New Information and Reappraisals Concerning Some Alien and Indigenous Snake Records from the Federated States of Micronesia and the Mariana Islands

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New Information and Reappraisals Concerning Some Alienand Indigenous Snake Records from the Federated States ofMicronesia and the Mariana IslandsAuthor(s): Donald W. Buden , Kevin de Queiroz , Johan Van Rooijen , Derek W.Stinson , Gary J. Wiles , and Sabrino RobertSource: Pacific Science, 68(2):287-293. 2014.Published By: University of Hawai'i PressDOI: http://dx.doi.org/10.2984/68.2.8URL: http://www.bioone.org/doi/full/10.2984/68.2.8

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Pacific Science (2014), vol. 68, no. 2:287 – 293 doi:10.2984/68.2.8 © 2014 by University of Hawai‘i Press All rights reserved

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Few species of snakes are known from the western Pacific islands that make up the Fed-erated States of Micronesia (FSM) and the Mariana Islands, compared for example with the species-rich herpetofaunas of the larger islands of Southeast Asia to the west (Das 2010). The breeding land-snake fauna of the FSM consists solely of three species of blind snakes (Typhlopidae), including Ramphotyph­lops braminus, an Asiatic species that has been inadvertently introduced widely throughout the world (McDiarmid et al. 1999, Wallach 2008), and two recently described congeners,

R. hatmaliyeb and R. adocetus, known only from the Ulithi Atoll islands, Yap, and Ant Atoll, Pohnpei, respectively ( Wynn et al. 2012). The Mariana Islands have R. braminus and Boiga irregularis, brown tree snakes (Rodda et al. 1991, Vogt and Williams 2004). Brown tree snakes were introduced to Guam from the Solomon Islands during or shortly after World War II and have since been implicated in the decline and extinction of many of the island’s native birds and lizards (Rodda et al. 1999, Rodder and Lotters 2010, Kahl et al. 2012). They also are responsible for “damage to electrical power infrastructure, loss of pet and domestic animals, human envenomations, higher costs of shipping from Guam, and threats to the tourism industry” (Rodda and Savidge 2007:310). Brown tree snakes have been recorded elsewhere in the Marianas on Saipan and Tinian (Rodder and Lotters 2010) and on Rota (Pacific Island Alien Snake Data-base 2012), but breeding is undocumented in their nonnative range outside Guam. The only other records of snakes from the Mari-anas and the FSM are of a few alien stowaways and occasional sightings of sea snakes ( Wiles 2000, Reed in Neuman-Lee 2011; D.W.B. and D. Taborosi, in prep.).

Among the records of snakes from the FSM and the Marianas are some for which supplementary information surrounding the circumstances of their collection has only recently come to light, and others whose identifications need to be made or reassessed.

New Information and Reappraisals Concerning Some Alien and Indigenous Snake Records from the Federated States of Micronesia and

the Mariana Islands1

Donald W. Buden,2,7 Kevin de Queiroz,3 Johan Van Rooijen,4 Derek W. Stinson,5 Gary J. Wiles,5 and Sabrino Robert6

Abstract: New information is presented on old records of four species of snakes from four different islands in Micronesia. A record of Dendrelaphis caudolineatus from Saipan is reexamined and the specimen reidentified as D. philippinensis, and a snake from Pohnpei previously recorded only as an unidentified species of Dendrelaphis is identified as D. punctulatus striolatus. We also provide supplemen-tary data on circumstances surrounding records of a brown tree snake, Boiga ir­regularis, from Chuuk, and a yellow-bellied sea snake, Hydrophis platurus (Pelamis platura), from Kosrae.

1 Manuscript accepted 17 July 2013.2 Division of Natural Sciences and Mathematics, Col-

lege of Micronesia-FSM, P.O. Box 159, Kolonia, Pohn-pei, Federated States of Micronesia 96941.

3 Division of Amphibians and Reptiles, National Mu-seum of Natural History, Smithsonian Institution, P.O. Box 37012, NHB MRC 162, Washington, DC 20013-7012.

