A Study On Gill Comparative Morphology Of Seventeen Oxudercine Gobies From Southeast Asia And Australia

Oxudercine gobies in subfamily Oxudercinae (Perciformes:Gobiidae) widely habitat in the mudflat and mangrove ecosystems of the Indo-Pacific and the Atlantic coast of Africa, which are small in individuals. Most species of this subfamily present different degrees of adaptation to the amphibious lifestyle, which have owned the entire intertidal gradient, from water to land, and their gills have developed many adaptive changes as the main respiratory organ. Now, information regarding comparative morphology and ecological morphology of the gills is largely scanty for the fishes in the subfamily Oxudercinae. The gill morphology and histology of six genus (Apocryptodon, Pseudapocryptes, Scartelaos, Boleophthalmus, Periophthalmodon and Periophthalmus) including 17 species of Oxudercinae from Australia and Southeast Asia were studied. The main results are as follows:1. Interspecific variations of five gill parameters (e. g. total number of filaments (F), average filament length (Lave), average number of secondary lamellae (one side of filaments) (n,/mm), average bilateral area of secondary lamellae (A) and relative gill area (G)) are small in 15 Oxudercine gobies for the morphological measurements, except for relative gill area of P. novaeguineaensis, P. chrysospilos, P. novemradiatus, P. argentilineatus and Pn. Septemradiatus, and average filament length of Scartelaos histophorus and Periophthalmus novaeguineaensis. Of the five gill parameters, relative variations of total number of filaments (F), average number of secondary lamellae (one side of filaments) (n,/mm) are smallest among individuals.2. Oxudercine gobies for the morphological measurements among genus are of significant difference (P<0.05) in total number of filaments (F), average filament length(Lave), average number of secondary lamellae (one side of filaments) (n,/mm), average bilateral area of secondary lamellae (A) and relative gill area (G).3. Measurements of gill parameters were carried out on five mudskippers, Boleophthalmus boddarti, Scartelaos histophorus, Periophthalmus spilotus, Periophthalmus novaeguineaensis and Periophthalmus chrysospilos were analysed in relation to body weight using logarithmic transformations (logY=loga+blogW), and the gill parameters (Y) were significantly correlated with the body weights (W) in the five species (P<0.05), except relative gill area of Periophthalmus chrysospilos. Meanwhile, comparing the individuals of the same weight, the values of total number of filaments, total filament length (mm), average number of secondary lamellae/mm (on one side of filaments), total gill area (mm2) and relative gill area (mm2/g) for S. histophorus were the largest, those for B. boddarti were at a medium level and those for P. novaeguineaensis, P. spilotus and P. chrysospilos were the smallest.4. The filament length at the first gill arch is shorter compared with the other gill arches.There are great differences in the filament length of anterior hemibranch and posterior hemibranch at the first gill arch for Beleophthalmus boddarti, Scartelaos histophorus, Scartelaos gigas, Pseudapocryptes elongatus, Apocryptodon punctatus.5. The inside diameter for capilliary of secondary lamellae for Apocryptodon punctatus is the smallest (6.15μm), and that for Periophthalmus chrysospilos is the largest (11.81μm). The inside diameter for capilliary of secondary lamellae is in accordance with Apocryptodon< Pseudapocryptes< Scartelaos< Boleophthalmus< Periophthalmodon and Periophthalmus, except that the inside diameter for capilliary of secondary lamellae for B. dussumimeri is larger and those for P. novaeguineaensis is smaller.6. The density of capilliary capilliary for Apocryptodon punctatus is the largest coming up to 0.138 (/μm). The density of capilliary capilliary among 5 genus is according with Apocryptodon> Pseudapocryptes> Scartelaos> Boleophthalmus> Periophthalmus. There are a few differences in the same genus for the density of capilliary.7. The thickness of secondary lamellae among oxudercine gobies is assumed to be: Apocryptodon< Pseudapocryptes< Scartelaos< Boleophthalmus< Periophthalmodon and Periophthalmus. The thicknesses of interlamellar cell mass in Boleophthalmus and Periophthalmodon species are larger compared with other genera.