446 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



<:^^ 



Fig. 241. Hypothesis of cottoid relationships modified from Washington and Richardson (MS). 



Washington and Richardson's (MS) hypothesis of relation- 

 ships among the other cottoids studied is shown in Fig. 241. 

 Characters observed in the cottoid families, Cottidae (broad 

 sense of Washington and Richardson, MS), Agonidae, and Cy- 

 clopteridae, are derived relative to both the scorpaenids and 

 hexagrammids. The cottids, agonids, and cyclopterids share four 

 apomorphic characters, none of which is restricted to the larval 

 period. These include: 1) pleural ribs absent or restricted to the 

 posterior three abdominal vertebrae; 2) epipleurals independent 

 or sessile; 3) small first anal pterygiophore; and. 4) no anal 

 spines. 



The cyclopterids (including lipandids) appear to be a distinct 

 family defined by a modified ventral sucking disc and are the 

 sister group of the cottids and agonids. (See Able, Markle and 

 Fahay, this volume, for discussion of cyclopterid relationships). 



The cottids and agonids share three derived characters: 1 ) the 

 first anal pterygiophore is simple; 2) there are no supernumerary 

 anal elements; and 3) the haemal spine of preural centrum 2 is 

 enlarged. Again, none of these characters is unique to the larval 

 period. 



Among the 28 genera of cottids examined, Washington and 

 Richardson (MS) recognized eight monophyletic groups which 

 are defined by one or more apomorphic characters. Rhampho- 

 cottiis, a monotypic genus, is characterized by four distinctive 

 autapomorphies, two of which are larval characters. Rhanipho- 

 cottus larvae possess a unique body shape with an extremely 

 long snout to anus length (>60% SL) and deep body shape (29- 

 40% SL). Rhamphocottus larvae also possess only one preoper- 

 cular spine. Other workers have also found Rhamphocoitits to 



deviate from other cottids and have placed it in its own family 

 (Gill, 1888; Johnson, 19 18; Jordan, 1923;Bohn, 1934;Taranets, 

 1941). 



Hemtlepidotus and Scorpaenichthys form another cottid group 

 and are defined by five autapomorphies, three of which are 

 unique to the larval period. First, members of both genera de- 

 velop heavy, pitted dermal bone on the cranium which forms 

 early in larval development. As the bone develops, ossification 

 proceeds unevenly with small pockets of bone apparently re- 

 sorbed forming pitted areas, while surrounding areas are thick- 

 ened. Second, larvae develop broad supraocular bony shelves 

 which project laterally over the orbit. Third, the dorsalmost 

 radial of the pectoral fin is reduced in size and becomes fused 

 or nearly fused to the scapula during larval development. 



These three characters are not present in any other cottids 

 examined. Although both Scorpaenichthys and Hcimlepidotus 

 have been postulated as "primitive" cottids by workers studying 

 adults, they have not previously been considered closely related 

 to each other. 



The remaining cottids and agonids share four additional de- 

 rived characters: 1) neural spine of PU 2 elongate; 2) neural 

 spine of first vertebra absent; 3) upper and lower hypural plates 

 fused to each other and fused to the urostyle; and. 4) the first 

 neural arch is unfused, rather it forms in a broad U-shape. The 

 last character is a larval feature found only in these taxa. 



Five additional generic groups are defined by one to six au- 

 tapomorphies. Although these five groups contain the majority 

 of cottid genera, no synapomorphies were found which united 

 these groups and yet separated them from the agonids. The 



