Philippine Journal of Science 147 (3): 357-361, September 2018 ISSN 0031 - 7683 Date Received: 15 Jun 2017 New record of Thalassina spinosa (Crustacea: Decapoda: Gebiidea: Thalassinidae) from the Philippines Agatha Maxine B. Bedi1,* and Jurgenne H. Primavera2 1Camp John Hay, Baguio City, Philippines 2Zoological Society of London - Philippines, La Paz, Iloilo City, Philippines The mud lobster Thalassina spinosa Ngoc-Ho and de Saint Laurent, 2009 is reported for the first time in the Philippines based on material collected from a mangrove swamp of Ibajay, Aklan in Panay Island. It is the third species of the genus Thalassina recorded from the country. Although burrowing activities of the Thalassina species create volcano-like mounds that are commonly seen in coastal areas, their species are very little known in the country. Four plots, each measuring 10 m x 10 m, were laid out in the 44-ha Katunggan It Ibajay Eco-Park (KII) which is situated inside a 70-ha mangrove patch with 27 mangrove species in the villages of Naisud and Bugtong-Bato. Juvenile specimens of T. spinosa and T. anomala specimens were obtained from the same plot located in a mixed forest along the banks of the main tidal creek. The mud lobsters’ mounds ranged from 2 cm to 30 cm in height and 4 cm to 15 cm in width. All T. spinosa specimens showed a spinose carapace and an armed cervical groove. Diagnostic characters and geographical distribution of T. spinosa are briefly discussed. Key words: distribution, Gebiidea, Indo-West Pacific, Panay Island, Philippines, Thalassina INTRODUCTION but their large mounds can be easily recognized. The mounds are often associated with mangrove swamps or Among decapod crustaceans, the family Thalassinidae mangrove forests (Sankolli 1963). Ng and Kang (1988) is classified in the infraorder Gebiidea. Thalassina noted that T. anomala seemed to develop a tolerance to Latreille, 1806 is the sole genus belonging to the family the noxious anaerobic mangrove mud. Their constant and commonly called mud lobsters. It contains ten species digging and burrowing activities, however, aerate the from the Indo-West Pacific region (Lin et al. 2016): T. mangrove soil, bring fresh mud to the surface, and thus anomala Herbst, 1804; T. australiensis Sakai and Türkey, play a role in the recycling of nutrients in the mangrove 2012; T. gracilis Dana, 1852; T. kelanang Moh and Chong, ecosystem. 2009; T. krempfi Ngoc-Ho and de Saint Laurent, 2009; T. pratas Lin, Komai & Chan, 2016; T. saetichelis Sakai Only two mud lobster species – T. anomala and T. and Türkey, 2012; T. spinirostris Ngoc-Ho and de Saint squamifera, widely distributed across the Indo-West Laurent, 2009; T. spinosa Ngoc-Ho and de Saint Laurent, Pacific – have been reported from the Philippines 2009 and T. squamifera De Man, 1915. (Ngoc-Ho & de Saint Laurent 2009). During a recent field research in Panay Island, the researchers found Species of Thalassina are shy and inhabit in burrows Thalassina spinosa as a new record and the third species found in littoral and infra-littoral zones (Holthius 1991), of the genus from the Philippines. The present paper provides new information on T. spinosa based on the *Corresponding author: [email protected] collected material. 357 Philippine Journal of Science Bedi & Primavera.: New Record of Thalassina Vol. 147 No. 3, September 2018 spinosa from the Philippines MATERIALS AND METHODS of the animal. Mounds with moist and black mud were partially excavated to place the trap securely in the hole, Study Area in the late afternoon around 17:00 h and retrieved the Thalassina specimens examined in this study were next morning at 08:00 h. However, individuals were collected from Katunggan It Ibajay Eco-Park (KII), Ibajay, also caught by directly picking from the entrance of Panay Island in 2016. KII is situated in a 70-ha mangrove their mounds when the water level rose due to high tide patch that has high plant species diversity, with mature (at or rainfall. They were then washed, and the total length least a century-old) and young (less than a century-old) (from the tip of the rostrum to the tip of the telson) and mangrove trees. Natural mangroves cover 50 ha and the carapace width were measured with a vernier caliper. remaining area comprises plantations of Nypa fruticans, Specimens were labelled and stored in 70% ethanol for settlements and cleared areas (Lebata et al. 2012). preservation. The morphological features used in the description follow the terminology used in Ngoc-Ho The total area has three creeks (Fig.1); the main creek and de Saint Laurent (2009). forms Naisud River towards the sea and turns into a creek as it moves landward. Two other creeks are Paraw Architectural (width and height of