Key to the Families of Marine, Estuarine, and Freshwater Bony Fishes of the Southeastern United States

Key to the Families of Marine, Estuarine and Freshwater Bony Fishes of the Southeastern United States

  • Modification: The key is a modified version of J.C. Briggs' unpublished manuscript, based on the work of Jordan and Evermann.
  • Note on Families: Families marked with a single asterisk () mainly occur outside the 200 m bottom contour. Families marked with two asterisks (*) indicate species that are introduced and are not present in the subset of unknowns.

Pelvic Fins Classification

  • Pelvic Fins Present
  • Pelvic Fins Absent

Pelvic Fins Present Characteristics

  1. Pelvic fins present, thoracic, subjugular, or jugular
  2. Pelvic fins present, abdominal
    • Back with an adipose fin: This type has a single rayed dorsal fin behind the adipose fin.
    • Back without adipose fin: Two categories based on head features:
    1. Head with 4 to 8 long barbels around the mouth and nostrils; body scaleless; a single spine in each pectoral fin and dorsal fin. (Examples: Ictaluridae, Ariidae)
    2. Head without barbels:
      • Sides of body
        1. Without photophores or luminous glands; no barbel at throat…
        2. With photophores
          • Body scaleless (naked); very strong teeth, some fang-like…
          • Body scaly:
          • Dorsal fin very long and high, occupying nearly the full length of the back (Example: Alepisauroidae)
          • Dorsal fin short; median or posterior (Example: Evermannellidae*)
          • Pseudobranchiae presence
            • Present or absent; several consequences relating to the structure and feeding nature of the fish.

Pectoral Fins Examination

  • Pectoral fins of typical form: Teeth incisor-like or rudimentary; pseudobranchiae absent.
  • Pectoral fins not of typical form
    • Undivided subhumeral: Pseudobranchiae absent.
    • Pectoral rays elongate: Arranged in two groups.

Photophores and Teeth Form

  • Ventral photophores:
    • In discrete clusters of two or more light organs joined at their bases (Examples: Sternoptychidae*)
    • All photophores separate, not joined at their bases (Example: Chauliodontidae (Stomiidae)*)
  • Teeth differentiation:
    • Premaxillae forming entire margin of the upper jaw; body scaly; opercles complete (Example: Gonostomatidae, Photicthydidae*)
    • Premaxillae not forming entire margin, with scales deciduous or absent…

Elongation and Caudal Fin Variations

  1. Body elongate:
    • Snout pointed, barracuda-like; photophores very small (Example: Paralepididae*)
    • Snout not much produced; conspicuous photophores (Example: Myctophidae)
  2. Dorsal fin configurations
    • Single dorsal fin made up of rays without free spines or followed by finlets (Example: Aulostomidae)
    • Two dorsal fins the anterior entirely spinous, the posterior chiefly soft rays.

Body Traits and Scale Types

  • Body features:
    • Six series of shield-like scales (scutes); mouth inferior, toothless, preceded by 4 barbels… (Example: Acipenseridae)
    • Scales types vary (cycloid, ganoid).
  • Body behavior: Present major markers and distinctions within habitat types.

Detailed Descriptions of Various Families and Characteristics

Notable Families

  • Ictaluridae, Ariidae, Argentinidae: Scales, teeth adaptation, and characteristics of pectoral fins.
  • Sternoptychidae, Chauliodontidae (Stomiidae): Details relating to photophores and anatomical structure.
  • Albulidae, Clupeidae: Differences in gill arches, mouth types, and other morphological characteristics.
  • Cichlidae: Introduced species with distinct features (marked with **).

Appendages and Body Structure

  • Gill Structures:
    • Openings in front of the pectoral fin…
    • Openings behind the pectorals… (Example: Gobidae, Triglidae)
  • Tail and Fin Structures:
    • Highly diverse; finlets and modifications in dorsal and anal fins.

Pelvic Fins Absent Classification

  1. Premaxilla and Maxilla features: Absent or immovably united, indicating significant evolutionary adaptations like elongation and various fin structures.
  • The provided detailing includes various families with their specific ranges of characteristics and adaptations, allowing identification and classification in biological studies relating to marine, estuarine, and freshwater environments of the Southeastern United States. The format enables the comprehensive description and classification of fish families pivotal for ecological, environmental, and research purposes. Other information includes how these features influence behaviors, habitats, and interactions in aquatic ecosystems.