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Compluriscutula vetulum (Acari: Ixodida: Ixodidae), A New Genus and Species of Hard from Lower Cretaceous Burmese

Article in Proceedings- Entomological Society of Washington · April 2008

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COMPLURISCUTULA VETULUM (ACARI: IXODIDA: IXODIDAE), A NEW GENUS AND SPECIES OF HARD TICK FROM LOWER CRETACEOUS

GEORGE O. POINAR AND RON BUCKLEY

(GOP) Department of Entomology, Oregon State University, Corvallis, OR 97331, U.S.A. (e-mail: [email protected]); (RB) 9635 Sumter Road, Florence, KY 41042, U.S.A. (e-mail: [email protected])

Abstract.—Compluriscutula vetulum, n. gen., n. sp. (Acari: Ixodida: Ixodidae), is described from Lower Cretaceous Burmese amber. Diagnostic characters include a circular body, thirteen festoons, elongate 4-segmented palpi with the fourth segment distinct and subapical, the absence of eyes and an anal groove, and the presence of 3– 4 uneven rows of 2/2 unequal teeth located on the anterior half of the hypostome. The larger teeth are covered with minute denticles. This is the third genus of hard reported from Burmese amber, showing that a high level of tick diversity existed 100 mya. Key Words: Compluriscutula vetulum, Ixodidae, Burmese amber, Lower Cretaceous

Fossil ticks are rare and currently a mile (1.5 km) SSW of the old Khanja- occur only in amber deposits. Tertiary maw mine site and southwest of Main- hard (Ixodidae) and soft (Argasidae) gkhwan (26u209N, 96u369E). This site is ticks have been described from Baltic newly mined (Doug Cruickshank, per- (Weidner 1964) and Dominican amber sonal communication, December 20, (Lane and Poinar 1986; Poinar 1995; 2006) and has been designated as the Keirans et al. 2002). A larval soft tick ‘‘Noije Bum 2001 Summit Site.’’ Paleon- was described from tological findings from this site assigned amber (Klompen and Gri- its age to the Upper Albian (100 myBP) maldi 2001) and larval hard ticks have of the Lower Cretaceous (Cruickshank been described (Poinar and Brown 2003) and Ko 2003). or reported (Rasnitsyn and Ross 2000; Observations, drawings, and photo- Klompen 2002) in Lower Cretaceous graphs were made with a Nikon SMZ-10 Burmese amber. In this study, we de- stereoscopic microscope and Nikon Op- scribe a new genus and species of hard tiphot microscope (with magnifications tick in Burmese amber. up to 6503). The amber piece containing the tick is rectangular in outline, mea- MATERIALS AND METHODS suring 10 mm in greatest length, 3 mm in The fossil tick was collected from greatest width and 2 mm in greatest lignitic seams in sandstone-limestone depth. The specimen is well preserved, deposits in the Hukawng Valley in although flattened and slightly distorted Myanmar. The mine site was located from the fossilization process. However, on the slope of the Noije Bum hill about the body is sufficiently clear to show

Proceedings of the Entomological Society of Washington went-110-02-16.3d 4/1/08 00:34:36 445 Cust # 07-014 446 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON various setae on both the dorsal and in length; apical corona not observed; ventral surfaces. All measurements are in chelicerae two-segmented, nearly trans- microns unless otherwise specified. parent, slightly longer than hypostome, length 159, apex obscured. Compluriscutula Poinar and Buckley, Legs: Coxae I with no obvious spurs; new genus coxae II with small internal and external Type species: Compluriscutula vetulum spurs; coxae III with large internal and Poinar and Buckley. external spurs; tarsus I tapering distally, Description.—Body subcircular; with length 253, greatest width 32; tarsi II 13 dorsomarginal festoons reaching mar- tapering distally, length 190, greatest ginal groove; anal groove, eyes and width 25; tarsi III uniform, length 184, sensilla sagittiformia not detected; scutum greatest width 32; clear area on dorsum present; palpi long, with four segments, of tarsi I may represent Haller’s organ; the fourth subapical; with 3–4 uneven claws paired, slender, simple, slightly rows of 2/2 unequal teeth located on curved; with distinct pulvillus. anterior half of hypostome; larger teeth Chaetotaxy: Setae detected on dorsal covered with minute denticles. surface include: 2 pairs of scutal setae and 2 pairs of central dorsal setae; setae Compluriscutula vetulum Poinar and detected on ventral surface include: 3 Buckley, new species pairs of posthypostomal setae, 4 pairs of (Figs. 1–5) sternal setae, 2 pairs of preanal setae, 2 pairs of premarginal setae and one pair Description, unengorged larva.—Idio- of anal setae. No typical marginal setae soma: Ornamentation indistinct; body observed; however, on each side of body subcircular; length (excluding capitulum) margin at base of hypostome is a large, 530, greatest width 532; dorsal shield scalelike seta that projects forward. (scutum) with posterior margin convex, Material examined.—Holotype larva 196 in length and 380 in greatest width; in Burmese amber from the Hukawng scapulae rounded; large scalelike seta Valley deposited in the Buckley amber arises from each scapula; marginal collection, Florence, Kentucky. Speci- groove extending around posterior half men available for study by contacting of body (obscured in areas of flattening); RB. thirteen festoons ranging in basal width Type locality.—Amber mine in the from 48 to 70 except for center festoon, Hukawng Valley, southwest of Main- which is 95 in width; anus located 123 gkhwan in the State of Kachin (26u209N, from posterior border. 96u369E), northern Myanmar (Burma). Capitulum: Basis capituli triangular, Etymology.—‘‘Complures’’ is Latin for length from palpal insertion to posterior many and ‘‘scutula’’ is Latin for small margin of basis 35, width 70; palpi plate (referring to the festoons). The cylindrical, with length/greatest width gender is feminine. The specific epithet of four segments as follows; segment 1, ‘‘vetulum’’ is Latin for old and is used as 25/25; segment 2, 95/25; segment 3, 22/ a noun in apposition. 25; segment 4, 13/16; segment 4 subapical Diagnosis.—The most obvious diag- with elongate terminal setae; hypostome nostic character of Compluriscutula vetu- length 133, width at base 35; with 3–4 lum is the presence of 13 festoons. All rows of 2/2 blunt-tipped, unequal teeth known extant and extinct ixodid ticks on the anterior half of the hypostome; have 11 or fewer (Clifford and Anastos large hypostomal teeth covered with 1960; Krantz 1978; Keirans et al. 2002; minute denticles ranging from 2 to 4 Nuttall et al. 1911; Poinar and Brown

