Taxonomy
Since the last two centuries, the classification of decapods, particularly
of crabs have passed through a series of changes. Earlier, Latreille
(1802) divided Decapoda into the long-tailed Macrura and short-tailed
Brachyura. Later, Milne Edwards (1834) created a third decapodan division
called the Anomura. Milne Edwards then divided brachyuran crabs into
4 groups
1. Oxyrhynques
(spider crabs),
2. Cyclometopes
( round fronted crabs )
3. Catometopes
(square fronted crabs)
4. Oxystomes
(sharp fronted crabs).
De Haan
(1833-49), based on mouth parts, regrouped the brachyurans into 2
main divisions Oxystomata and Brachygnatha. Later Dana (1852 a, b,
c) modified the scheme of Milne Edwards and classified Brachyura into
5 sub-tribes namely
1. Maioidea
2. Cancroidea
3. Corystoidea
4. Graposidea
5. Leucosoiidea.
Then
Miers (1886) grouped Brachyura into 4 sub-tribes as
1. Oxystomata
or Leucosiidea
2. Oxyrhyncha
or Maioidea
3. Cyclometopa
or Cancroidea
4. Catometopa
or Ocypodiidea. Alcock (1895-1900) followed the above classification
with slight modifications. In the meantime Bouvier (1896) classified
Brachyura into 5 tribes as
1. Dromiacea
2. Oxystomata
3. Corystoidea
4. Brachyrhyncha
5. Oxyrhyncha.
Later
Borradaile (1907) classified the Tribe Brachyura into 3 sub-tribes
as
1. Dromiacea
2. Brachygnatha
3. Oxystomata
Borradaile's
general scheme had been widely accepted by zoologists and Balss (1957)
followed the same with slight modifications. In his classification,
the Tribe Brachyura had 4 sub-tribes as
1. Dromiacea
2. Oxystomata
3. Brachygnatha
4. Hapalocarcinoidea.
Glaessner's
(1969) classification included 5 sections namely
1.
Dromiacea
2.
Oxystomata
3.
Oxyrhyncha
4.
Cancridea
5.
Brachyrhyncha.
Later
Sakai (1976) classified Brachyura into 7 sub-sections as
1.
Dromiacea
2.
Gymnopleura
3.
Oxystomata
4.
Oxyrhyncha
5.
Corystoidea
6.
Brachyrhyncha
7.
Hapalocarcinidea.
Guinot
(1977, 1978) proposed a new classification of adult Brachyura based
primarily on the position of female and male genital openings. In
her classification, she proposed:
- Podotremata:
Families in which both female and male openings are coxal.
- Heterotremata:
Families in which the female genital openings are all sternal, whereas
at least some representatives have the male openings coxal.
- Thoracotremata:
Families in which both the female and male openings are always sternal.
Rice
(1980) proposed brachyuran classification based on larval characteristics.
Nowadays, Guinot's classification is widely followed and it received
much support from Rice (1980) also. In the present study, brachyuran
crabs of the west coast, India are arranged as per the classification
of Guinot ( 1977, 1978).
