MORPHOLOGY,SYSTEMATICS,EVOLUTION Whartonacarus floridensis sp. nov. (: Trombiculidae), With a Taxonomic Review and the First Record of Whartonacarus Chiggers in the Continental United States

1 2 2 JAMES W. MERTINS, BRITTA A. HANSON, AND JOSEPH L. CORN

J. Med. Entomol. 46(6): 1260Ð1268 (2009) ABSTRACT Among several unusual species collected during surveillance of ectoparasites on wild- life hosts in the southeastern United States and Caribbean Region, the larvae of a new species of Whartonacarus were encountered in 2003 on a cattle egret, Bubulcus ibis (L.), in the Florida Keys. This is the Þrst record for a member of Whartonacarus in the continental United States. The is described and named as Whartonacarus floridensis Mertins, and the possible signiÞcance of this discovery with respect to the “tropical bont ,” Amblyomma variegatum (F.), is discussed. A brief taxonomic review of Whartonacarus raises questions about the putative synonymy of Whartonacarus nativitatis (Hoffmann) and Whartonacarus thompsoni (Brennan) and suggests that Whartonacarus shiraii (Sasa et al.) may include two distinct taxa. Whartonacarus is redeÞned, and a revised key to the known taxa is provided. Toritrombicula oceanica Brennan & Amerson is placed in the genus Whartonacarus. Also, Whartonacarus palenquensis (Hoffman) is rejected as a member of this genus and placed in its own new genus, Longisetacarus Mertins.

KEY WORDS Whartonacarus floridensis sp. nov., Longisetacarus gen. nov., Amblyomma variegatum, chiggers, cattle egret

Since the 1960s, the United States Department of Ag- Rico, and the Virgin Islands. Targeted survey sites are riculture (USDA), and Plant Health Inspec- natural areas where introduced exotic tion Service, Veterinary Services and the Southeastern might be most likely to survive and establish them- Cooperative Wildlife Disease Study have jointly par- selves unobserved on wildlife hosts. Most surveillance ticipated in a cooperative program of surveillance for activity involves examination of live-captured wildlife, exotic and other potential livestock pest arthro- collection and preservation of perceived ectopara- pods in the United States and the Caribbean Region. sites, and subsequent identiÞcation of the collected In recent years, these efforts have intensiÞed with a specimens. When opportunities arise, ectoparasites growing appreciation of the potential for introduction also are collected from road-killed wildlife, injured or of exotic ticks and other livestock arthropods and the dead animal hosts at wildlife rehabilitation facilities, or associated threat to American agriculture. During the other sources, as available. last half-century, at least 99 species of exotic ticks were In the past 6 yr, we have collected ectoparasites either detected or destroyed at U.S. ports of entry, or from Ͼ7,800 wildlife hosts, and although the labora- they were inadvertently introduced into the United tory processing of the specimens is far from complete, States (Keirans and Durden 2001). Furthermore, the we already have identiÞed Ͼ130 different agent of heartwater disease, Ehrlichia ruminantium species from these samples. Among them, we have (Cowdry), and its major vector, the “tropical bont recognized several undescribed new species, several tick,” Amblyomma variegatum (F.), are present on interesting new host and distribution records for var- several islands in the Caribbean (Barre et al. 1987, ious ectoparasites, and numerous expected hostÐpara- Pegram et al. 2004), and a potential for interisland site associations. Herein, we report on one of the most transport of the ticks by the cattle egret, Bubulcus ibis interesting and possibly signiÞcant parasite collec- (L.), has been demonstrated previously (Corn et al. tions, the Þrst collection record of chiggers belonging 1993). to the genus Whartonacarus in the continental United Our current emphasis in Þeld surveillance activities States. These were taken from a cattle egret, and is in Alabama, Florida, Georgia, Mississippi, Puerto they represent a new species described herein.

1 Corresponding author: U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, National Materials and Methods Veterinary Services Laboratories, 1800 Dayton Ave., Ames, IA 50010. 2 Southeastern Cooperative Wildlife Disease Study, College of Vet- Collection and Study of Specimens. Following the erinary Medicine, University of Georgia, Athens, GA 30602. standard procedures in our ongoing ectoparasite sur- November 2009 MERTINS ET AL.: W. floridensis SP. NOV., WITH A GENERIC REVIEW 1261 veillance on wildlife, in August 2003, one of our Þeld Vercammenia (Whartonacarus), Vercammen-Grand- assistants examined a frozen adult B. ibis carcass held jean 1971: illustration; Vercammen-Grandjean et al. at the facilities (since closed) of Wildlife Rescue of the 1973: illustration. Florida Keys in Key West, FL. The exact origin and Whartonacarus, Brennan and Goff 1977: 561; Domrow collecting circumstances of the host carcass are un- and Lester 1985: 7, 12; Hoffmann 1990: 14. certain, but based upon policies of the rescue facility, it probably was found/captured in the Lower Type Species. thompsoni Brennan 1953 KeysÑor even locally in Key WestÑshortly before (ϭTrombicula nativitatis Hoffmann 1950). examination. Five small mites were found attached to Diagnosis. Trombiculinae: Trombiculini. Larval the bird, placed in 70% isopropyl alcohol, and shipped stage parasitic on water birds. Idiosoma ovoid, with a to the USDA National Veterinary Services Laborato- typically striate cuticle overall. Small to moderate size, ries in Ames, IA, for identiÞcation. All the mites were overall body length 330Ð645, width 240Ð500. Scutum routinely processed further by mounting together un- roughly rectangular, with anterolateral shoulders, der a coverslip on a microscope slide in HoyerÕs so- thin ßagelliform sensillae, and possibly a few poste- lution in November 2003. rior epiostracal striae; Þve branched scutal setae, After several days delay for clearing of the speci- PLϾALϾAM. Eyes large, two pairs on ocular plates. mens in the mountant, J.W.M. examined them at 400ϫ Cheliceral blade with tricuspid apex; galeala nude. with a Leitz Orthoplan compound microscope (Leica