4 Netherlands Center for Biodiversity Naturalis, P.O. Box 9517, 2300 R A Leiden, The Netherlands.

5 Washington Department of Fish and Wildlife, 600 Capitol Way North, Olympia, Washington 98501.

6 FSM Quarantine, Chuuk Station, P.O. Box 455, Weno, Chuuk, Federated States of Micronesia 96942.

7 Corresponding author (e-mail: don_buden@ comfsm.fm).

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We herein identify a species of Dendrela­phis from Pohnpei hitherto identified only to genus, reidentify another Dendrelaphis recorded on Saipan, and provide supplemen-tary information on a brown tree snake re-corded in Chuuk, and a yellow-bellied sea snake, Hydrophis platurus, recorded from Kosrae.

materials and methods

Information on specimen records was ob-tained from data files in the Division of Amphibians and Reptiles, National Museum of Natural History, Smithsonian Institution ( USNM), as well as from gray literature (e.g., government documents and newsletters), unpublished photographs, and notes and rec-ollections of the contributing authors. Men-sural and meristic data used in Dendrelaphis species comparisons are from Van Rooijen and Vogel (2012).

results

Alien Species

ColubridaeBoiga irregularis ( Bechstein, 1802)Brown tree snakes have been recorded twice in the Federated States of Micronesia. One found dead on a cargo container originating from Guam and being offloaded at the sea-port in Pohnpei on 3 November 1994 was de-posited in Smithsonian collections and cata-loged as usnm 339786 ( Buden 2000). Another was reported in an FSM press release as being found on the deck of a cargo ship from Guam while it was docked at the harbor in Weno, Chuuk, on 25 February 2008 (FSM Public Information Office 2009). No additional in-formation was given in the press release, and none has been reported in the scientific litera-ture. One of us (S.R.) was present during the initial investigation and recalls that the snake (~1.0 – 1.2 m long) was found dead and be-lieved to have been crushed to death when the ship weighed anchor at the last port of call in Guam. It was identified as a brown tree snake by Konrad Englberger (Secretariat of the

Pacific Community, Quarantine Consultant) from photographs (e.g., Figure 1A ) taken at the site. The snake was in an advanced state of decomposition when found and was taken to the Chuuk Quarantine Incinerator for disposal.

Dendrelaphis philippinensis (Gunther, 1879)A gravid female snake of the genus Dendrela­phis was collected alive in Saipan by D. Stin-son in May 1990. It was identified as D. cau­dolineatus and thought to have arrived in ship’s cargo from the Philippines that was being stored near where the snake was captured (Fritts et al. 1990, McCoid and Stinson 1991). In light of a recent revision of the D. caudolin­eatus complex ( Van Rooijen and Vogel 2012), K. de Q. reexamined the fluid-preserved spec-imen (usnm 300567) (Figure 1B), along with a photograph that was taken at the time of cap-ture, before the specimen was preserved. In coloration and pattern, the specimen most closely resembles D. terrificus from Sulawesi and, to a somewhat lesser degree, D. philippin­ensis from the Philippines, particularly the more brightly colored examples from South Luzon and Catanduanes (see Van Rooijen and Vogel 2012). In number of ventrals, the Saipan specimen (174) is at the lower range limit for D. terrificus (174 – 181) and slightly above the range limit for D. philippinensis (161 – 172) but well within the range of the lat-ter species if one outlier specimen with 179 ventrals ( Van Rooijen and Vogel 2012) is in-cluded. In number of subcaudals, the Saipan specimen (108) is at the upper range limit for D. philippinensis (94 – 108) but well above the limit for D. terrificus (94 – 102). In relative tail length, the Saipan specimen (0.29) is closer to D. philippinensis (0.25 – 0.29) than to D. terrifi­cus (0.26 – 0.27). A Principal Component Analysis of all those characters that distin-guish D. terrificus from D. philippinensis (fide Van Rooijen and Vogel 2012) shows the Saipan specimen positioned closer to D. phil­ippinensis (Figure 2). Dendrelaphis philippinensis is endemic to the southern Philippine Islands, including Basilan, Mindanao, Cebu, Bohol, Leyte, Samar, Polillo, Kalokot, Cantan-duanes, and southeastern Luzon ( Van Rooi-jen and Vogel 2012).

Figure 1. A, Boiga irregularis found dead on a cargo ship at Weno, Chuuk, FSM; B, Dendrelaphis philippinensis (usnm 300567) found alive on Saipan, Commonwealth of the Northern Mariana Islands; and C, D. punctulatus striolatus (usnm 506906) found in Kolonia, Pohnpei, FSM.

290 PACIFIC SCIENCE · April 2014

Dendrelaphis punctulatus striolatus (Peters, 1867)

Another specimen of the snake genus Dendre­laphis (Figure 1C ) was collected at Kolonia Elementary School grounds on Pohnpei dur-ing the late 1980s. It was kept as a fluid- preserved specimen at the College of Micronesia-FSM for several years before being deposited in the Smithsonian collec-tions (usnm 506906). The circumstances sur-rounding its collection are unclear. Buden (2000) and Buden et al. (2001) recorded it as having been found alive, based on informa-tion received during the mid-1990s from a quarantine officer who indicated that the specimen was alive when first encountered by a groundskeeper cutting grass at the school. By contrast, Fritts (in Jaffe 1994 and Fritts et al. 1999), who first reported on the speci-men and identified it as a Dendrelaphis, was told that it was found dead.

