Species Diversity and Abundance of Freshwater Crab of the Genus Allacanthos in Buner District of Khyber Pakhtunkhwa Pakistan

| The crab found in fresh water is a source for proteins having immense importance and its use as a food is not hidden from anyone. Its use by the traditional healers and animal therapists as a healthy calcium supplement and in healing of other injuries is also proven. In the present study, the diversity and abundance of crabs from Buner district of Khyber Pakhtunkhwa Pakistan were looked over, over a period of three years extending from June 2013 till June 2016, collected at different sampling points. Extensive surveys were conducted for three years at different timings during the active periods of crab life. To have a comprehensive study of the crab fauna of Buner District, nine different localities were selected for conduction of survey. The results showed that there were two crab species yawi and Smalley. These species belong to Allacanthos. They have gonopod with a distal portion of mesio laterally flattened. They have a cephalic sub distal portion which is concave. There is a narrow marginal process with an almost straight distal end and a sharp tip lateral part with an apex. Periodic and corporal aspects inclined the abundance of Allacanthos. The dominant species was Allacanthos yawi (62.9%). The abundance was variable according to habitat type. Allacanthos yawi had abundance in Pir Baba and Budal localities. The season was also a factor for variation in their diversity. They were mostly found the June, July month. There is a regular decline in the diversity of these species so research on crabs are necessary and an improved understanding of localities are necessary to prevent biodiversity degradation and loss in this area. Novelty Statement | There is no work found on Allacantous crab of Buner. No such study was carried out by any Zoologist in Buner District. The understanding of localities is necessary to prevent biodiversity degradation and loss in this area. So hope this study will help to prevent endangerednes of species. Article History Received: July 26, 2018 Revised: January 08, 2020 Accepted: February 05, 2020 Published: April 30, 2020 Authors’ Contributions WAS designed the experiments and wrote the article. GR presented the idea of the study. KK analysed the data. IA provided reagents/materials/analysis tools. SB studied the area. SI collected the crabs. DS and SGA did the field survey.


Introduction
T he study of invertebrates as an origin of medicine has always been considered interesting and fruitful field in research. Various medicinal firms have succeeded crab. This is because they have bioactive chemicals in them (Albuquerque et al., 2012). Certain organism's cone shells and mussels may be harvested in a number for they are used in neuro-medicines. A freshwater snail is used in the treatment of bones and joint disorders as the local therapy in china and India (Antony et al., 2011).
Crabs, besides an essential part of the environmental system, are used as food in various countries. As the fact is, the marine type is mostly used as a food but in some countries, the crab from fresh water is also found edible. Its importance as a food is also known to people of countries like China, Indonesia, France, Japan, Spain, Philippines and the United States (Gülle, 2005).
Diversity of marine and fresh water crab discussed by different authors as crabs are economically important for different countries and another reason is regular decline in their diversity and species composition (Wehrtmann et al., 2016). Different factors responsible for their decline like overharvesting, environmental crises, destruction and degradation. This is where concerns arise about the fact that less studies are there about the diversity and environment of crabs, that might help in their protection and conservation.
According to Brandis et al., 2000, crabs are studied on a number of basis like biological, ecological and population features in all over the world (Brandis et al., 2000), however very less studies on the species in Buner are conducted. This study was purposed at demonstration of Species Diversity and Abundance of freshwater crab of the genus Allacanthos in Buner district of Khyber Puktun Khawa, Pakistan.

Methods and Materials
Area of study Collection of sample Extensive surveys were conducted for three years at different timings during the active periods of crab life. To have a comprehensive study of the crab fauna of Buner District, following localities of the area Table 1 were selected for conduction of survey.
Crabs were collected in the selected areas during three years period from June 2013 till June 2016 during the active period of crab map 1. Fortnight visits were planned and conducted. 2000 traps (Fyke-net), set at each point of collection were used to catch the Allacanthos specimens. Before storage of the collected specimens in the museum of Zoology department Abdul Wali Khan University Mardan, they were killed in a bottle containing anesthesia.