Palpal tarsus with seven branched setae, a subter- Microsystems, DeerÞeld, IL) equipped with differen- minala, and a long, slender basal tarsala; tibial claw tial interference contrast illumination and an ocular bifurcate, with axial prong internal; femoral seta micrometer. The specimens were identiÞed and con- branched, genual seta sparsely branched or nude, and Þrmed as members of the trombiculid genus Whar- all three tibial setae nude. Humeral setae, one or two tonacarus, using keys in Brennan and Goff (1977) and pairs. Dorsal hysterosomal setae very numerous, 32Ð Vercammen-Grandjean (1968). Supplemental infor- 130. Ventral idiosomal setae numerous, with two or mation in these sources and others (Brennan and three pairs of sternals and 50Ð98 opisthosomals. Legs Jones 1959, Goff 1989) suggested ours was a new 7-7-7, with all coxae usually unisetate (some coxae III distribution record. Hoffmann (1990), Loomis (1966), bisetate); 3Ð4 genualae I (typically 3), 1Ð5 genualae II and Wharton (1945) enumerated the Þve recognized (typically 1), and 1Ð8 genualae III (typically 1); 1 species of Whartonacarus, conÞrmed distribution of tibiala III; 1 nude mastitarsala III. the genus only outside of the continental United Discussion. The possession of both large eyes and States, and provided strong evidence that the Florida cuticular striae encroaching on the scutum (i.e., specimens were undescribed. The novelty of our chig- epiostracal) is a typical combination for avian- gers was established by comparing them to the original parasitic chiggers (Vercammen-Grandjean 1968). descriptions and redescriptions of each of the known All species included here in Whartonacarus have Whartonacarus spp. (Wharton 1945; Hoffmann 1950, large eyes, but among them, only the new species, 1965, 1990; Sasa et al. 1952; Brennan 1953; Sasa and W. nativitatis (feature described but not illus- Jameson 1954; Loomis 1966). trated), and Toritrombicula oceanica Brennan and Conventions. Most of the terminology used herein Amerson (a prospective new addition) are known to follows Goff et al. (1982). All measurements in the have such epic-stracal striae. However, this charac- descriptions are in micrometers, unless otherwise ter well may have been overlooked by the authors stated. of other species because it is not so evident in the Repository. The specimens in the type series for the present taxon as in some other genera from birds; it new species are deposited in the U.S. National Mu- is tentatively included here in the generic diagnosis. seum of Natural History, Smithsonian Institution, Washington, DC. Authorship. Taxonomic decisions herein and au- Whartonacarus floridensis Mertins, sp. nov. (Fig. 1) thorship of new taxa are attributable to J.W.M. alone. Type Material. Five engorged larvae, all mounted on one slide. All are damaged and incomplete to some extent, including the worst specimen that consists of Results only the opisthosoma and one leg III. The best spec- The new chigger larvae possess the characteristic imen is complete, except for one leg III missing be- morphological features of Whartonacarus, as detailed yond the trochanter; this specimen is hereby desig- in the following generic diagnosis. nated as the holotype. The gnathosoma is present on only one other specimen, and most details of the palptarsi on both specimens are obscured by adher- ent extraneous materials. HOLOTYPE: 1 , Key Whartonacarus Vercammen-Grandjean 1960 West, Monroe Co., FL, 19-VIII-2003, on Bubulcus Neacariscus (Whartonacarus) Vercammen-Grandjean ibis, Larry Seal collector. PARATYPES: 4 larvae, 1960: illustration. same data. Toritrombicula (Whartonacarus), Loomis 1966: 768; Distribution. This is the only collection known to Vercammen-Grandjean 1968: 29, 79. date. 1262 JOURNAL OF MEDICAL ENTOMOLOGY Vol. 46, no. 6

scutum by a distance approximately equal to diameter of anterior eye; anterior eye largest and subcircular, maximal diameter on holotype 31 (mean of all 30), height (measurable on two paratypes) 12; maximal diameter of oval-shaped posterior eye 19 (mean of all 20). Dorsal hysterosoma with numerous short- branched setae, similar to scutals, and comprising hu- merals (2-2) plus 96 dorsals on holotype (mean of type series 92), arrayed in seemingly unordered manner; lengths of humeral seta (holotype) 94, laterodorsal 72, mediodorsal 64. Sternal setae 2, 2; 82 ventral hystero- somals on holotype (mean of type series 75), randomly arrayed; branches on ventral idiosomal setae moder- ately longer than on dorsals, longest and less appressed on Þrst pair of sternals; lengths of sternal seta I (ho- lotype) 68, sternal II 58, medioventral 40, posterov- Fig. 1. Scutum and eyes of W. floridensis sp. nov. Scale entral 65. All leg segments at least moderately punc- ϭ ␮ bar 50 m. (Online Þgure in color.) tuate; each tarsus ending in two simple pretarsal claws and a clawlike empodium. Coxae densely punctuate, Etymology. Named for the collection locality in the I and II contiguous, with usual Clapare`deÕs organ be- U.S. state of Florida. tween; coxa III separated posteriorly; one branched Diagnosis. SpeciÞc unique features of the new chig- seta on each coxa, posteriorly on coxae I and II, an- ger within the genus Whartonacarus are larger size, teriorly on coxa III. Distribution of branched setae on anterior scutal carina, two genualae II and III. remaining leg segments follows usual pattern (Goff et Larval Description. Total body length of holotype al. 1982). Distribution of specialized leg setae: three 645, and one paratype, the same; maximal width of genualae I, two genualae II, two genualae III; two holotype 527, and mean width of it plus two paratypes tibialae I, two tibialae II, one tibiala III; one tarsala I, 494. Cuticular striae well-developed over most of the one tarsala II, one nude mastitarsala III; nude parasub- ßexible surface area, especially anterodorsally; striae, terminala and subterminala on tarsus I; one pretarsala in places, sometimes consisting of rows of tiny, close- on each tarsus I and II. set cuticular tubercles, especially posteriorly. Anus in approximate center of ventral hysterosoma. Gnatho- Discussion base moderately punctate, with a ventral pair of mod- erately branched setae