Author : Corral, Jonel M.

Summary : The body morphology of Gulaphallus bikolanus collected in Agos river, Guinobatan river, and Sagñay river was examined for morphological variations. For site variation, analysis of variance (ANOVA) revealed significant difference (p < 0.05) in metric characters including head length, upper jaw length, occipital distance, body depth, ventral fin base, second dorsal fin base, caudal peduncle, pectoral fin length, pre-orbital distance, ventral caudal distance, ventral ray length, second dorsal ray length, and second pre-dorsal fin length except for eye diameter and post-orbital length (p > 0.05). Sex variation showed significant difference (p < 0.05) in head length, upper jaw length, occipital distance, body depth, pectoral fin length, pre-orbital distance, eye diameter, post orbital length, ventral caudal distance, ventral ray length, and second dorsal ray length except for ventral fin base, second dorsal fin base, caudal peduncle, and second pre-dorsal fin length. Body depth and fin related sizes (ventral fin base, ventral caudal distance, pectoral fin length, ventral ray length, second dorsal ray length, second predorsal fin length) were the main contributor to variance among populations based on Principal Component Analysis (PCA) and Canonical Variate Analysis (CVA). Male was observed to have longer body length (25.25±2.06mm) while female has much deeper body (22.65±1.11mm) which could suggest roles in reproduction. Variations in fin sizes
aids in stability and control during swimming and may also help males in positioning themselves during spawning in order to maximize fertilization success. Symmetrical body was most observed in Guinobatan river which plays an important role in sexual selection. Length-weight relationship between total weight and TL, FL, and SL had a regression model explained 60-80% of the variance for female while 77-89% for male. Variation on the meristic counts was evident but not significant based on ANOVA. Different cells stages of spermatogenic were identified which include spermatogonia (SG), spermatocytes (SC), spermatids (ST) and sperm (SP). Spermatogonia are located along the ventral edge of the testis. Progressive stages of sperm cell maturation and
spermatozeugmatum were observed in testicular morphology while the female gonad has a cavity/lumen filled with mature sperm which was transferred from male toxactinium.