Data analysis
One-way ANOVA was used for comparison of the numbers of crabs amongst localities and seasons.
The Pearson correlations were used to test the interrelationships between the numbers of crabs and their bodily features.

Diagnosis, description, color, distribution and ecology of allacanthos yawi
They had a curved head part, and a straight distal part. The spine was in the apical portion while gonopod was placed distally and was narrow. The lateral part was smooth. They were small sized about less the 30cm. Elaborated in middle. Dorsal surface was mostly flat. Gastric pits were paired and smooth. The cervical groove was narrow and shallow. The postfrontal portion was very distinct with shallow between them.in the dorsal portion front margins were straight. The upper orbital portion was not crinite. A lower orbital portion had fainted papillae. The Claws was rounded with fleshy tufts, typically no spots. They had pereiopods with fine sparse hairs. First pereiopods completely closed. They were different. Mostly right was larger than left. Palm was swollen. Finger gripping when closed. They had triangular teeth. All the abdominal portion was free.

Figure 2: Allacanthos crab Museum Specimen.
Carapace and pereiopods were Olivia colored. Some areas were the lighter green. The specimens (Figure 2) were collected in streams of different heights and slopes and consisting of different ranges of volume of water. A rich vegetation cover provided shade for the study area. Various sizes stone pebbles, clay and sand were the main components of the waterbed. The half-decomposed leaves made the spot favorite for Allacanthos yawi aided by other organic substances.
They were caught all year long in the freshwater streams of Buner district, consisting of a range of volume of water.

Discussions
This is the first-ever study on Crab diversity in district Buner of Khyber Pakhtunkhwa Pakistan. This study result show that we had found the diversity of only one genus Allacanthos. They had only two species yawi and smalley diverse in the study area. Such type of study has been reported by Magalhães, et al. (2010). He found different species of Allcantos from Central America in same ecological condition as found in Buner district. They were compared with University of Washington crab guide and found that it has the same size, colour, distribution and body structure.
This study is also a comparison to previous studies in Thailand. But the Thailand has 746 species of sea-borne crabs (Ng and Davie, 2002). 54 species of sea-borne crabs were found in coastal areas of Cape Panwa, Phuket Province (Wisespongpand et al., 2009), Mu Ko Angthong Marine National Park, Surat Thani Province, had 54 species (Wisespongpand et al., 2008), and Mu Ko Surin National Park, Thailand had 77 species (Wisespongpand et al., 2007). Moreover, 11 families, 37 genera and 72 species of marine crabs from a small trawl fisherywere reported by Khoyngam and Lauhachinda (1985).
As reported by Magalhães, et al. (2010) from southern Costa Rica, Central America that Allacanthos species mostly found in freshwater and sloppy and humid area. The same was found there. Most streams and freshwater springs were found with mud, humid and in between trees and agricultural land. Some marine crabs distributed in high temperature, transparent depth and saline water (Manmai et al., 2013).
The seasonal abundances of Allacanthos smalley and Allacanthos yawi were same to other freshwater crabs like the genus Mediapotamon (Wang et al., 2019). They were mostly found in the month of June to October and then from March to May in Buner. As these seasons has humidity and other constituents responsible for the growth of them.
As habitat has an important function for fresh water crabs. So, management of these species should be taken into account specially the habitats in which it is found abundance (Magalhães, et al., 2010). As reported that they are freshwater so they are found in that localities which has freshwater streams in between their mountains. Pirbaba and Budal were favorable for Allacanthos yawi. Allacanthos smalley was found mostly in localities of Gokand, Nagrai, Totalay and Malka area.
During our study in this area we come to know that most of the practitioners and Hakeem use this for medicinal purpose, so a clear and intense care is required on these species to prevent them from becoming threaten.

Conclusion
We conclude our study with this remarks that we had only two species Allacanthos yawi and Allacanthos smalley in district Buner of Khyber Pakhtunkhwa Pakistan. There is a regular decline in the variety and quantity of these species due to Zoo therapeutic uses and other pollution, so research on crabs and an improved understanding of habitat are necessary to prevent loss of biodiversity.