sd-sample article P.N.Y. Young and I.K.C. Fontanilla 53 SCIENCE DILIMAN (JANUARY-JUNE 2014) 26:1 53-76 Biodistribution of the Informal Group Basommatophora in the Philippines Patrick Noel Y. Young* Ian Kendrich C. Fontanilla University of the Philippines Diliman _______________ *Corresponding Author ISSN 0115-7809 Print / ISSN 2012-0818 Online ABSTRACT B a s o m m a t o p h o r a i s a n i n f o r m a l g r o u p w i t h i n t h e m o l l u s c a n s u b c l a s s P u l m o n a t a c o m p r i s i n g o f a i r - b r e a t h i n g f r e s h w a t e r s n a i l s t h a t a r e t y p i c a l l y c h a r a c t e r i z e d b y e y e s p o t s l o c a t e d a t t h e b a s e o f t w o n o n - contractile tentacles and two external genital orif ices. They also have varied shell structures and habitats, not only within the group but also within families. Families of the Basommatophora are highly ubiquitous and may play a role in the life cycles of various parasites of humans and animals. Basommatophora has a worldwide geographical distribution across freshwater, terrestrial and marine habitats. However, little is known on their distribution in the Philippines. This report focuses on describing t h e b i o g e o g r a p h i c a l d i s t r i b u t i o n o f t h e b a s o m m a t o p h o r a n s i n t h e P h i l i p p i n e s t h r o u g h d a t a g a t h e r e d f r o m m u s e u m c o l l e c t i o n s , f o r e i g n d a t a b a s e s a c c e s s e d o n l i n e , a n d i d e n t i f i c a t i o n o f s p e c i e s f o u n d i n various literatures. A qualitative description of the distribution of each Basommatophora family in the Philippines is given by distribution maps, indicating locations where specimens were collected and/or identif ied. A t o t a l o f 3 3 6 c o u n t s o f b a s o m m a t o p h o r a n s f r o m 2 2 g e n e r a w e r e encountered from available literature, museums and public databases. The majority of the occurrences are from the genera Siphonaria. The data and maps generated describe most of the distribution to be in Luzon, with Visayas and Mindanao having close counts with each other. The Philippines has the third most occurrences and genera of basommatophorans of all tropical countries in the world. However, the true diversity of the group c o u l d b e h i g h e r i f a m o r e s y s t e m a t i c s a m p l i n g o f t h e a r c h i p e l a g o i s conducted. Keywords: Basommatophora, Philippines, biogeographical distribution Biodistribution of the Informal Group Basommatophora 54 INTRODUCTION Basommatophora is currently regarded as an informal group of the molluscan subclass Pulmonata, containing about 2500 species that are grouped into the superfamilies Amphiboloidea and Siphonarioidea as well as the clade Hygrophila. There are nine recognized families under this group (Bouchet and Rocroi 2005). However, it was found recently that Basommatophora is polyphyletic, and all its members were moved into a new taxon, Panpulmonata (Jörger and others 2010). The most distinct observable characteristics of this group are the eyespots, which are normally located at the base of two non-contractile tentacles, and the two external genital orif ices. Other features seem to be shared with other pulmonate superorders, though specializations may occur if there are major changes in habitat or body form (Solem 2008). Basommatophora has a worldwide geographical distribution, with species inhabiting predominantly freshwater but may also thrive in marine and terrestrial habitats (Fretter and Peake 1978). Like other invertebrates, freshwater gastropods present an overall pattern of high diversity in the tropics, with low levels of species richness and endemicity at higher latitudes. Small oceanic islands are noteworthy for generally low levels of freshwater gastropod species richness and endemism (Starmühlner 1979). Most species are capable of self-fertilization, so it is possible to populate a new body of water; however, cross-fertilization is the normal mode of reproduction (Solem 2008). Egg-laying is the norm for the basommatophorans, although two species of