anterolaterally; palpal femur Whartonacarus Bionomics. Although the collection with a highly branched seta, genual seta sparsely circumstances of our W. floridensis specimens do not branched, all three tibial setae nude; at least some provide much notable ecological information, cumu- palptarsal setae branched, but details not discernible; lative published data for collections of the other Whar- tarsala long (30) and thin; palpal claw bifurcate, axial tonacarus spp. allow us to make some tentative gen- prong internal; galeala nude; palpfemur, genu, and eralizations about the distribution, hosts, habits, and tibia moderately punctate. Cheliceral base highly biology of these chiggers. punctate, blade slightly curved, with tricuspid apex. With the exception of W. palenquensis (Hoffmann Scutum (Fig. 1) approximately rectangular, with an- 1965), all known collections of Whartonacarus, includ- teromedial margin slightly produced at AM, a bit more ing W. floridensis, have come from dry coastal areas, so (shoulders) at each AL, prominently and narrowly from islands, or at sea, e.g., , Florida Keys, produced around each PL, and posterior scutal margin Guam, Jamaica, Japan, , mid-PaciÞc Ocean, slightly and evenly convex; surface prominently punc- Okinawa, and Trinidad (Wharton 1945; Hoffmann tate, except less so in a small, fusiform area surround- 1950, 1990; Sasa et al. 1952; Brennan 1953, 1966, 1967; ing AM; posterior margin of this area marked by a Sasa and Jameson 1954; Loomis 1966; Domrow 1966, cuticular ridge that extends laterally to each AL along 1978). Even the coastal desert collections of three anterior scutal margin. Posterior scutal margin sub- species in Sonora, Mexico, were possibly attributable sumed by two to six cuticular striae. All Þve scutal to host infestations that may have originated on nearby setae bearing many short, largely appressed branches rocky islands (Loomis 1966). The unique inland col- along their entire lengths; sensillary bases in posterior lection locality for W. palenquensis from a common half of scutum on a line slightly anterior to the PL line; rainforest bat, Saccopteryx bilineata (Temminck) each sensilla long, thin, tapering to its apex, and bear- (Emballonuridae), in Palenque, Chiapas, Mexico ing three or fewer short, appressed barbs in distal half. (Hoffmann 1965), is anomalous and is discussed fur- Standard scutal data for holotype (with means for four ther herein. specimens, as available) are as follows: AW Ð 92 (96), The majority of host records for Whartonacarus PW Ð 107 (110), SB Ð 41 (43), ASB Ð 41 (37), PSB Ð 18 chiggers comprise water birds, including seabirds (19), AP Ð 36 (36), AM Ð 67 (67), AL Ð 60 (57), PL Ð (Sternidae, two species), shorebirds (Charadriidae, 96 (89),SÐ97(95), SD Ð 61 (55). Eyes large, 2-2, each three species; Hematopodidae, one species), and wad- pair on an ocular plate and laterally separated from ing birds (Scolopacidae, Þve species) (Wharton 1945, November 2009 MERTINS ET AL.: W. floridensis SP. NOV., WITH A GENERIC REVIEW 1263

1946; Hoffmann 1950, 1990; Sasa et al. 1952; Brennan ing the tropics for Arctic breeding grounds (Watanabe 1953; Sasa and Jameson 1954; Loomis 1966; Domrow 1991, Wiersma and Wiersma 1996), and the chiggers 1966). All of the preceding families are members of the probably were recently acquired in the birdsÕ tropical avian order Charadriiformes; our record of W. flori- overwintering habitats. We think that present records densis from a cattle egret adds a new family of wading may only hint at the true situation, however, and more bird hosts (Ardeidae) in a different avian order (Cico- intensive efforts to examine suitable avian hosts in niiformes) to the host list. The cattle egret is physically similar tropical habitats worldwide might greatly ex- the largest known host for Whartonacarus. pand the area where Whartonacarus chiggers are Four nonavian hosts for Whartonacarus chiggers are known to occur. documented. The type host for W. nativitatis was a None of the reported individual collections of common side-blotched lizard, Uta stansburiana Baird Whartonacarus is very large (range, 1Ð15 larvae), and & Girard (Iguanidae), on PaciÞc Coastal Isla Nativ- some species are known from only the type collec- idad, Baja California Sur, Mexico (Hoffmann 1950). tions, so these chiggers may not be very common Isla Natividad is an arid offshore island hosting millions anywhere. Because of the vagility of their avian hosts, of roosting and/or nesting seabirds that probably are locality collection records for these larval chiggers do the usual hosts for W. nativitatis, and indeed, Loomis not necessarily reßect the actual endemic habitats (1966) cites later collections of this chigger (as W. where they maintain permanent residency and com- thompsoni) from two shorebird species in coastal So- plete life cycles. Although the published locality nora, Mexico, on the Sea of Cortez (Gulf of Califor- records are few, we may infer from them at least three nia). Domrow (1978) found W. shiraii (Sasa et al. relatively circumscribed areas where sustained Whar- 1952) on an endemic rodent host, Rattus leucopus tonacarus populations are likely to occur. Guam, in the (Gray) (Muridae), in the dry season on the eastern west central PaciÞc Ocean, is one of them. It is the coast of Cape York, Queensland, Australia; the two documented collection site for two species of Whar- engorged larvae were characterized as stragglers on tonacarus larvae and the speciÞc locality with the most this host. The marine Þsh-eating bat Pizonyx vivesi individual collections on the greatest variety of bird Menegaux (Vespertilionidae) is a third nonavian host hosts (Þve species) (Wharton 1945, 1946; Loomis recorded for W. nativitatis (Brennan 1966). This 1966). Only two collections (Domrow 1966, 1978) of unique collection of one mite was from Isla Partida, W. shiraii are known from east coastal sites of northern Sonora, Mexico, in the Sea of Cortez, where this bat Queensland, Australia, but one of them is from a native shelters in rocky crevices among cacti on barren rodent, and infestation of this resident aberrant host slopes. These sites also contain nests of black storm- suggests that the chiggers must be