156 



SAMUELSON AND NISHIDA 



TABLE 4 

 Taxa Endemic to the Marshall Islands 



Arachnida 



Pseudoscorpionida 



Garf^pus ornatus Beier — Garypidae (Bikini) 



Xenolpium oceanicurn latum Bsier — Olpiidae (Lae, Ujae, Utirik) 



Insecta 



Heteroptera 



Riptortus saileri Usinger — Coreidae (Kwajalein) 

 Camp^ilomma eniwetok Schuh — Miridae (Enewetak) 



TABLE 5 



Distribution of Insects and 

 Allies Endemic to the Marshall Islands 



-Delphacidae (Ailinglapalap, 



Homoptera 



Ugyops kinbergi magas Fennah- 

 Jaluit) 



Coleoptera 



Ceresium robustum Gressitt — Cerambycidae (Arno) 

 Ceresium unicolor marsballum Gressitt — Cerambycidae (Majuro) 

 Oopsis marshallensis Gressitt — Cerambycidae (various atolls) 

 Prosoplus /libisci Gressitt — Cerambycidae (Majuro, Utirik) 

 Prosoplus major Gressitt — Cerambycidae (Arno) 

 Melanoxanthus lahuersi Van Zwaluwenburg — Elateridae (Arno) 

 Simodactylus marshallensis Ohira — Elateridae (Kwajalein) 

 Chariotheca costata Kulzer — Tenebrionidae (Arno, Ailinglapalap) 

 Tagalus angustus Kulzer — Tenebrionidae (Arno) 



Diptera 



Nocticanace marshallensis Wirth — Canaceidae 

 Dasyhe/ea nigristigmata Tokunaga and Murachi — 



Ceratopogonidae (Ailinglapalap) 

 Dasyhe/ea sp. No. 1 Tokunaga and Murachi — Ceratopogonidae 



(Arno) 

 Forcipomi^ia tuthilli Tokunaga — Ceratopogonidae (Enewetak) 

 Clunio tuthilli Tokunaga — Chironomidae (Enewetak) 

 Cricotopus sp. No. 1 Tokunaga — Chironomidae (Kwajalein) 

 Plastosciara jaluitensis Steffan — Sciaridae (Jaluit) 

 SciJthropochroa trispinosa Steffan — Sciaridae (Kwajalein) 

 Limonia beardsle^/i Alexander — Tipulidae (Namu, Namorik) 

 Limonia sentifera Alexander — Tipulidae (Namu, Arno) 



Hymenoptera 



Cirrospiloideus /ul/atoayj Yoshimoto and Ishii — Eulophidae 

 (Ebon) 



atolls where they are indigenous in the central and eastern 

 Carolines (Yap, Truk, Ponape, Kosrae). None of the 

 Marshalls or Gilberts are correspondingly close to a high 

 island. The high islands of the Carolines are centers of 

 endemism with relatively rich faunas and may have been 

 sources for many of the forms now strictly limited to atolls. 

 Thus, the presence of isolated high islands in the vicinity 

 of atolls may have considerable influence on the nature of 

 an atoll fauna. 



Factors influencing an atoll fauna would include the 

 above, as well as the degree of isolation of the atoll, land 

 area, climate, frequency of typhoons, effects of wind and 

 sea currents, and presence of migratory birds. Finally, 

 human activities have considerable bearing on the nature 



of an atoll fauna; these affect faunal composition through 

 environmental alteration and allow increased opportunities 

 for establishment of adventive species. Direct air and ship- 

 ping routes between the Marshalls and Hawaii have obvi- 

 ously permitted movements of species between the two 

 island groups within the past 40 years (Table 8). Of the 

 adventive elements on Enewetak that also occur in Hawaii, 

 we note that they represent around 28% (54 of 191) of 

 the atoll's fauna. Furthermore, when considering the 

 Enewetak adventives alone, we see that a higher propor- 

 tion, 66%, also occurs in Hawaii (54 of 82). Hawaii, as an 

 example of a center of commerce in the Pacific, has wit- 

 nessed a marked increase of established adventives over 

 recent decades (cf. Beardsley, 1962, 1979), and that is 

 due largely to increased air traffic. 



Gressitt (1954) stated that atolls and low islands in the 

 Carolines, Marshalls, and Gilberts have relatively poor but 

 uniform faunas. This appears so within the Marshalls, at 

 least at the generic level and frequently at the species 

 level, when the adventive forms established on Kwajalein 

 and Enewetak Atolls are discounted. 



Zoogeography 



The geographical affinities of major groups represented 

 in the Marshall Islands, or otherwise in Micronesia, are 

 only partly ascertained at this time. Many groups are not 

 yet studied to the point where they can be analyzed defini- 

 tively This is also true for the faunas of adjacent regions; 

 all have influences on the Micronesian fauna through past 

 or present movements of species. 



In the following discussion, the general geographical 

 distributions are given for all species reported for the 

 Marshall Islands to classify the potential inventory and 

 sources of the species for Enewetak Atoll. The numbers of 

 species counted for the Marshalls and Enewetak are pro- 

 vided at the beginning of most of the following sections. 

 Also, most major groups occurring in Micronesia are sum- 

 marized to give some perspective to the Marshall Islands 

 fauna; this includes, when known, the number of species 

 or subspecies reported for Micronesia and the percentage 



