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Ganl. Bull. Singapore 70 (Suppl. 1) 2018 
group include morphological characteristics that describe each taxonomic level (up to 
order) and feeding habits. Biological notes are made with reference to Yule & Yong 
(2004), Tang et al. (2010), Tan et al. (2010), and Tran et al. (2015). 
For each taxon, the distribution of the group is supplemented with family-level 
information. A checklist indicating the presence of families (or lowest practicable 
level of identification) at each site is also presented. This checklist is derived from 
all samples collected during the period between October 2013 and January 2015 
(encompassing both the spatially extensive survey and higher frequency surveys of 
three sites). Organisms from this study of the aquatic fauna were provided to a parallel 
team working on genomics and imaging, for a depository of photographic images and 
of barcodes (Kutty et al., 2018). 
Results 
In total, 82 taxonomic groups (76 families and six higher taxa) of aquatic 
macroinvertebrates were found during the study throughout the Nee Soon freshwater 
swamp forest, with the majority of these families from the phylum Arthropoda (Table 
1). The most diverse class of organisms recorded within Arthropoda was Insecta (66 
families in total). Other arthropod classes recorded were Malacostraca (two families 
and one infraorder), Arachnida (two families) and Entognatha (one family). The 
phylum Mollusca was represented by two classes, namely Gastropoda (four families) 
and Bivalvia (two families). Finally, the phylum Annelida was represented by two 
classes, which were Clitellata (two families) and Oligochaeta (one family). 
The macroinvertebrate classes in the freshwater swamp forest appear to 
have differing distributions, with both classes of Mollusca only being found in 
the northeastern section of the Nee Soon drainage, as well as the class Ostracoda 
(Table 2). The class Clitellata is found only at one site, with leeches from the family 
Erpobdellidae (order Arhyncobdellida) being recorded at site 11 and leeches from 
the family Glossiphoniidae (order Rhynchobdellida) being recorded at site 32. Other 
aquatic macroinvertebrate groups are more evenly distributed throughout the Nee 
Soon freshwater swamp forest, with Insecta, Malacostraca, and Arachnida being the 
most common. Entognatha and Oligochaeta are somewhat less common, but are also 
found throughout the Nee Soon drainage. 
Class INSECTA 
The insects are the most diverse macroinvertebrate group found throughout the Nee 
Soon drainage, with a total of nine orders and 66 families recorded. Most insects 
found in the streams of the Nee Soon drainage are in their larval stage, with the adult 
stage being terrestrial rather than aquatic. Many of the classes recorded in the Nee 
Soon drainage such as the stoneflies (Plecoptera) and the mayflies (Ephemeroptera) 