present locally in a petrels, Oceanodroma melania (Bonaparte) (McLel- breeding population. Similarly, aberrant infestations lan 1927, Reeder and Norris 1954), which by inference of a native lizard (Hoffmann 1950) and an endemic bat probably are the normal hosts for the local chiggers (Brennan 1966) on two northwestern Mexican islands (Brennan 1966). Finally, as previously mentioned, the strongly suggest that Whartonacarus chiggers maintain type host for W. palenquensis is a Mexican sac-winged permanent populations there, as well. In fact, this area bat (Hoffmann 1965), a problematic host for other of the central Baja California Peninsula, coastal So- reasons to be discussed later. nora, and adjacent islands in the PaciÞc Ocean and Sea The habits and biologies of Whartonacarus spp. are of Cortez that is Ϸ400 km across is known to host a little known beyond speculative inferences. Nearly all greater variety of Whartonacarus spp. chiggers on of the recorded avian hosts for these chiggers are more kinds of hosts than anywhere else in the world notably vagile species that usually follow long-range (Hoffmann 1990). The speciÞc environmental micro- migration patterns. Chiggers specializing in feeding on habitats of Whartonacarus spp. are unknown, but some such hosts have the potential for an equally wide- known hosts [e.g., Charadrius wilsonia (Ord), Pluvia- ranging geographic distribution (Wharton 1945), and lis squatarola (L.)] rarely stray far from mud ßats, sand the scattered Whartonacarus collection records from bars, and sandy beaches in the tropics. Loomis (1966) coastal and insular areas of East Asia and Australia, all suggests that infestation sites might be in seabird roost- the way to the Caribbean Sea, provide some evidence ing areas on rocky cliffs and offshore islands. He fur- in support of this idea, at least longitudinally. A syn- ther notes that individual larvae of other chigger gen- thesis of all the reported collection localities, however, era with similar hosts and morphologies are known to especially those of nonmigratory hosts, shows that shelter in small rock holes or crevices. Whartonacarus chiggers are all but restricted to trop- Taxonomic Review of Whartonacarus. This new ical latitudes (Wharton 1945, 1946; Hoffmann 1950, chigger species most resembles W. nativitatis (sensu 1990; Sasa et al. 1952; Brennan 1953, 1966, 1967; Sasa Hoffmann 1950), from which it differs in body size and Jameson 1954; Loomis 1966; Domrow 1966, 1978). (645 versus 412), number of genualae II and III (two The only collections notably outside the tropics are versus one), total number of hysterosomal setae (dor- two from Japan, both on PaciÞc golden plovers, Plu- sal ϩ ventral ϭ 178 versus 210), and the nature of the vialis fulva (Gmelin) (Sasa et al. 1952, Sasa and Jame- sensilla (few distal barbs versus nude). In addition, son 1954). A collection date is included for only one Hoffmann (1950) originally described the palptarsal of these acquisitions, but together, the host and tem- setal formula for W. nativitatis as 8B, an obvious lapsus poral evidence strongly suggest that the Japanese col- for 7BS; the formula for W. floridensis is, unfortu- lections were from transient spring migrant birds leav- nately, indeterminate, but as for W. nativitatis, it prob- 1264 JOURNAL OF MEDICAL ENTOMOLOGY Vol. 46, no. 6 ably agrees with all of the other described congeners, ent, as well, with those on W. nativitatis seeming i.e., 7BS. shorter overall and with longer, more prominent If one accepts the synonymy of W. thompsoni with branches, and those on W. thompsoni seeming rela- W. nativitatis (Hoffmann 1990), then the sensillae of tively longer overall and shorter-branched. The de- the combined entity may display a few distal barbs, gree of these discrepancies that is due to artistic li- like W. floridensis. However, the conspeciÞcity of the cense can be determined only by direct examination former two taxa and even the consistency of all the and comparison of the type specimens. The same is specimens called similar by Loomis (1966) are open to true of a few other small disparities between the re- question. It is true that, beyond the barbed/unbarbed spective descriptions of the two taxa, notably the na- nature of the sensillae, one can Þnd little in the pub- ture of the parasubterminalae, the presence of epios- lished descriptions of the two taxa to distinguish them tracal striae on the scuta, and the aforementioned from one another. However, one evident primary dis- nature of the sensillae. Parasubterminalae are nude in parity lies in the reported numbers of hysterosomal W. nativitatis but not mentioned in the descriptions of setae. Brennan (1953) states that his unique W. thomp- W. thomponsi; scutal striae are described (but not soni type specimen from Jamaica has “about 80” dorsals illustrated) for W. nativitatis and not mentioned for and “about 80” ventrals; his illustration implies the W. thompsoni; the sensillae of W. nativitatis are de- respective numbers are 80 and 70. Hoffmann (1950) scribed as nude and those of W. thompsoni as with a gives these respective numbers on her type specimen few apical branches. Any or all of these differences of W. nativitatis from Baja California Sur, Mexico, as may be the result of simple descriptive oversights by “approximately some 130” and “some 80”; her illustra- the original authors, or they could represent real spe- tions show 125 dorsals and 84 ventrals. Loomis (1966) ciÞc morphological distinctions. Our purpose here is studied three Whartonacarus larvae from coastal So- not to formally deny the synonymy of W. nativitatis nora, Mexico, claiming they agreed with the descrip- and W. thompsoni but simply to point out a need for tion of W. thompsoni. He gave the respective numbers re-examination of the issue. It may be that the two of dorsals and ventrals (possibly as means of three entities are, in fact, separate species, with HoffmannÕs specimens?) as 76 and 60. The Þrst number may or may specimens representing one and those studied by not include the four humerals; the authorÕs text is Brennan and Loomis representing the other. unclear. Other measurements and characters given by A few similar troubling questions arise