Introduction
Freshwater
prawns mainly refer to certain species of Caridean (Decapoda: Caridea).
It is a highly
species-rich
group with a long taxonomic history, but at the same time its taxonomic
status is controversial. There are about 770–800 Caridea species in
freshwater, accounting for about one-fifth of the shrimp described
(De Grave et al., 2015 ). At
present, freshwater shrimps are only exist in 7 families of 38 currently
Caridea families (De Grave, Li,
Tsang, Chu, & Chan, 2014 ). Among them, the two families of Atyidae
and Palaemonidae are quantitatively dominate, comprising 443 and 300
species respectively, which account for 97.4% of all freshwater shrimp
species (De Grave et al., 2015 ).
Shrimp play an important role not only as an important component of
biodiversity but as a very good source of animal protein for people. In
addition,
freshwater
shrimp has high economic value, nutritional value and research
significance (Holthuis, 1980 ;New & Nair, 2012 ). Therefore, the
taxonomic identification and species identification of shrimp is one of
the most important tasks for all kinds of related biological research
and fishery resource conservation and
management(Shen, Guan, Wang, & Gan,
2016 ) .
There have been many studies on freshwater prawn fauna, but it is poorly
known of Henan Province, China. So far, 8 species of shrimps have been
reported. The survey used traditional morphological recognition methods
to identify and morphologically describe 352 samples of 8 species that
from 15 sampling points (F. Wang,
1989 ). Henan province is located in inland, there are four major river
systems, such as the Yellow River, the Yangtze River, the Huaihe River
and the Haihe River. But studies on the freshwater prawns of this area
are rather scanty. In view of the above, it is of great significance to
enrich shrimp related researches in Henan province to append the list of
shrimp species and assess the biodiversity of this area.
The
study of species diversity is the basis of all biological research, but
at the same time it is also a huge challenge and a harsh
burden(P. D. Hebert, Cywinska, Ball,
& deWaard, 2003 ). As the main method of species diversity research,
traditional morphological identification has high requirements and
restrictions on samples and researchers, and the identification results
are greatly affected by subjective and objective
factors(Carvalho, Neto, Brasil, &
Oliveira, 2011 ; P. D. Hebert,
Cywinska, et al., 2003 ; Shen et
al., 2016 ). In recent years, DNA barcode technology has developed
rapidly and has gradually become one of the main methods for biological
identification. With the implementation of the Barcoding of Life
project, DNA barcodes have been widely recognized as a basic tool for
species identification, mitochondrial gene cytochrome C oxidase I
(COI ) serves as the core of the global animal biometric system
could effectively distinguish Crustacea
(Costa et al., 2007 ;P. D. Hebert, Cywinska, et al.,
2003 ; P. D. Hebert, Ratnasingham,
& deWaard, 2003 ). However, the successful application of DNA barcodes
is also affected by many factors, as an important part of DNA barcode
technology, the establishment of a standard life barcode library is of
great significance. In the era of high-throughput sequencing, there is
high probability of tentative, incorrect, or low-quality sequences being
submitted to databases (L. L. Wong
et al., 2011 ). Therefore, compared with the commonly used barcode
databases GenBank (NCBI), DDBJ, EMBL, etc., the BOLD database, which
conducts strict review and screening of submitted data, is relatively
more accurate and applicable(Macher,
Macher, & Leese, 2017 ; Z. Wang et
al., 2009 ). In addition, as the fundamental units in biological
research, species can be defined on the basis of various operational
criteria. At the same time, with the acquisition of a large number of
barcodes, there has been growing use of molecular approaches for species
delimitation (P. D. N. Hebert &
Gregory, 2005 ; Luo, Ling, Ho, &
Zhu, 2018 ). At present, sequence analysis for species delimitation
mainly includes tree based method, distance based method and character
based method, of which the first two have higher universality and
applicability (Birch, Walsh,
Cantrill, Holmes, & Murphy, 2017 ). The combined use of multiple
molecular methods will improve the accuracy of the species definition
results. Therefore, as many different types of molecular methods as
possible should be used for comprehensive species definition.
In fact, both morphological identification and molecular definition are
supporting tool for species identification. The combination of multiple
methods will produce more objective and real species identification
results, the species boundaries will be clearer. The main aim of this
study was to objective and truthful assessment the shrimp diversity at
both taxonomical and molecular level, and provides helpful information
for future conservation and fisheries resource management of the shrimp
in Henan.