Protancylus have been observed to brood eggs (Albrecht and Glaubrecht 2006). Generation time is usually short, so enormous numbers of snails can build up very quickly during favorable conditions. As a result, basommatophoran snails show minor variation among populations (Solem 2008). Families in this suborder inhabit a great variety of freshwater habitats, living in water of less than 12 ft depth. Only rarely have there been live species observed at relatively great depths. These species must depend upon cutaneous respiration or air bubbles for oxygen exchange while species living in shallow waters come to the surface at regular intervals to breathe. In addition, variations in shell structure and form exist (Solem 2008). The forms of the shell vary widely not only within Basommatophora but also within the individual families. Family Siphonariidae has shells that are cap-shaped, with an irregular bulge on the right side and a secondary gill in the mantle cavity. Amphibolidae has high-spired and dextral shells and are also unique in having operculum as adults. Gills are lacking but amphibolids possess an osphradium (olfactory organ) in the mantle cavity. A high-spired dextral shell also commonly characterizes the families Chilinidae and most of Lymnaeidae. P.N.Y. Young and I.K.C. Fontanilla 55 Planorbidae often has a planispiral shell that coils sinistrally, with their spire reduced and all whorls being arranged into a single plane. A sinistral shell is also always present in Physidae. Reduction in the elevation of the spire and the number of whorls also vary. Partial reduction of the whorls has occurred in Latiidae. A vestigial spire is also present in some species of Planorbidae (Fretter and Peake 1978, Pechenik 2005). Because of these and other variations, it is diff icult to f ind structures that are common to all taxa that can def ine the group (Solem 2008). Families of Basommatophora are usually highly visible and are ecologically signif icant both for serving as a food resource for vertebrates and for browsing on the shallow-water encrusting organisms such as algae, fungi, and protozoa. Certain snails of this order are also of medical signif icance by serving as intermediate hosts for trematode parasites of both humans and domestic animals. Some planorbids transmit schistosomiasis in Africa, the West Indies, and South America while lymnaeids are involved usually in both sheep and cattle liver fluke life cycles (Solem 2008). Previous data identif ied f ive basommatophoran families present in the Philippines, namely Acroloxidae, Lymnaeidae, Physidae, Planorbidae, and Siphonariidae (Pagulayan 1995, Springsteen and Leobrera 1986). Ancylidae, formerly a distinct family within Basommatophora, was placed under Siphonariidae (Bouchet and Rocroi 2005). However, there is no consolidated data on the biogeographical distribution of the group in the Philippines. This study, therefore, aims to survey available literature and journals, museums and online databases in order to address this problem. MATERIALS AND METHODS Data for the distribution of basommatophorans in the Philippines were gathered from various databases, using known basommatophoran families in the modern taxonomy scheme provided by Bouchet and Rocroi (2005). The online network of Global Biodiversity Information Facility (http://data.gbif.org/ welcome.htm), which compiled various datasets around the world, was accessed through the internet. A spreadsheet of basommatophoran occurrences was downloaded (http://data.gbif.org/occurrences/downloadSpreadsheet.htm?c[0].s=20 &c[0].p=0&c[0].o=1491) and formatted to show the country and location where the species were collected and which database they were obtained from. A listing of basommatophoran occurrences in the Philippines found in relevant literature was also included. Basommatophoran occurrences in the Philippines found in both listings are tabulated in Table 1. Biodistribution of the Informal Group Basommatophora 56 Family Acroloxidae Acroloxus sp. Tapul Group, Lapac Island, Vicinity of Siasi, USNM Sulu Archipelago (1) Family Lymnaeidae Amphipeplea sp. Marinduque (1) MCZ Amphipeplea cumingiana Camarines Sur (1), * (1) UCM Amphipeplea luzonica Zamboanga (1) UCM Amphipeplea quadrasi Donsul, Sorsogon (1); Ermita, Manila (1); ANSP Manila, Manila (1) Bullastra cumingiana Solano (1) NBCNL Bullastra velutinoides * (1) ZMB/Moll Lymnaea sp. Abra de Ilog, QCC, Mindoro (1); Cebu (1); USNM Laguna de Bay, Luzon (1); Mabilangan, Mt. Data, Mt. Province, Luzon (1); Panay Island, Jaro River (1); Tapul Group, Lapac Island, Vicinity of Siasi, Sulu Archipelago (6) Sulu Islands (1) ANSP Lymnaea blaisei * (1) UCM Lymnaea cumingiana Bayninan, Banaue, Ifugao (1); Sinebaran Creek, NMP Matnog, Sorsogon (1) Lymnaea monticola * (1) MNCN Lymnaea pereger Trinidad Mountain, Benguet (1) ANSP Lymnaea rubiginosa Cebu (1) NMP Lymnaea swinhoei Manila (1); Trinidad Valley (1) MCZ Trinidad Valley (1) NMP Myxas sp. Calamianes (1) MNCN Myxas cumingiana (=Myxas * (1) FLMNH cumingianus and * (3) LMD M. cumungi) Catanduanes (1) MNCN * (1); Bukid River, Tacloban, Palo, Leyte (1); NMP Candaba Swamps, Candaba, Pampanga (1); Dagami, Guinarona, Leyte (1); Macalajar (1); Table 1. Basommatophoran genera and species found occurring in the Phil ippines. No d istribution data are ind icated for species marked with (*) because of no specificity in location. Sources for each specimen are the following: USNM (NMNH Invertebrate Zoology Collections), MCZ (Museum of Comparative Zoology, Harvard University), UCM (CUMNH Mollusc Collection), ANSP (MALACOLOGY), NBCNL (Naturalis Biodiversity Center (NL) – Mollusca), ZMB/Moll (SysTax – Zoological Collections), MNCN (Museo Nacional de Ciencias Naturales, Colección de Malacología), FLMNH (Invertebratezoology), NBCNL (Naturalis Biodiversity Center (NL) – Mollusca), TOYA (Mollusca Specimens of Toyama Science Museum), NMR (Natural History Museum Rotterdam (NL) – Mollusca Collection), NMP (National Museum of the Philippines), Springsteen and Leobrera’s Shells of the Philippines (SP), Pagulayan’s Studies on the biodiversity of the molluscan fauna of Lake Taal, Batangas (P), Boragay’s A survey of gastropods at the University of the Philippines Diliman Campus (B), and Bequaert and Clench’s Philippine Lymnaeidae and Planorbidae (PLP). Ind ividual (Species) Location (Count) Dataset P.N.Y. Young and I.K.C. Fontanilla 57 Table 1. Basommatophoran genera and species found occurring in the Phil ippines. No d istribution data are ind icated for species marked with (*) because of no specificity in location (cont’n.). Ind ividual (Species) Location (Count) Dataset Negros Occidental (1) MCZ Musuan, Bukidnon, Mindanao (1) B * (1) NBCNL Myxas imperialis Batangas, Lipa (1); Cebu (1); Nagcarlang, Palayan, MCZ Laguna (1); San Juan River, Calamba, Laguna (1); Manila (1) Myxas luzonica * (1) MNCN Myxas quadrasi * (4) FLMNH Porac (1) MNCN Radix sp. Tapul Group, Lapac Island, Vicinity of Siasi, Sulu USNM Archipelago (1) Radix auricularia (=Lymnaea Batang Creek, San Victor, Tacloban, Leyte (1); NMP auricularia) Bukid River, Tacloban, Palo, Leyte (1); Quilot River, Palo, Leyte (1); Tacloban, Leyte (1); Tributary of Bukid River, Tacloban, Leyte (2); Tributary of Quilot River, Guingawan, Tacloban, Leyte (2); Lake Taal (1); Daral-og River, Tacloban, Leyte (1) PLP Radix philippinensis Bohol, Vilar Id. , Barrio Toog (1); Calbiga, MCZ (=Lymnaea philippnensis Samar (1); Cebu (1); Binan, Laguna (1); and Lymnaea philippinica) Mahaihai, Laguna (1); Albuero, Leyte (2); Caridad, Leyte (1); Ormoc, Leyte (1); Palo, Leyte (2); Tarragona, Leyte (1); Manila (2) Cagbatan Island, Coron, Palawan (1); NMP Carmen-Sagbayan-Bacani Road (1) Cebu (1); Mangaldan (1) PLP Cebu (1); Guihulngan (1); Manila (1) MNCN Bilar, Bohol Island (1) UCM Maynit, Laguna (1); Manila (1) ANSP * (4) FLMNH Radix quadrasi (=Lymnaea * (1) FLMNH quadrasi and Bulinus UP Diliman (1) NMP quadrasi) Agus River, Manila (1) UCM Mindanao, Macajalar (1) MCZ Radix swinhoei Macajalar (1) MCZ Stagnicola wyomingensis Tapul Group, Lapac Island, Vicinity of Siasi, USNM Sulu Archipelago (1) Family Physidae Limnophysa sp. Tapul Group, Lapac Island, Vicinity of Siasi, ANSP Sulu Archipelago (3) Tapul Group, Lapac Island, Vicinity of Siasi, MCZ Sulu Archipelago (2) Tapul Group, Lapac Island, Vicinity of Siasi, MNCN Sulu Archipelago (3) Tapul Group, Lapac Island, Vicinity of Siasi, ZMB/Moll Sulu Archipelago (1) Biodistribution of the Informal Group Basommatophora 58 Physa sp. * (1) ANSP * (2); Panay Island USNM Tapul Group, Lapac Island, Vicinity of Siasi, PLP Sulu Archipelago (1) Tapul Group, Lapac Island, Vicinity of Siasi, ZMB/Moll Sulu Archipelago (2) Physa heterostropha Tapul Group, Lapac Island, Vicinity of Siasi, ZMB/Moll Sulu Archipelago (1) Physa hungerfordiana Aparri, Cagayan (2); Claveria, Cagayan (1); USNM Malabon, Manila (2); Porac (1) Claveria, Cagayan (1); Morong (1) LMD Manila (1) MCZ Manila (1) MNCN Physa philippina * (3) USNM Bosoboso near Manila (1) ANSP Physa semperi * (1) USNM Family Planorbidae Amerianna quadrasi Lake Mainit (1) MNCN Amerianna sulcifera * (1) FLMNH Anisus convexiusculus Ilocos Sur, Rio del Pueblo de Sinay (1); MCZ San Juan del Monte (1); Surigao (1) Anisus corinna Leyte, Baybay (2) MCZ Anisus quadrasi Leyte, Palo (1); Mindoro (1); San Juan River, MCZ Manila (1) Bulinus sp. Sulu Archipelagi, Tapul Group, Lapac Island, USNM Vicinity of Siasi (1) Bulinus boholensis Bohol, Baclayon (3) MCZ Bulinus bullulus Mindoro (1) MCZ Bulinus camelopardalis * (1) MCZ Bulinus hungerfordianus * (1); FCMNH (B. hungerfordiana) Dagami, Digabonegan, Leyte (1); Palo, Leyte (2); MCZ Tarragona, Leyte (1); Tolosa, Leyte (1); Manila (1); Irrigation Canal, Bo. Dita, Cabuyao, Laguna (2); Laguna Bay, Laguna (1); Alabang River, Manila (1); Muntinglupa River, Manila (1); Virac, Catanduanes (1) Bulinus luzonicus * (1) MCZ Bulinus mindoroensis Mindoro (1) MCZ Bulinus ustulatus Mindoro (1) MCZ Cyclophinus canaliferous Mindoro (1) MCZ Gyraulus chinensis * (2) SMF Lake Taal (1) P UP Diliman (1) B Gyraulus compressus * (1) FLMNH Gyraulus convexiusculus * (2) FLMNH Aparri, Cagayan (1); Boac (1); Pasig River, MNCN Manila (1); Visita Palanas, Lacy (1) Table 1. Basommatophoran genera and species found occurring in the Phil ippines. No d istribution data are ind icated for species marked with (*) because of no specificity in location (cont’n.). Ind ividual (Species) Location (Count) Dataset P.N.Y. Young and I.K.C. Fontanilla 59 Gyraulus prashadi Zambales Prov., San Antonio (2) MCZ Gyraulus quadrasi * (1) FLMNH Hippeutis umbilicalis Palo, Leyte (1) MCZ mearnsii Indoplanorbis exustus UP Diliman (1) B Pettancylus manillensis Lake Taal (1) P Physastra hungerfordiana * (5) FLMNH Lake Taal (1) P UP Diliman (1) B Physastra quadrasi Lake Mainit (1) PLP Planorbis sp. * (1); Surigao (1); Bohol (1) MCZ * (1) MNCN Sulu Archipelagi, Tapul Group, Lapac Island, USNM Vicinity of Siasi (3) Planorbis compressus * (1) UCM Alrededores, Manila (1); Baclayon, Bohol (1); MCZ Isabela, Luzon (1); Lacy, Siquijor (1); Paco, Manila (1) Ermita, Manila (1); Isabela, Luzon (1); ANSP Loey, Siquijor (1); Manila (1); Marinduque (1) Planorbis corneus * (1); Zamboanga (1) MNCN Planorbis lugubris Batangas, Lipa (1) MCZ Planorbis mindanensis Cotobato, Rio Grande Valley, Lake Baluan (1) MCZ Cotobato, Rio Grande Valley, Lake Baluan (1) USNM Planorbis philippinarum * (1) MNCN Planorbis planorbis * (1) FLMNH Planorbis quadrasi Inopacan (1) MNCN Montalban (1) MCZ Planorbis umbilicalis Cagayan, Buguey (1) MNCN Segmentina umbilicalis Cagayan, Buguey (1); San Antonio, Zambales (1) MCZ Family Siphonariidae Siphonaria sp. Mambajao, Camiguin Island (1) NMP Ambulony Island (1) CAS Maubu Beach, Jojo Island, Sulu Archipelago (1) ANSP Muso, Siasi Island, Sulu Archipelago (1) Turnina Island (2) YPM Cabra Island, Mindoro (1); Cuyo, Palawan (2); Bacuit, Palawan (1) MCZ Siphonaria acuta Palawan, Bacuit (1) MCZ * (1) FLMNH Siphonaria atra Balite Beach, Puerto Galera, Mindoro (1); NMP Bohol (1); Buenavista, Marinduque (1); Cabcaban, Bataan (1), Cagayan de Sulu (1); Ibabang Pulo, Pagbilao, Grande Island, Pagbilao, Quezon (1); Manlumod, Mogpog, Marinduque (1); Puntod, Gaspar Island, Tres Reyes Islands, Marinduque (1); Tawi-tawi Island, Sulu (1) Table 1. Basommatophoran genera and species found occurring in the Phil ippines. No d istribution data are ind icated for species