with respect Loomis for his Sonoran specimens, indeed, are also to some of the other Whartonacarus taxa. For example, close to those given by Brennan in his description of Loomis (1966) asserts that a single Whartonacarus W. thompsoni from Jamaica. larva he studied from Sonora, Mexico, is close to and Observed numbers of hysterosomal setae are not conspeciÞc with W. shiraii from Japan, even though necessarily deÞnitive speciÞcally for chiggers, espe- some of the standard scutal data in the respective cially for such hirsute taxa. When they are relatively descriptions seem widely disparate. And the reported few, body setal counts may be very useful taxonomi- variance in the numbers of body setae between the cally, but Vercammen-Grandjean (1968) states that, in Japanese and Mexican specimens is even more con- the range of 100Ð200 body setae, the “law of great cerning. Illustrations in the original description of W. numbers” suggests that actual counts “may show sub- shiraii (Sasa et al. 1952) suggest 70 dorsals and 88 stantial variations.” This statement implies that differ- ventrals; in the English redescription (Sasa and Jame- ences between conspeciÞc specimens may trace to son 1954), the respective illustration-implied numbers natural biological variation and/or simply to the me- are 88 and 98. Loomis (1966) states his respective chanical difÞculty in accurately counting such setae counts are 44 (without accounting for the humerals) through a microscope. Nevertheless, a disparity in the and 44. The numerical disparities here are even numbers of dorsal body setae (e.g., HoffmannÕs W. greater than those previously discussed for W. nativi- nativitatis holotype versus the cited Jamaican and So- tatis versus W. thompsoni, with the Japanese dorsal noran W. thompsoni specimens) in the range of Ͻ55% counts exceeding the Mexican counts by either 59 or seems a difference better characterized as signiÞcant 100%, and the ventral counts exceeding those from rather than substantial. Mexico by either 100 or 123%. Similar published data Beyond the body setal counts are several less ob- are not given for the Okinawan and Guamian speci- jective disparities between descriptions of the two mens mentioned by Loomis (1966), nor for any of the taxa. Brennan (1953) states that at least the dorsals of Australian specimens (Domrow and Lester 1985), but W. thompsoni are arranged in irregular rows, but Hoff- the body setal counts for the Mexican specimen sug- mann (1950) says they are in a nonuniform pattern on gest it, at least, may be something other than W. shiraii W. nativitatis. Moreover, the dorsals on W. thompsoni (sensu Sasa et al. 1952). are said to be all of uniform length, whereas those on The true conspeciÞcity of putative specimens of W. nativitatis are described as longest anterolaterally, Whartonacarus anous (Wharton) also should be in- shorter posteriorly, and shortest anteromedially. In vestigated by reexamination and direct comparison. the illustrations accompanying the two respective This species is the least hirsute in the genus in terms original descriptions, it is not only the numbers of of body setal counts; Wharton (1945) cites 30 dorsals dorsal setae that look very different; the relative and Ϸ50 ventrals in his original description of speci- lengths and extents of the branching on the respective mens from Guam, with an accompanying illustration body setaeÑboth scutal and extrascutalÑlook differ- implying 30 and 48, respectively. Sasa et al. (1952) November 2009 MERTINS ET AL.: W. floridensis SP. NOV., WITH A GENERIC REVIEW 1265 illustrate a similar specimen from Japan, suggesting 33 chigger larvae at the generic level, and this many dorsals and 50 ventrals, and Sasa and Jameson (1954) departures from the norm probably mean something. illustrate what may be the same specimen, with 34 and Indeed, to identify W. palenquensis as a member of the 52 setae implied, respectively, although the accompa- genus Whartonacarus, Hoffmann (1990) had to hedge nying description cites 32 dorsals. All of these numbers in her generic deÞnition and construct her generic key seem similar enough to accept as equivalents, but the with the genus name as an outcome in two divergent illustrated morphological details for some of the other couplets, one (number 9) for W. palenquensis and the features of the respective Guamian and Japanese spec- second (number 18) for all the others. Moreover, in imens raise some doubts about their congruity. For her key to the Mexican species of Whartonacarus, example, the illustrated shape and size of the external Hoffmann immediately (in the Þrst couplet) separates accessory prong on the palptibial claw of WhartonÕs W. palenquensis from all the others by means of two type specimen seems considerably different and larger generically deÞnitive characters. Although it is not our than the same structure illustrated by Sasa et al. (1952) intent here to revise the genus Whartonacarus, J.W.M. and Sasa and Jameson (1954) on their Japanese ma- believes that the enumerated characteristics of W. terial. In addition, the illustrated structural details for palenquensis provide sufÞcient reason for its rejection the scutal and body setae of the Guamian and Japanese as a bona Þde member of the genus. The generic specimens seem noticeably at variance. In both ren- diagnosis given hereinbefore is modiÞed from the derings of the Japanese setae, they seem more en- most recent broad one given by Hoffmann (1990) and larged and less clearly branched basally, and the restated more traditionally and narrowly enough to branches seem shorter and more appressed distally accomplish this move. than is shown in the illustrations of the Guamian mites. Because W. palenquensis clearly does not belong in Moreover, the illustrated scutal shapes of the respec- Whartonacarus, and no other suitable name is avail- tive chiggers differ at the posterolateral corners (i.e., able, J.W.M. chooses to create a new genus to accom- produced around the PL bases versus gently curved) modate this unusual chigger, with the following diag- and in the medial posterior margins (i.e., slightly con- nosis based on characters described or implied by vex versus slightly concave). The recorded