boleophthalmus pectinirostris sensu lato is a complex including two species. The East Asian lineage is Boleophthalmus pectinirostris sensu stricto, and the Malaysian lineage is a cryptic species (Boleophthalmus sp.). Our findings suggest that the split between Boleophthalmus pectinirostris sensu stricto and Boleophthalmus sp. can be attributed to geographic isolation due to low sea levels during glacials, and to barriers to gene flow determined by ocean currents during interglacials, in the late Pliocene.

Abstract: 1. 1. PK and LDH activities in the muscle of Periophthalmodon schlosseri and Boleophthalmus boddaerti were at least 100-fold higher than their respective activities in the liver. 2. 2. The ratio of PK:PEPCK in liver of B. boddaerti was smaller than that of P. schlosseri . 3. 3. PK:PEPCK ratios in both fishes were intermediate between those of aerobic and anaerobic organisms. 4. 4. MDH activity was higher than other enzymes assayed in the liver of both fishes. 5. 5. The ratios of LDH:MDH in the liver of both mudskippers were comparable to those of anaerobic organisms. 6. 6. AST was at least eight times more active than ALT in the liver of both fishes. 7. 7. In the muscle of these mudskippers, the aspartate content was significantly less than that of alanine. 8. 8. Exposure of these fishes to various experimental conditions led to changes in specific activities of PEPCK, LDH, AST and ALT.

Abstract: The species range of Boleophthalmus pectinirostris sensu lato includes two disjunctive areas, i.e., East Asia and Strait of Malacca in Malaysia along the northwestern Pacific coast. However, the species status of Malaysian populations remains disputed. Mitochondrial ND5 gene(718 bp) and nuclear Rag1 gene(1395 bp) were used to reconstruct phylogenetic relationships among Boleophthalmus pectinirostris fishes by sampling 45 specimens from 11 locations in the northwestern Pacific. The results showed that Boleophthalmus pectinirostris fishes could be divided into two major monophyletic groups, i.e., East Asian lineage and Malaysian lineage, and which together formed the sister-group relationship. Species delineation using the analyses of GMYC and *Beast species tree supports that East Asian lineage and Malasian lineage of Boleophthalmus pectinirostris sensu lato should be placed into two different species. Molecular dating revealed that the divergence time between East Asian lineage and Malaysian lineage of Boleophthalmus pectinirostris sensu lato was 2.73 Ma. We concluded that Boleophthalmus pectinirostris sensu lato was a complex, including two species. The East Asian populations is Boleophthalmus pectinirostris sensu stricto, and the Malaysian populations is a cryptic species(Boleophthalmus sp.). Our findings suggested that species split between Boleophthalmus pectinirostris sensu stricto and Boleophthalmus sp. was attributed to geographical isolation during lowing sea levels of ice ages and the barrier of gene flow induced by ocean currents during interglacial period in the late Pliocene.

Abstract: Eight species of mudskippers belonging to five genera were found to occur in the coastal areas of Langkawi Island. This includes a new record for Peninsular Malaysia i.e. Periophthalmus walailakae. This species was found to exist sympatrically with Periophthalmodon schlosseri, Periophthalmus novemradiatus, Periophthalmus gracilis, Periophthalmus spilotus and Boleopthalmus boddarti in the five study stations of the mangrove forest floor within the Kisap Forest Reserve, Bukit Tepoh and the riverine areas of Sungai Tepa that were sampled. Periophthalmus chrysospilos and Scartelaos histophorus were found along the sandy-beaches of Tanjung Rhu and mudflat of Kuah. The feeding habits were determined by the analysis of stomach contents of the genus Periophthalmus and Boleophthalmus using the method of percentages of occurrence and volumetric compositions. This was further illustrated graphically by interpretation of the Resultant Indices.

Abstract: A novel myxozoan parasite is identified and described from mudskipper, Boleophthalmus dussumieri, collected from a brackishwater ecosystem in Maharashtra, India. Ellipsomyxa boleophthalmi sp. nov. was found in the gallbladder of 58 of 60 fish examined (96.7%). The parasite formed disporous plasmodia that varied in size and shape, and the thin-walled, ellipsoidal and elongated myxospores measured 9.0–10.7 × 6.0–7.8 μm. The two, spherical polar capsules measured 2.7 μm in diameter and enclosed 3–4 coils of polar tubules. Histological observations of infected gallbladder revealed the attachment of disporous plasmodial stages of the parasite to the gallbladder wall with fine pseudopodia. Under the scanning electron microscope (SEM), the myxospores showed a distinct central sutural line and two distinct depressions on the opposite sides at the openings of polar capsules. SEM also revealed the engulfment of microvilli of gallbladder wall by pseudopodia of the plasmodial stages. Analysis of the partial fragment of the SSU rDNA region (1386 bp) showed less than 98% sequence similarity with the other reported Ellipsomyxa spp. In the phylogenetic tree, the present species formed as a distinct subclade within the major clade of Ellipsomyxa spp. The unique morphological and morphometric features of the myxospore, together with the molecular analysis, allowed us to conclude that the present myxozoan is a new species and is named Ellipsomyxa boleophthalmi sp. nov., after the generic name of the host. This is the first report on the occurrence of the genus Ellipsomyxa in B. dussumieri.