marked with (*) because of no specificity in location (cont’n.). Ind ividual (Species) Location (Count) Dataset Biodistribution of the Informal Group Basommatophora 60 Butas, Mariveles Point, Bataan (1); Cabra Island, MCZ Mindoro (1); Candelaria, Zambales (1); Bacuit, Palawan (1); Cuyo, Palawan (1) Little Santa Cruz, Mindoro (1); * (1) UCM * (3) FLMNH Siphonaria cornuta Balabac, Mangsee del Sur (1); Palawan (1) MCZ Siphonaria corrugata Semirara Island (1) NMP Siphonaria diemenensis Candelaria, Zambales, Luzon (1) MCZ Siphonaria japonica * (2) FLMNH Siphonaria javanica Barangay Tawog, Bulusan, Sorsogon (1); NMP Batangas Bay, Batangas (1); Bulalasas Bay, Or. Mindoro (1); Cata-an River, San Joaquin, Iloilo (1); Malitpalit Islet, Pandan, Catanduanes (1); Morongborongan Island, Sorsogon (1); Muelle Bay, Puerto Galera, Or. Mindoro (1); Pandan, Catanduanes (1); Sinugbuan, San Joaquin, Iloilo (1); Sulangan, Guiuan, Eastern Samar (1); Tabugoe, Pandan, Catanduanes (1) Zamboanga (1) MCZ Siphonaria kurrachiensis Palawan, Bacuit (1) MCZ Siphonaria laciniosa Batangas Bay, Batangas (1); Punta Canomay, NMP Calveria, Burias Island, Masbate (1); Subic, Calimtaan Island, Sorsogon (1) Butas, Mariveles Pt., Bataan, Luzon (1); MCZ Cabra Island, Mindoro (1); Calapan (2); Candelaria, Zambales, Luzon (2); Dapitan Bay (1); Lubang Island, Mindoro (1); Mindoro (1); Santa Margarita, W. Samar (1) * (3) FLMNH * (3) TOYA Siphonaria normalis Balite Beach, Puerto Galera, Mindoro (1); NMP Bobon (1); Bolauos, Narvacan, Ilocos Sur (1); Cabuyo, Torrijos, Marinduque (2); Dapdap, Tagum, Sta. Cruz, Marinduque (2); Honda Bay, Palawan (1); Imelda Park, Ilocos Sur (1); Lusong-Bagac, Bataan (1); Manlumod, Mogpog, Marinduque (1); Melchor Island, Tres Reyes Island, Gasan, Marinduque (1); Parpatong, Bangui, Ilocos Norte (1); Sulvec, Narvacan, Ilocos Sur (1); Suyo, Bangui, Ilocos Norte (1) * (2) FLMNH Siphonaria sipho * (1) UCM Palawan (2) MCZ * (1) LMD Siphonaria siquijorensis Siquijor (1) ANSP Baler, Quezon (1); Lubang Island, Mindoro (1) NMP * (1) NBCNL * (1) NMR Table 1. Basommatophoran genera and species found occurring in the Phil ippines. No d istribution data are ind icated for species marked with (*) because of no specificity in location (cont’n.). Ind ividual (Species) Location (Count) Dataset P.N.Y. Young and I.K.C. Fontanilla 61 Siphonaria sirius Angas Point, Otavi, Bulan, Sorsogon (1); NMP Balbagon Island, Carles, Iloilo (1); Barangay Tawog, Bulusan, Sorsogon (1); Canlubi, Pandan, Catanduanes (1); Cata-an River, San Joaquin, Iloilo (1); Dayhagan, Suchan, Panay Island (1); Catanduanes (1); Macalanhog Island, Gigmoto, Catanduanes (1); Malitpalit Islet, Pandan, Catanduanes (1); Morongborongan Island, Sorsogon (1); Punta Nasio, Taloto-an, Pan de Azucar Island, Concepcion, Iloilo (1); Sinugbuan, San Joaquin, Iloilo (1); Sorsogon (1); Subic, Calimtaan Island, Sorsogon (1) * (1) UCM Table 1. Basommatophoran genera and species found occurring in the Phil ippines. No d istribution data are ind icated for species marked with (*) because of no specificity in location (cont’n.). Ind ividual (Species) Location (Count) Dataset The number of basommatophoran families and genera occurring in tropical countries in the world were also obtained from the online listing and are tabulated in Table 2. Endemicity was also checked by comparing the occurrences between other countries. The website DiscoverLife (http://www.discoverlife.org/) was also used to check for further consistencies. Endemicity was also conf irmed if there were no clear sources refuting it for certain species. Endemic species are tabulated in Table 3. The National Museum of the Philippines in Manila was visited to document and list down the specimens in their collection with the help of Ms. Vivian Ang. The documentation of the specimens are found in Appendix 1. All data were tabulated using a spreadsheet computer program (Microsoft Excel 2007). Locations where each species was found were marked using Adobe Photoshop CS5 on an outline map of the Philippines, from Free US and World Maps.com (http://www.freeusandworldmaps.com). RESULTS AND DISCUSSION A total of 