hosts for Hoffmann (1965). the Japanese and Guamian mites are the same, but these morphological disparities raise doubts about whether the mites themselves are the same. Whartonacarus dupliseta (Loomis) seems a typical Longisetacarus, gen. nov member of the genus except for its unusually hirsute Trombicula (Trombicula), Hoffmann 1965: 1. legs (Loomis 1966). It is the only included species with Whartonacarus, Hoffmann 1990: 119. nearly consistent bisetate coxa III, and it has more genualae on each leg than any other congener. It is Diagnosis. Trombiculinae: Trombiculini. Larval known from only the type collection. stage parasitic on bats. Idiosoma ovoid. Medium size; As suggested, W. palenquensis seems not to agree overall body length 625, width 445. Scutum subpen- with its putative congeners in many respects. Ecolog- tagonal, lightly punctuate, with slight, rounded, me- ically, it is the only species with no demonstrated dial anterior angle, anterolateral shoulders, and thin, connection to water birds (or any bird hosts), and it nude ßagelliform sensillae; AM base entirely anterior is the only species collected from an inland and for- to AL line; sensillary bases mutually approximate and ested habitat. Morphologically, the differences from close to posterior scutal margin; Þve short-branched other Whartonacarus spp. are numerous and probably scutal setae, AMϾPLϾAL. Without eyes. Palpal tarsus signiÞcant. Although the scutal shape is originally de- with seven branched setae and a moderately long basal scribed as roughly rectangular (Hoffmann 1965), il- tarsala; tibial claw bifurcate, with axial prong internal. lustrations of it (Hoffmann 1965, 1990) suggest that it Legs with two genualae I, one genuala II, and one is better characterized as subpentagonal and certainly genuala III; 2 tibialae I, two tibialae II, and one tibiala not rectangular in the same sense as other Whar- III; tarsus I with a somewhat elongate tarsala, a sub- tonacarus spp. descriptions. Illustrated punctations on terminala, a short and nude parasubterminala, and one the scutal surface look to be less dense than in illus- pretarsala; tarsus II with tarsala and one pretarsala; no trations of other Whartonacarus spp. The relative mastitarsala III. lengths of the scutal setae (AM longest) on W. palen- Type Species. Trombicula palenquensis Hoffmann quensis differ from those (PL always longest) for all 1965: 14 (by monotypy and present designation). other species of Whartonacarus. All described species Distribution. Known only from the type collection of Whartonacarus have two pairs of large eyes, but W. and locality in Palenque, Chiapas, Mexico, on Saccop- palenquensis is eyeless. Other described Whartonaca- teryx bilineata, 13-XII-1950, A. Barrera, collector. rus spp. have a palptarsal formula of 7BS, and their Disposition. The holotype is housed in the collec- palptibiae are N-N-N, but W. palenquensis shows 7B tion of Anita Hoffmann at the Laboratorio de Acaro- and N-N-B, respectively. All other Whartonacarus logõ´a, Universidad Nacional Auto´noma de Me´xico, have at least three genualae I and a single nude mas- Me´xico, D.F. (Hoffmann 1993). titarsala III; W. palenquensis has two and none, re- Etymology. Named for the unusually long AM seta spectively. Many of these characters are listed by Ver- on the scutum (longi- ϩ seta) plus the Latinized Greek cammen-Grandjean (1968) as useful in deÞning word for mite (acarus). 1266 JOURNAL OF MEDICAL ENTOMOLOGY Vol. 46, no. 6

Discussion. Although the absolute lengths of scutal (Brennan and Amerson 1971). The authors illus- setae in chiggers may vary considerably among species trateÑbut do not describeÑa few epiostracal setae within a genus, the comparative lengths of the AL, encroaching on the posterior margin of the scutum, as AM, and PL relative to each other are frequently seen in some other Whartonacarus. None of the other constant and diagnostic at the generic or group level features described or illustrated for this chigger would (Vercammen-Grandjean 1968). Trombiculid genera exclude it from Whartonacarus, but one described and and species with AMϾPL are few and very uncom- one illustrated feature disallow it as a member of mon, and in nearly all chiggers, PL are the longest Toritrombicula (s.s.); the palptibial claw is bifurcate setae on the scutum. As described and illustrated by (trifurcate in Toritrombicula) and the parasubter- Hoffmann, AMϾSD (by 34%), as well, a condition minala is shown as nude (absent or branched in To- seen in numerous other genera and species, but when ritrombicula). The authors do not specify which prong combined with AMϾPL (by 77% in L. palenquensis), of the claw is axial, but based on all of the other the relative length of AM here is unparalleled, at least evidence presented, one would presume it to be in- in . ternal, and T. oceanica is almost certainly a true mem- In HoffmannÕs generic key to Mexican chiggers ber of Whartonacarus. J.W.M. hereby reassigns it as (Hoffmann 1990), L. palenquensis did not track with such. We note also that its host, P. fulva, is a known the other species of Whartonacarus; instead, it ran host for two other Whartonacarus spp., W. anous on through to its own unique terminus. Attempts to iden- Guam (Wharton 1946) and Miyake Island, Japan (Sasa tify this chigger using keys to North American species and Jameson 1954), and W. shiraii on Guam (Loomis (Brennan and Jones 1959) lead to a catch all genus, 1966) and near Tokyo, Japan (Sasa et al. 1952). Trombicula (sensu lato), which is where Hoffmann Identification. The following key summarizes some (1965) originally described it, before she moved it to of the preceding observations, taxonomic concerns, Whartonacarus. Running it through the generic key to and nomenclatural issues, and it provides a means to chiggers of the Western Hemisphere (Brennan and separate the valid and possible speciÞc taxonomic en- Goff 1977) brings one to Toritrombicula, a genus in tities herein discussed. The deÞnitive status of some of which it clearly does not Þt, either (e.g., it lacks eyes, these forms is uncertain and pending until the respec- has a two- not three-pronged palpal claw, nude not tive actual specimens can be studied and compared. branched or absent parasubterminala, PL not longest scutal seta, body size smaller than usual, nonavian host; Nadchatram 1967, Nadchatram and Dohany 1974). One possible resolution for this problem might Key to Prospective Specific Forms of be to temporarily remand W. palenquensis to Trom- Whartonacarus bicula (sensu lato) until someone has an opportunity 1. With genualae I ϭ 3, II ϭ 1, III ϭ 1 ...... 