RUPLE: GOBIOIDEI 



587 



Table 151. Extended. 



Separated 



Dorsal surface Moderate Present 



Various other meristic characters are useful in the separation 

 of gobioid fishes. Branchiostegal rays number from 5 to 6. Myo- 

 meres/vertebrae range from 25 in Eviola infulata (Eleotridae) 

 to 76 in some of the microdesmids. 



Pigmentation.— V\%men\a\\on on the gas bladder and along the 

 ventral surface of the body are considered to be characteristic 

 of most gobioid larvae. Melanistic pigmentation in gobioid lar- 

 vae varies considerably, from the heavily pigmented gobiid .-15- 

 trabe lactisella (Fig. 310) to the sparsely pigmented gobioidids 

 (Fig. 311) and trypauchenids. Larval gobiids, eleotrids, and mi- 

 crodesmids generally have a moderate amount of pigmentation. 

 Pigmentation patterns are especially useful in separating larvae 

 at the generic and specific levels. 



Trypauchenid larvae, Ctenotrypauchen microcephalus and 

 Trypauchen microlepis (Fig. 311) generally lack pigmentation 

 except for two spots of pigment along the anterior poilion of 

 the caudal fin, while the gobioidids Taenioides cirratus and Go- 

 bioides hroussonneti totally lack pigmentation except for a pig- 

 mented gas bladder in Gobioides broitssonneti (Fig. 311). 



Pigmentation on the gas bladder is a prominent feature of 

 most known gobioids. The most common condition is pigment 

 on the dorsal surface, as in Microgohius thalassinus (Fig. 309) 

 and appears in most known gobioids. Dorsal and posterior gas 

 bladder pigment is known only in Gobionclhis species and Go- 

 bioides broussonneti (Figs. 310, 311). Trypauchen microlepis 

 (Fig. 311), Ctenotrypauchen microcephalus. and Taenioides cir- 

 ratus are the only known gobioid species which lack gas bladder 

 pigmentation entirely during their early development. 



The most pronounced pigmentation occurring in many eleo- 

 trids, gobiids, and microdesmids is that found along the ventral 



surface of the body, in the region of the gut and anal fin base. 

 Along the anal fin base, this pigmentation often occurs on in- 

 ternal as well as external surfaces. 



Pigmentation is often found in eleotrids, gobiids, and micro- 

 desmids on the caudal peduncle, along the dorsal surface of the 

 body, on the otic capsule, on the tip of the lower jaw, along the 

 mid-lateral posterior portion of the body, and on various fins. 

 While pigmentation often appears very similar, the subtle vari- 

 ations are frequently useful in the separation of larval gobioids. 



Contribution of laiA'ae to systematics 



Gobioid larvae have not been previously examined in terms 

 of contributing to the understanding of systematic relationships, 

 but I believe they will be of great use in the future. A preliminary 

 phenetic overview of gobioids based on characters available in 

 larvae (representing less than 5% of the total number of gobioid 

 species), presents some interesting groupings. Known larvae from 

 three eleotrid genera; Erotelis. Eleotris. and Dormitator seem 

 to form a cohesive group. Shared characters include: gross body 

 and head shape, short dorsal and anal fin bases, separated pel- 

 vies, gut length (~55% to 57% SL), dorsal gas bladder and 

 ventral pigmentation, late development of the first dorsal fin, 

 and separation of the two dorsal fins. Microdesmid larvae from 

 the genera Microdesmus. Cerdale. and Gunnellichthys. likewise, 

 all appear quite similar to each other, based on the following: 

 gross body and head shape, connected dorsal fins, long dorsal 

 and anal fin base, high vertebrae number, reduced pelvic and 

 pectoral fins, gas bladder and dorsal and ventral body pigmen- 

 tation. 



While the above mentioned eleotrid and microdesmid groups 

 appear fairly cohesive as well as distinct from other gobioids, 

 the family Gobiidae seem to be in some respects a catch-all 

 group. Currently, many diverse types of gobies are included 

 within the family Gobiidae (some 250 genera and well over 

 1,000 species). It is possible that larvae may present us with 

 additional characters that may help to better define the group. 

 The use of only adult characters has led many workers to debate 

 the rank of many taxa, for example Nelson's (1976) families 

 Trypauchenidae and Gobioididae have been relegated to 

 subfamilial status within the Gobiidae (Hoese, this volume) or 

 lower by other workers. Although the use of larval characters 

 alone will not define gobioid families they may allow a better 

 understanding of relationships. Known larvae of Trypauchen- 

 idae and Gobioididae exhibit characters that are distinctive or 

 unique to these taxa. Trypauchen microlepis has the shortest 

 and most acutely looped gut of any gobioid and is one of only 

 three species that lack gas bladder pigmentation (others are a 

 trypauchenid and a gobioidid). Pectorals are also more reduced 

 than in other gobioids. The long continuous dorsal fin and long 

 anal fin base are not shared among most gobioids. Gobioides 

 broussonneti also has a long continuous dorsal fin and long anal 

 fin base. It is one of only two known gobioid genera with dorsal 

 and posterior gas bladder pigment (the other being the gobiid 

 genus Gobionellus). and is one of the most sparsely pigmented 

 gobioids known. 



More descriptive work needs to be completed on the taxo- 

 nomic level of both adults and larvae before the full value of 

 ontogentic characters in gobioid systematics can be adequately 

 assessed. 



Gulf Coast Research Laboratory, East Beach Drive, Ocean 

 Springs, Mississippi 39564. 