mounds), creek and a shorter creek that ends in a mature forest of physicochemical (salinity and pH), and environmental Avicennia rumphiana and Avicennia officinalis. parameters (fauna and flora) were measured and identified in the plots. A tape was used to measure the mound Four sampling plots were designated in KII (Fig.1): dimensions. A pH meter and a refractometer were used plot A (Ceriops decandra patch), plot B (mixed species to measure pH and salinity of the water, respectively, community), plot C (mature forest of A. rumphiana and inside the mounds. A. officinalis), and plot D (Nypa plantation). Sampling plots of 10 m x 10 m were measured with a transect tape, demarcated with sticks and tied with yellow ribbons for visibility. RESULTS Juvenile individuals of T. spinosa and T. anomala were Method collected by hand-picks and some of them excavated For capturing mud lobsters, two bamboo snare traps used from their mounds during high tide or rainfall in plot B. by fishermen to capture crabs were inserted into their Adult T. anomala individuals were caught during 12 snare burrows. The cylindrical trap (31 cm long by 3.7 cm in trap trials. The 67% snare failure rate was mainly due to diameter) contained two holes: one for the trigger and the ability of the mud lobster to sidestep the trap (Fig. 2) the other for a paddle-like piece of wood to slip in and by making a new exit hole or exiting from one of tunnels. block the trap entrance if triggered by the movement Figure 1. A biotope map of KII indicating the position of the creeks and sampling plots. Retrieved and modified from “Baseline assessment of fisheries for three species of mud crabs (Scylla spp.) in the mangroves of Ibajay, Aklan, Philippines” (Lebata et al. 2007). 358 Philippine Journal of Science Bedi & Primavera.: New Record of Thalassina Vol. 147 No. 3, September 2018 spinosa from the Philippines Table 1. Mud lobster samples collected from each plot. Thalassina spinosa Ngoc-Ho and de Saint Laurent, 2009 Material examined. PHILIPPINES, PANAY ISLAND, Plots Number of individuals AKLAN PROVINCE, Ibajay, Katunggan It Ibajay Eco- A 2 T. anomala Park, mangrove swamp, 11°45’6.7"N, 122°11’9.4"E, 4 T. spinosa B Collector: A.M. Bedi, Jun 2016, four females. 4 T. anomala C 2 T. anomala The total length (TL) and carapace width (CW) of the four female specimens are as follows: 1st specimen: 101.6 mm D 0 TL, 15 mm CW; 2nd: 101.6 mm TL, 12 mm CW; 3rd: 76.2 mm TL, 12 mm CW; and 4th: 100 mm TL, 15 mm CW. Two mature Avicennia rumphiana and Avicennia alba The specimens were initially deposited in several areas. trees bordered plot B. Small mounds were dominant, However, only one specimen (76.2 mm TL, 12 mm CW) ranging from 2 cm to 30 cm in height and 4 cm to 15 cm has been maintained by the science club of Bugtong-Bato in widest diameter. The mounds of T. spinosa individuals high school. were constructed from clayish and sandy soils. Each Description. The rostrum has an obtuse tip and a lateral primary mound contained one straight tunnel, measuring border with seven to ten round tubercles. The carapace less than one meter and leading into the ground. Mounds including the dorsal and branchial regions bears numerous were separated from each other and significantly smaller spines and a long posteromedian process (Fig. 3A and in size compared to bigger mounds found in other plots, 3C). The cervical groove is armed with eight to ten particularly in plot C where adult T. anomala individuals large median spines posteriorly and three lateral spines. were collected. Plot C was located at the edges of creek The abdominal pleura are rounded and bordered by 3,400 m into the mature forest of A. rumphiana/A. prominent tubercles; the abdominal sternites have two officinalis. The mounds ranged from 1 m to 2 m in height to five median tubercles. The pereopods are armed with and diameter. The mounds were stacked vertically or numerous spines. The pereopods 1 are unequal or subequal horizontally on other mounds and formed island-like in size; the merus has two to five large proximal spines; connections or ‘condominiums’ that ranged from 6 m to the propodus is armed with conspicuous round tubercles 24 m in diameter. on the dorsal and median carinas of the lateral surface, extending in full length, the lateral ventral carina bears round and elongated tubercles. The pereopod 2 ischium is armed with four or five ventral spines; the merus is armed with six to nine dorsal spines; the carpus has two or three dorsal spines; the propodus is unarmed, without or with small discontinuous tufts of setae near the dorsal border of the mesial surface, a discontinuous curved row of setae is found near the ventral border and at the base of the fixed finger, respectively.