2 to study the unique type specimen. Creation of Longi- Genuala formula otherwise ...... 7 setacarus preempts such an interim solution. Finally, Toritrombicula oceanica Brennan and Am- 2. (1.) Humeral setae 2Ð2; from North American erson was described from two specimens on a PaciÞc localities (thus far) ...... 3 golden plover, Pluvialis fulva, taken at sea near the Humeral setae 1-1; mostly from Australa- equator in the Central PaciÞc Ocean. Brennan and sian/PaciÞc localities (thus far) ...... 4 3. (2.) Total hysterosomal setal count (dorsal ϩ Amerson (1971) did not assign this chigger to a sub- Ͼ genus of Toritrombicula Sasa et al., which at the time ventral) 200; from west of Baja Cali- comprised Toritrombicula (sensu stricto), Cotrom- fornia Peninsula (thus far) ...... bidium Vercammen-Grandjean, and Whartonacarus ...... W. nativitatis (sensu stricto) ϭ Ͻ Vercammen-Grandjean (Nadchatram 1967, Vercam- Total hysterosomal setal count / 150; men-Grandjean 1968). Nor did Brennan and Amerson from east of Baja California Peninsula . . ϭ acknowledge this Vercammen-Grandjean subgeneric ... W. nativitatis ( W. thompsoni [sensu classiÞcation, although they did cite NadchatramÕs Brennan 1953]) work. Furthermore, they described a total of three 4. (2.) Sternal setae 2-2; branches on scutal and new Toritrombicula species in this article and con- body setae short and somewhat ap- trasted each of them with other known congeners. pressed, or less prominent, particularly Perhaps in passive recognition of the similarities of T. basally ...... W. anous (sensu lato) oceanica to species then attributable to the subgenus Sternal setae 2-4; branches longer, more Whartonacarus, Brennan and Amerson chose to com- abundant, and prominent on scutal and pare T. oceanica with W. nativitatis and W. dupliseta. body setae ...... 5 The characters they chose to distinguish between the 5. (4.) Palpgenual seta branched . . . W. oceanica three species are useful only at the species level, Palpgenual seta nude ...... 6 with the possible exception of the length of the palpal 6. (5.) Total hysterosomal setal count (dorsal ϩ tarsala. This structure is always described as very long ventral) Ͼ 150...... in all other Whartonacarus spp., but an actual length ..... W. shiraii (sensu Sasa et al. 1952) (39) is cited only for W. dupliseta (Loomis 1966) and Total hysterosomal setal count Ͻ100; from here for W. floridensis (30); the palpal tarsala is shorter only Sonora, Mexico (thus far) ...... (20) on T. oceanica but still described as “elongate” ...... W. shiraii (sensu Loomis 1966) November 2009 MERTINS ET AL.: W. floridensis SP. NOV., WITH A GENERIC REVIEW 1267

7. (1.) With four genualae I, 4Ð5 genualae II, 6Ð8 specimens and use of facilities. Ken Holscher read and use- genualaeIII;coxaIIIusuallybisetate;palp- fully commented on a draft of the manuscript. Primary fund- genual seta nude ...... W. dupliseta ing for this project was provided through Cooperative Agree- With three genualae I, two genualae II, two ment 0591130808CA, U.S. Department of Agriculture, genualae III; coxa III unisetate: palp- Animal and Plant Health Inspection Service, Veterinary Ser- genual seta sparsely branched ...... vices. Additional funds were provided through sponsorship from the Þsh and wildlife agencies of Alabama, Arkansas, ...... W. floridensis Florida, Georgia, Kansas, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Puerto Rico, South Significance of Whartonacarus in Florida. Our cur- Carolina, Tennessee, Virginia, and West Virginia; through the rent efforts to survey the ectoparasites on a variety of Federal Aid to Wildlife Restoration Act (50 Stat. 917) and vertebrate hosts in the southeastern continental Grant Agreement 06ERAG0005, Biological Resources Divi- United States and Caribbean island territories are mo- sion, U.S. Geological Survey, U.S. Department of the Interior; tivated by concerns for the introduction of potentially and through Cooperative Agreement 0696130032CA, U.S. invasive ticks and other livestock arthropods. One Department of Agriculture, Animal and Plant Health Inspec- speciÞc concern is the presence of A. variegatum and tion Service, Veterinary Services. E. ruminantium, the tick-borne agent of ruminant heartwater, on several Caribbean islands (Barre et al. 1987, Camus and Barre 1995, Pegram et al. 2004), and References Cited the status of cattle egrets as A. variegatum hosts and vectors (Corn et al. 1993). Barre, N., G. Uilenberg, P. C. Morel, and E. Camus. 1987. Danger of introducing heartwater onto the American Although the typical hosts for Whartonacarus chig- mainland: potential role of indigenous and exotic Ambly- gers are charadriiform water birds, unusual hosts have omma ticks. Onderstepoort J. Vet. Res. 54: 405Ð417. been documented, now including the cattle egret. Brennan, J. M. 1953. A note on the chiggers of Jamaica Cattle egrets are not ordinary wading water birds; they (Acarina: Trombiculidae). J. Parasitol. 39: 292Ð295. typically feed away from water and are the most ter- Brennan, J. M. 1966. New records of chiggers (Acarina: restrial of all ardeid birds (Martõ´nez-Vilalta and Motis Trombiculidae) from Baja California and islands of the 1992). Furthermore, they visit freshwater habitats Gulf of California. J. Parasitol. 52: 772Ð775. more frequently than marine habitats, though they are Brennan, J. M. 1967. New records of chiggers from the West found on most Caribbean islands (Corn et al. 1993). Indies. Studies on the Fauna of Curac¸ao and other Ca- Because of their habits, they evidently spend rela- ribbean Islands, No. 95. 24: 146Ð156. Brennan, J. M., and A. B. Amerson. 1971. Six new species tively little time in habitats where many charadriiform and additional records of chiggers from the Central Pa- birds are exposed to Whartonacarus infestations. In- ciÞc (Acarina: Trombiculidae). J. Parasitol. 