International Journal of Marine Science, 2016, Vol.6, No.16 1
-
8
4
or lateral surface of axial corallites. The way of
budding and shape of a corallite and its calice are
noticeably different in every species. Growth and the
relationship between axial and radial corallites provide
the opportunity for
Acropora
species to form branched
colonies especially well in this genus. Due to such
properties, they stand apart from the other genera and
occupy the key position among the other scleractinian
of a reef ecosystem.
Thus, a group of species, having a pronounced
morphological status (absence of axial and radial corallites,
inability to form branched colonies), peculiarities of
reproduction (bearing planula up to a polyp state) and
occupying specific ecological niches, should be
distinguished taxonomically as well. That is why it is
better to consider corals of subgenus
Madrepora
(
Isopora
)
Studer (1878), synonyms Brook (1893),
Acropora
(
Isopora
) Veron and Wallace (1984), and subgroup
Isopora
(Nemenzo, 1967) within the independent genus
Isopora
Studer, 1878 (Latypov, 1992, 2014).
Latypov also showed that constantly found two forms
of
Isopora
– incrusting and massively branching
distinctly separated and on other grounds. The first is
the corallites are shallow, chaotic densely adjoin to
each other (65-72 per unit area), covered by numerous
spines. The second is the corallites are larger (23-36
per unit area), poorly oriented in rows and separated
from each other. They were described as
Isopora
cuneata
and (Figure 1). Below you will see that these
are two genetically isolated species. K. Wallace
pointed out that some questionable types of
Acropora
better consider comprising subgenus
Acropora
(Isopora)
Studer, 1878, to elevate the status of the
genus
Isopora
by T. Randall (Randall, 1981), but so
far they have not come to a final decision (Wallace,
1997)
Later, Wallace and co-authors, having morphological
and genetic studies of different corals
Acropora
and
Isopora
confirmed the statements of Latypov. They
showed that the species
A. palifera, A. togianensis
and
A. cuneata
except bearing polyp inside known, instead
of broadcast spawning external fertilization, (as all
Acropora
) differ from each other, and from other
Acropora
on mitochondrial knowledgebase b (cytb)
and nucleic histones 2a and 2b (h2ab) group A. They
formally proposed the species
Acropora (Acropora)
togianensis
A. (Isopora) palifera
and
(A) (Isopora)
cuneata
classified as genus
Isopora
Studer , 1878
(Wallace et al., 2007).
Figure 1. Form colonies of corals of the genus
Isopora
. 1-
I. cuneata
, 2-
I. palifera
, clearly
visible differences in the sizes of the corallite
and their location.
Figure 1 Form colonies of corals of the genus
Isopora
. 1-
I.
cuneata
, 2-
I. palifera
, clearly visible differences in the sizes of
the corallite and their location
3 Terminology and Morphological-taxonomic
Signs
Since acroporids are one of the most complicated
coral groups, it is necessary to pay special attention to
peculiarities of terminology and construction of
skeletal elements, used in identification and
systematization of corals of this family. Acroporids do
not have or have rudiments of many skeleton elements,
which are usually used in species identification and
investigation of variability of most other corals:
columella, dissepiments, and septal structures. That is
why colony shape, modes of branching, features of