336 recorded occurrences, 21 genera, and 75 species from the listings indicated above were found to occur in the Philippines. These records reveal basommatophorans from f ive families out of nine total based on Bouchet and Rocroi’s (2005) classif ication scheme: Acroloxidae (1 occurrence, 1 genus, 1 species), Lymnaeidae (99 occurrences, 6 genera, 20 species), Physidae (32 occurrences, 2 genera, 6 species), Planorbidae (95 occurrences, 11 genera, 35 species), and Siphonariidae (111 occurrences, 1 genus, 13 species). This is mostly consistent Biodistribution of the Informal Group Basommatophora 62 Table 2. A l ist of tropical countries defined as being in the region between the Tropic of Cancer (23° 26’ 16” N) and Tropic of Capricorn (23° 26’ 16” S) found in the world. Listed also are the number of basommatophoran occurrences and genera that are found occurring in each country. (Accessed through GBIF Data Portal, data.gbif.org, 2014-01-29) Mexico 623 31 Congo 339 19 Philippines 336 21 Cuba 238 20 Indonesia 190 13 Brazil 188 23 India 172 17 Panama 171 17 Jamaica 122 17 Costa Rica 113 16 Uganda 112 11 Guatemala 107 20 Peru 102 17 Venezuela 97 19 Honduras 94 1 Cape Verde 83 5 Thailand 74 13 Haiti 66 13 Kenya 58 12 Nicaragua 54 12 Bolivia 45 7 Sudan 42 8 Dominican Republic 41 11 Oman 40 5 Bermuda 37 7 Ecuador 36 9 Madagascar 35 9 Colombia 35 12 Puerto Rico 35 15 Cayman Islands 33 5 Fiji 33 5 Vietnam 27 6 Liberia 26 5 El Salvador 25 8 New Caledonia 24 7 Sri Lanka 21 6 Suriname 21 7 Senegal 20 4 Tropical Country Number of Occurrences Number of Genera P.N.Y. Young and I.K.C. Fontanilla 63 Papua New Guinea 20 7 Malaysia 16 3 Yemen 16 6 Netherlands Antilles 16 8 Tanzania 15 7 Seychelles 14 2 Cameroon 13 5 Trinidad and Tobago 13 10 Angola 12 3 Singapore 12 8 Sierra Leone 11 4 Malawi 10 3 Vanuatu 10 3 Barbados 10 6 Antigua and Barbuda 9 6 Zambia 8 4 Zimbabwe 6 5 Cocos Islands 5 1 Laos 5 3 Belize 5 5 American Samoa 4 1 Nigeria 4 4 Equatorial Guinea 3 1 Hong Kong 3 1 Ghana 3 2 Namibia 3 2 Gabon 2 1 Gambia 2 1 Dominica 2 2 French Guiana 2 2 Mozambique 2 2 Botswana 1 1 Montserrat 1 1 Niger 1 1 Tropical Country Number of Occurrences Number of Genera Table 2. A list of tropical countries defined as being in the region between the Tropic of Cancer (23° 26’ 16” N) and Tropic of Capricorn (23° 26’ 16” S) found in the world (cont’n.). Listed also are the number of basommatophoran occurrences and genera that are found occurring in each country. (Accessed through GBIF Data Portal, data.gbif.org, 2014-01-29) Biodistribution of the Informal Group Basommatophora 64 Family Lymnaeidae Amphipeplea cumingiana Camarines Sur Amphipeplea luzonica Zamboanga Amphipeplea quadrasi Donsul, Sorsogon; Ermita, Manila; Manila, Manila Bullastra cumingiana Solano Bullastra velutinoides * Myxas cumingiana Catanduanes; Bukid River, Tacloban, Palo, Leyte; Candaba Swamps, Candaba, Pampanga; Dagami, Guinarona, Leyte; Macalajar, Negros Occidental; Musuan, Bukidnon, Mindanao Myxas imperialis Batangas, Lipa; Cebu; Nagcarlan, Palayan, Laguna; San Juan River, Calamba, Laguna; Manila Myxas luzonica * Myxas quadrasi * Radix philippinensis Bohol, Vilar Id., Barrio Toog; Calbiga, Samar; Cebu; Biñan, Laguna; Mahaihai, Laguna; Albuero, Leyte; Caridad, Leyte; Ormoc, Leyte; Palo, Leyte; Tarragona, Leyte; Manila; Cagbatan Island, Coron, Palawan; Carmen-Sagbayan-Bacani Road, Cebu); Mangaldan, Cebu; Guihulngan, Bilar, Bohol Island; Maynit, Laguna; Manila Radix quadrasi UP Diliman; Agus River, Manila; Mindanao, Macajalar Family Physidae Physa hungerfordiana Aparri, Cagayan; Claveria, Cagayan; Malabon, Manila; Porac; Morong, Manila Physa philippina Bosoboso near Manila Physa semperi * Family Planorbidae Anisus corinna Leyte, Baybay Anisus quadrasi Leyte, Palo; Mindoro; San Juan River, Manila Amerianna quadrasi Lake Mainit Amerianna sulcifera * Bulinus boholensis Bohol, Baclayon Bulinus bullulus Mindoro Genus Location Table 3. A list of endemic basommatophoran genera and species found in the Phil ippines with the distribution found in other countries, as can be gleaned from the GBIF spreadsheet, wherein Lymnaeidae, Planorbidae and