57: 1311Ð1317. stead, their behaviors, particularly their predilection Brennan, J. M., and M. L. Goff. 1977. Keys to the genera of for foraging among cattle, make cattle egrets more chiggers of the Western Hemisphere (Acarina: Trombic- likely candidate hosts for A. variegatum. The two pre- ulidae). J. Parasitol. 63: 554Ð566. viously known Whartonacarus collections from the Brennan, J. M., and E. K. Jones. 1959. Keys to the chiggers Caribbean Basin, on Jamaica (Brennan 1953) and of North America with synonymic notes and descriptions Trinidad (Brennan 1967), came from sites bracket- of two new genera (Acarina: Trombiculidae). Ann. En- ingÑwest and southeast ofÑthe islands infested by A. tomol. Soc. Am. 52: 7Ð16. Camus, E., and N. Barre. 1995. Vector situation of tick- variegatum, but we do not know if these chiggers borne diseases in the Caribbean islands. Vet. Parasitol. 57: occur on the intervening or other Caribbean islands. 167Ð176. In addition, because this is the Þrst report of W. flori- Corn, J. L., N. Barre, B. Tiebot, T. E. Creekmore, G. I. Garris, densis, we do not know where it breeds, nor do we and V. F. Nettles. 1993. Potential role of cattle egrets, know where our egret became infested by its chiggers. Bubulcus ibis (Ciconiiformes: Ardeidae), in the dissem- The infestation may have been local in the Florida ination of Amblyomma variegatum (Acari: ) in Keys, or may have occurred elsewhere, such as on the eastern Caribbean. J. Med. Entomol. 30: 1029Ð1037. another Caribbean island. If it is a local infestation, this Domrow, R. 1966. Some mite parasites of Australian birds. report presents a new species from an unusual host for Proc. Linn. Soc. New So. Wales 90: 190Ð217. this genus of mites, and a Þrst report of this genus of Domrow, R. 1978. New records and species of chiggers from Australasia (Acari: Trombiculidae). J. Aust. Ento- mites in the United States. However, if we assume that mol. Soc. 17: 75Ð90. the infestation occurred outside of the Keys, it may be Domrow, R., and L. N. Lester. 1985. Chiggers of Australia symbolic of the potential for movement of ectopara- (Acari: Trombiculidae): an annotated checklist, keys and sites from the Caribbean into Florida, and it would bibliography. Aust. J. Zool. Suppl. Ser. 114: 1Ð111. provide further indirect evidence of the potential for Goff, M. L. 1989. Catalog of types in the National Chigger speciÞc avian transport of A. variegatum from the Collection of the U.S. National Museum of Natural His- Caribbean into Florida. tory, Smithsonian Institution (Acari: Trombiculidae). Bull. Soc. Vector Ecol. 14: 95Ð134. Goff, M. L., R. B. Loomis, W. C. Welbourn, and W. J. Wrenn. Acknowledgments 1982. A glossary of chigger terminology (Acari: Trom- biculidae). J. Med. Entomol. 19: 221Ð238. We thank Larry Seal and Jeff Alfred for technical assis- Hoffmann, A. 1950. Contribuciones al conocimiento de los tance in the Þeld and laboratory, respectively, and our thanks trombicu´ lidos mexicanos. 2a. parte. Ciencia (Mex.). 10: go to Wildlife Rescue of the Florida Keys for access to 148Ð153. 1268 JOURNAL OF MEDICAL ENTOMOLOGY Vol. 46, no. 6

Hoffmann, A. 1965. Contribuciones al conocimiento de los Pegram, R., L. Indar, C. Eddi, and J. George. 2004. The trombicu´ lidos mexicanos (Acarina: Trombiculidae). 11a. Caribbean Amblyomma Program: some ecologic factors parte. Folia Entomol. Mex. 9: 3Ð18. affecting its success. Ann. N.Y. Acad. Sci. 1026: 302Ð311. Hoffmann, A. 1990. Los trombicu´ lidos de Me´xico (Acarina: Reeder, W. G., and K. S. Norris. 1954. Distribution, type Trombiculidae). Parte taxono´mica. Univ. Nac. Autono´m. locality, and habits of the Þsh-eating bat, Pizonyx vivesi. Me´x., Inst. Biol. Publ. Espec. 2. J. Mammal. 35: 81Ð87. Hoffmann, A. 1993. Las coleccciones de artropodos de A. Sasa, M., and E. W. Jameson, Jr. 1954. The Trombiculidae of Hoffmann. Univ. Nac. Autono´m. Me´x., Cuad. Inst. Biol. 19. Japan. Proc. Calif. Acad. Sci. (4th Ser.) 28: 247 Ð 321. Keirans, J. E., and L. A. Durden. 2001. Invasion: exotic ticks Sasa, M., R. Kano, and T. Ogata. 1952. Studies on tsutsuga- (Acari: , Ixodidae) imported into the United mushi. 28. On the trombiculid mites parasitic on birds States. A review and new records. J. Med. Entomol. 38: collected in the suburbs of Tokyo. Tokyo Iji Shinshi 850Ð861. (Tokyo Med. J.). 69: 557Ð559. Loomis, R. B. 1966. A new species and new records of the Vercammen-Grandjean, P. H. 1968. The chigger mites of genus Toritrombicula (Acarina, Trombiculidae) from the Far East (Acarina: Trombiculidae & Leeuwenhoeki- idae): an illustrated key and a synopsis; some new tribes, birds of Sonora, Mexico. J. Parasitol. 52: 768Ð771. genera and subgenera. U.S. Army Med. Res. Dev. Com- Martınez-Vilalta, A., and A. Motis. 1992. Family Ardeidae ´ mand, Washington, DC. (herons), pp. 376Ð429. In J. del Hoyo, A. Elliott, and J. Watanabe, T. 1991. Changes in the number of migrating Sargatal [eds.], Handbook of the birds of the world, vol. PaciÞc golden plovers, Pluvialis dominica, at Okubo rice 1. Ostrich to ducks. Lynx Edicions, Barcelona, Spain. Þeld, central Japan. Strix 10: 107Ð114. McLellan, M. E. 1927. Pizonyx vivesi on Isla Partida, Gulf of Wharton, G. W. 1945. Two new species of Acariscus: A. California. J. Mammal. 8: 243. pluvius and A. anous (Acarinida: Trombiculidae). J. Para- Nadchatram, M. 1967. Notes on the genus Toritrombicula sitol. 31: 401Ð405. (Sasa et al.) with designation of neotype, description of Wharton, G. W. 1946. Observations on Ascho¨ngastia indica nymph and redescription of larva of Tori. densipiliata (Hirst 1915) (Acarinida: Trombiculidae). Ecol. Monogr. (Walch), and descriptions of two new species from 16: 151Ð184. Southeast Asia (Acarina: Trombiculidae). J. Med. Ento- Wiersma, T., and P. Wiersma. 1996. Family Charadriidae mol. 4: 401Ð415. (plovers), pp. 384Ð442. In J. del Hoyo, A. Elliott, and J. Nadchatram, M., and A. L. Dohany. 1974. A pictorial key to Sargatal [eds.], Handbook of the birds of the world, vol. the subfamilies, genera and subgenera of Southeast Asian 3. Hoatzin to auks. Lynx Edicions, Barcelona, Spain. chiggers (Acari, , Trombiculidae). Bull. Inst. Med. Res. Malays. 16: 1Ð67. Received 4 March 2009; accepted 27 July 2009.