The poor condition of the specimen and the uncertainty of the taxonomy of Dendrela­phis precluded identification as to species when the specimen was first reported. The potential source population of Dendrelaphis nearest to Pohnpei is in Palau. Palau tree snakes (also known as Palau racers) are cur-rently treated as a subspecies, D. punctulatus striolatus, of common tree snakes (also known as Australian or green tree snakes), which occur in Australia and New Guinea. But on-going studies of Indo-Australian and Oceanian populations of Dendrelaphis point to the Palau population as being a separate species ( J.V.R., G. Vogel, and R. Somaweera, unpubl. data). A reexamination of the Pohnpei specimen by K. de Q. affirms that it matches well with mate-rial from Palau in usnm collections and fits the description of the Palau form given by Pe-ters (1867). We provisionally refer the Pohn-pei specimen to the subspecies D. punctulatus

Figure 2. Ordination of 10 Dendrelaphis terrificus from Sulawesi, 29 D. philippinensis from the Philippines, and the specimen from Saipan along the first two principal components based on a Principal Component Analysis of those characters that distinguish D. terrificus from D. philippinensis (ventrals, subcaudals, tail length [Van Rooijen and Vogel 2012]).

Snake Records from Micronesia · Buden et al. 291

striolatus pending formal taxonomic changes within this group.

Native Species

HydrophiidaeHydrophis platurus (formerly Pelamis platura)

( Linné, 1766)Based on the results of a molecular phyloge-netic analysis, Sanders et al. (2013) recently proposed merging the genus Pelamis and seven other hydrophiid genera all under the genus Hydrophis. Yellow-bellied sea snakes are widespread throughout the tropical and sub-tropical Pacific and Indian Oceans (David and Ineich 1999, Heatwole 1999, Sheehy et al. 2012), but there are few records from the FSM ( Buden 2000, 2007) and only one known voucher specimen from Kosrae (usnm 495585). That specimen is recorded as having been donated by Tom Fritts, received from Lew Brooks, and cataloged in October 1995, but the name of the collector, the collection date, and specific locality are lacking. How-ever, in a Brown Tree Snake Update (a dis-continued newsletter that had limited distri-bution and is not readily available in most libraries), under the subheading Pelagic Sea Snake Found on Kosrae, Federated States of Micronesia, Kosaka et al. (1992) remarked on a yellow-bellied sea snake that was found alive on a beach near a freshwater inflow at Mosral, Malem, Kosrae, on 4 March 1992. The snake was preserved in alcohol by staff of the Kosrae Division of Agriculture and Forestry and for-warded to the U.S. Fish and Wildlife Service. Because Fritts, who was employed by the USFWS, did not donate any other Pelamis specimens from Kosrae to the Smithsonian collections, it seems reasonable to infer that the specimen referred to in the newsletter is usnm 495585. This is the only known docu-mented record of H. platurus from Kosrae.

discussion

Of the four species whose records are re-viewed here, only Hydrophis platurus is indig-enous to the area in greater Micronesia where it was found. It is completely pelagic, feeding and reproducing at sea. Land records, or even

those from shallow, inshore waters, are scarce and probably involve weak, injured, or storm-driven individuals. In the FSM, H. platurus has been recorded only from Kosrae, Pohn-pei, Nukuoro Atoll, and Losap Atoll ( Buden 2000, 2007). The three other records re-viewed in this study represent extralimital oc-currences of known invasive (Boiga irregularis) or potentially invasive (Dendrelaphis philip­pinensis, D. punctulatus striolatus) species. The occurrence of these different species from three different sources underscores the vul-nerability of Pacific islands to invasion by alien species: Boiga irregularis reached Pohn-pei almost certainly from Guam, D. philip­pinensis arrived on Saipan probably from the Philippines (likely South Luzon or immedi-ately adjacent areas, where the most vividly colored examples of this species are found), and D. punctulatus striolatus reached Pohnpei from Palau.

acknowledgments

For responding to queries relating to records of snakes from Micronesia, we thank Russell Benford, Carlos Cianchini, Konrad Engle-berger, Tom Fritts, Paul Radley, James Stan-ford, Dan Vice, and John Wichep. We thank James Poindexter, U.S. Geological Survey, National Museum of Natural History, for providing images of the preserved specimens of Dendrelaphis philippinensis from Saipan and D. punctulatus striolatus from Pohnpei, and Shaun Suliol, IT Division, College of Micro-nesia, for the composite of Figure 1.

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