Siphonariidae were also the most commonly occurring families. Figure 1 presents the families found in the Philippines and their relative numbers to each other. Figure 2 shows the relative numbers of the genera that can be found in the Philippines to each other. P.N.Y. Young and I.K.C. Fontanilla 65 Genus Location Table 3. A list of endemic basommatophoran genera and species found in the Phil ippines (cont’n.). Bulinus camelopardalis * Bulinus hungerfordianus Dagami, Digabonegan, Leyte; Palo, Leyte; Tarragona, Leyte; Tolosa, Leyte; Manila; Irrigation Canal, Bo. Dita, Cabuyao, Laguna; Laguna Bay, Laguna; Alabang River, Manila; Muntinglupa River, Manila; Virac, Catanduanes Bulinus luzonicus * Bulinus mindoroensis Mindoro Cyclophinus canaliferous Mindoro Gyraulus prashadi * Physastra hungerfordiana Lake Taal; UP Diliman Planorbis mindanensis Cotobato, Rio Grande Valley, Lake Baluan Planorbi sphilippinarum * Planorbis quadrasi Inopacan; Montalban Segmentina umbilicalis Cagayan, Buguey; San Antonio, Zambales Family Siphonariidae Siphonaria cornuta Balabac, Mangsee del Sur; Palawan Siphonaria (family Siphonariidae) has the most occurrences in the Philippines, accounting for 33% of the total. The genus has a widespread distribution, with increasing diversity towards the tropics (Vermeij 1973). Hodgson (1999) speculated that the success of the siphonariids in general could be due partly to their resistance to increased temperature and desiccation through physiological, morphological or behavioral adaptations. Furthermore, siphonariids are generalist grazers, feeding on a wide range of microalgae, f ilamentous algae, foliaceous algae, and macro- phytous corticated algae (Underwood and Jemakoff 1981, Jara and Moreno 1984, Santelices and Correa 1985, Godoy and Moreno 1989, Hodgson 1999), as well as lichens (Borland 1950) and cyanobacteria (Chan 2003). Siphonaria can also influence the settlement, growth and survival of algae, as well as barnacle recruitment and survival (Jara and Moreno 1984, Hodgson 1999) because of their occurrence in large numbers. Some species change their vertical distribution according to seasons. It is widely assumed that the vertical distribution of siphonariids is affected by both biotic – e.g. , interspecif ic competition for space (Black 1979, Hodgson 1999) – and wave action (Allanson 1958, Voss 1959, Hodgson 1999). However, more research is needed as little is known about the ecology of tropical species (Hodgson 1 9 9 9 ) . Many basommatophoran snails have a widespread and cosmopolitan distribution due to their biology. For instance, the North American ancylid Ferrissia fragilis has Biodistribution of the Informal Group Basommatophora 66 been spreading in Europe probably due to its many biological attributes such as its ability to aestivate and survive in stagnant waters, its small size, and even its hermaphroditic life cycle (Walther and others 2006). This may also be the case for the siphonariids. Furthermore, the wide distribution of certain invertebrates between unconnected habitat patches could depend on passive dispersal mechanisms (Bilton and others 2001). For snails like siphonariids, passive dispersal could be done through being carried on the feet or feathers of birds from one body of water to another. Perhaps serving as evidence is basommatophoran snails appearing in the geological record at the Jurassic-Cretaceous boundary 145.5 million years ago, shortly after the origin of birds (Solem 2008). Other forms of dispersal are rafting on aquatic vegetation, marine/brackish larval dispersal phase, stream capture and even by air (e.g. , cyclonic storms) (Purchon 1977). However, there is no clear material linking this to be the reason for the multitude of occurrences of Siphonaria globally or in the Philippines. Figure 1. The basommatophoran families found in the Philippines. Figure 2. The frequencies of basommatophoran genera in the Philippines. P.N.Y. Young and I.K.C. Fontanilla 67 Figure 3 presents the distribution maps of the basommatophoran families found in the Philippines. The maps indicate where the shells were collected or found. It should be