FISHERY BULLETIN. VOL. 71, NO. 3 



Table 3. — Distinguishing features of larvae of Etropus microsiomus and Citharichthys arctifrons 



from the Chesapeake Bight.' 



Character 



Eiropus microstomus 



Cilharichthys arctifrons 



Pigmentotion: 

 Head 



Abdomen 



Tail 



AAorphology: 

 Size at 



metamorphosis 

 Preopercular 



spines 

 Elongated fin 



rays 



Body depth 



Meristics: 



Anal fin rays 

 Vertebrae 



Internal spot below hindbrain 



(8 mm). 

 Stellate melonophore on operculum 



(10-11 mm). 

 1-2 stellate melanophores on pectoral fin. 

 Internal spots along notochord (4 mm). 

 3 postanal horizontal bars (3-4 mm). 

 Internal spots along length of notochord (4 mm). 



2 prominent ventral clusters between anus and postanal 

 bars (4 mm). 



10-12 mm. 



Prominent from 2.5-8 mm, disappear by 10 mm. 

 None. 



Depth at anus/SL and depth behind onus/SL usually greater for 

 E. microstomus than C. arctifrons of equal size. 



Depth behind onus/depth at onus related to SL greater for 

 E. microstomus than C arctifrons of equal size (8 mm). 



Usually <60 (8 mm) 

 10 abdominal 

 24-25 caudal (9 mm) 

 including urostyle 



No. 

 No. 



No. 



No. 



Similar (4-5 mm). 



Internal spots along 

 notochord only in 

 region of postanal bar 

 (5 mm). 



No. 



13- 15 mm. 



None. 



3 elongated anterior dorsal 



rays (4-5 mm to 



11-12 mm). 



Usually >60 (10 mm). 

 10-1 1 abdominal. 

 26-28 caudal (10 mm) 

 including urostyle. 



' Sizes in parentheses indicate size at which the character is attained. 



deviation of ±0.04 mm between major and 

 minor axes. The eggs had a smooth surface; no 

 oil globule was apparent although most bothid 

 eggs have a small one. Diameters of these C. 

 arctifrons eggs ranged from 0.70 to 0.82 mm 

 {X = 0.74 mm). Diameters of fertilized eggs 

 may differ. 



The smallest larvae examined of both species 

 were 2.3 mm. At that size, a small amount of 

 yolk material is still present. These larvae are 

 similar in appearance to the 2.5-mm larvae 

 (Figure 2) described in the next section. No 

 additional information is available on earlier 

 stages. Because larvae of the two species are 

 comparable in size (under 5 mm) and develop- 

 mental stage, they probably hatch at about the 

 same size, estimated to be about 2 mm. 



DEVELOPMENT OF 



E. MICROSTOMUS AND 



C ARCTIFRONS - 



LARVAE TO ADULTS 



Descriptions of the development of E. micro- 



stomus and C. arctifrons are patterned after 

 workers who followed the dynamic approach, 

 e.g., Ahlstrom and Ball (1954), Ahlstrom and 

 Counts (1955, 1958), Kramer (1960), Moser 

 and Ahlstrom (1970), and others. Three major 

 aspects of development are discussed: pigmen- 

 tation changes, morphological changes, and 

 osteological changes. Descriptions are based 

 primarily on the left (eyed) side. A length des- 

 ignation of 4 mm implies a range of values from 

 4.0 to 4.9 mm. The term metamorphosis is 

 used to describe the period of eye migration 

 until the right eye rests in its final position on 

 the left side of the head. The term larva is used 

 to define all stages from yolk sac absorption 

 until all fins are formed after completion of 

 metamorphosis. The term juvenile refers to 

 all stages from completion of fin formation to 

 adult. Comparative development is followed 

 through to the adult stage. 



Pigmentation Changes 



Changes in pigmentation of E. microstomus 

 and C. arctifrons are described as they occur 



740 



