Shad - Systematics

Systematics

Systematics of shads is complex. The genus inhabits a wide range of habitats, and many taxa are migratory. There are also a few land-locked forms, one from Killarney in Ireland and two from lakes in northern Italy. There are species native to the Black Sea and Caspian Sea, as well as the Persian Gulf. Alosa species of the Caspian are systemically characterized by the number of rakers on the first gill arch by some scientists. They are classified as being "multirakered," "mediumrakered," or "oligorakered." The multirakered are primarily plankton feeders, the oligorakered have large rakers and are predators, and the mediumrakered generally possess a mixed diet. Most current species of the Alosa genus in North America can be found in Florida, although Florida may not be the only place that these species are found.

Morphology is notoriously liable to adapt to changing food availability in these fish. Several taxa seem to have evolved quite recently, making molecular analyses difficult. In addition, it appears as if hybridization is a factor to be reckoned with when researching shad phylogeny.

  • The Founding Fish (2002) ISBN 0-374-10444-1.

Nonetheless, some trends are emerging. The North American species except the Atlantic shad can probably be separated in a subgenus (or even genus) Pomolobus. On the other hand, the proposed genus (or subgenus) Caspialosa for the Caspian Sea forms is rejected due to paraphyly.

  • Alosa aestivalis (Blueback Herring)
  • Alosa agone (Agone)
  • Alosa alabamae (Alabama shad)
  • Alosa algeriensis (North African shad)
  • Alosa alosa (Allis shad)
  • Alosa braschnikowi (Caspian marine shad)
  • Alosa caspia
    • Alosa caspia caspia (Caspian shad)
    • Alosa caspia knipowitschi (Enzeli shad)
    • Alosa caspia persica (Astrabad shad)
  • Alosa chrysochloris (Skipjack shad)
  • Alosa curensis (Kura shad)
  • Alosa fallax (Twait shad)
  • Alosa immaculata (Pontic shad)
  • Alosa kessleri (Caspian anadromous shad)
  • Alosa killarnensis (Killarney shad)
  • Alosa macedonica (Macedonia shad)
  • Alosa maeotica (Black Sea shad)
  • Alosa mediocris (Hickory shad)
  • Alosa pseudoharengus (Alewife)
  • Alosa sapidissima (American shad)
  • Alosa saposchnikowii (Saposhnikovi shad)
  • Alosa sphaerocephala (Agrakhan shad)
  • Alosa tanaica (Azov shad)
  • Alosa vistonica (Thracian shad)
  • Alosa volgensis (Volga shad)

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