noted that some specimens encountered did not have their localities properly identif ied and were therefore excluded. There were 138 individuals (52.07%) from Luzon, accounting for majority of the specimens. Meanwhile, 68 individuals (25.66%) were found in the Visayas and 59 individuals (22.26%), in Mindanao. The data thus demonstrate that the basommatophoran species are distributed all throughout the Philippine archipelago. The distribution is noted to be heterogeneous, with clustering in the Luzon region but still dispersed almost evenly among the island groups. It is noted that the patchy distribution could be due to the limited and sporadic sampling of the basommatophorans in the Philippines. Amongst the tropical countries in the world, the Philippines, with 336 occurrences and 21 genera, ranks third in basommatophoran occurrences, behind Mexico and Congo. Mexico has 623 occurrences and 31 genera while Congo has 339 genera and 19 genera. The Philippines accounts for 8% of the worldwide basommatophoran occurrences out of the 72 countries listed in the GBIF spreadsheet. The Philippines also has 32 endemic species (Table 3); that is, 42.67% of basommatophoran endemic species can be found in the Philippines. Of these, majority are from Planorbidae ( 4 6 . 6 7 % ) a n d Ly m n a e i d a e ( 2 6 . 6 7 % ) . W i t h t h i s m u c h p r o p o r t i o n o f t h e basommatophoran occurrences and endemic species, a more systematic sampling is needed to assess the full biodiversity of the Basommatophora in the Philippines and account for its evolution. One of the endemic species from Lymnaedae is Radix quadrasi. Remigio and Blair (1997) suggested that it may be conspecif ic with R. rubiginosa from Malaysia on the basis of nearly identical mitochondrial 16S rRNA gene sequences and that they are subspecies of the Eurasian R. auricularia, which is also present in the Philippines. However, Correa and others (2010) evaluated 50 lymnaeid taxa using the nuclear ITS- 1 and ITS-2 sequences in addition to the 16S rRNA gene, and they found that, though both R. quadrasi and R. rubiginosa clustered together, they gave very distinct sequences to be considered the same species. Furthermore, both taxa clustered separately from R. auricularia, clearly indicating that they are distinct from R. auricularia. SUMMARY Survey of Basommatophora in the Philippines based on literature and existing collections demonstrates high diversity in comparison to other tropical countries, with 21 known genera and at least 32 endemic species. These values, however, Biodistribution of the Informal Group Basommatophora 68 Figure 3. The distribution map of basommatophorans in the Philippines. P.N.Y. Young and I.K.C. Fontanilla 69 could be a gross underestimate of the true diversity of the group as sampling is sporadic. This warrants further systematic sampling to address this issue. 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APPENDIX Documentation of the basommatophoran specimens found in the National Museum of the Philippines. Scale is in inches (1 inch = 2.54 cm). 1. Radix auricularia 2. Radix philippinensis Biodistribution of the Informal Group Basommatophora 72 5. Myxas cumingiana 3. Lymnaea rubiginosa 4. Lymnaea sp. P.N.Y. Young and I.K.C. Fontanilla 73 6. Indoplanorbis exustus 7. Physastra hungerfordiana 8. Siphonaria atra Biodistribution of the Informal Group Basommatophora 74 10. Siphonaria javanica 11. Siphonaria laciniosa 9. Siphonaria corrugata P.N.Y. Young and I.K.C. Fontanilla 75 14. Siphonaria sirius 13. Siphonaria siquijorensis 12. Siphonaria normalis Biodistribution of the Informal Group Basommatophora 76 _______________ Patrick Noel Y. Young is a graduate from the Institute of Biology, University of the Philippines Diliman, where he received his BS in Biology. Ian Kendrich C. Fontanilla is an Assistant Professor and member of the Invertebrate Museum at the Institute of Biology, University of the Philippines Diliman. He received his PhD in Genetics from the University of Nottingham, United Kingdom. He is also the President of the Malacological Society of the Philippines. 15. Siphonaria sp.