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Figs. 1–3. Compluriscutula vetulum in Burmese amber. 1, Dorsal view; bar 5 350 mm. 2, Hypostome with teeth (ventral view); bar 5 38 mm. 3, Festoons on left side of body (dorsal view). Arrows show grooves separating festoons; fleche shows central festoon; bar 5 38 mm.

2003). On the fossil, all festoons are to the remainder. In the fossil, the central separated from the body by grooves festoon is considerably wider than the visible on both dorsal and ventral others, the outer cuticle bordering this surfaces. Another unusual character is festoon is slightly indented and a faint the nature of the central festoon. In crease extends from the indentation extant ticks, there is always an odd towards the marginal line, suggesting number of festoons with equal numbers that earlier lineages might have had 14 extending out from both sides of a festoons. central festoon usually positioned direct- Another diagnostic character of Com- ly beneath the anus (Clifford and Ana- pluriscutula vetulum is unequal hyposto- stos 1960; Krantz 1978). This central mal teeth bearing minute denticles. There festoon is usually smaller or equal in size are only 3–4 rows of teeth positioned on

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Fig. 4. Compluriscutula vetulum in Burmese amber. Dorsal surface (anus from ventral side shown for orientation); bar 5 95 mm. the upper half of the hypostome. Hypos- fication of larval hard ticks, therefore we tomal teeth in the same rows tend to be attempted to record all visible setae on the similar in size in extant ticks bearing fossil. Those observed did not match the scutal plates (however those in the apical setal patterns of the ten genera listed in rows are often larger than those in the Table 1 of Clifford and Anastos (1960). basal rows) and cover most of the Also, the combination of characters on hypostome (Nuttall et al. 1911; Arthur the fossil (the absence of sensilla sagitti- 1957; Clifford and Anastos 1960; Krantz formia and an anal groove plus the 1978). The aforementioned characters, as presence of 3 pairs of posthypostomal well as the absence of palpal claws, setae) is not accomodated in the key to the separate this species from Cornupalpa- genera of larval hard ticks presented by tum burmanicum Poinar and Brown Clifford and Anastos (1960). (2003), the only other described tick The present specimen, together with C. from Burmese amber. burmanicum (Poinar and Brown 2003) and a larval Amblylomma Koch 1844 DISCUSSION (Klompen 2002) shows that tick diversity Clifford and Anastos (1960) empha- at the Burmese amber site was composed sized the use of chaetotaxy in the identi- of at least three generic lineages.

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Fig. 5. Compluriscutula vetulum in Burmese amber. Ventral surface showing configuration of coxae, ventral setae, and anus; bar 5 95 mm.

ACKNOWLEDGMENTS manuscript, Doug Cruickshank for pro- viding information on the site where the Thanks are extended to Jerry Krantz fossil was found, and Roberta Poinar for for reviewing an earlier version of this editorial comments.

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LITERATURE CITED Krantz, G. W. 1978. A Manual of Acarology. Second Edition. Oregon State University Book Arthur, D. R. 1957. The capitulum and feeding Stores, Inc., Corvallis. mechanism of Dermacentor parumapertus Neu- Lane, R. S. and G. O. PoinarJr. 1986. First fossil mann 1901. Parasitology 47: 169–184. tick (Acari: Ixodidae) in New World amber. Clifford, C. M. and G. Anastos. 1960. The use of International Journal of Acarology 12: 75–78. chaetotaxy in the identification of larval ticks Nuttall, G. H. F., C. Warburton, W. F. Cooper, (Acarina: Ixodidae). Journal of Parasitology and L. E. Robinson. 1911. Ticks: A mono- 46: 567–578. graph of the Ixodoidea, Part II. Cambridge Cruickshank, R. D. and K. Ko. 2003. Geology of University Press, Cambridge. an amber locality in the Hukawng Valley, Poinar, G. O., Jr. 1995. First fossil soft ticks, northern Myanmar. Journal of Asian Earth Ornithodoros antiquus n.sp. (Acari: Argasidae) Sciences 21: 441–455. in Dominican amber with evidence of their Keirans, J. E., R. S. Lane, and R. Cauble. 2002. A mammalian host. Experientia 51: 384–387. series of larval Amblyomma species (Acari: Poinar, G. O., Jr. and A. Brown. 2003. A new Ixodidae) from amber deposits in the Domin- genus of hard ticks in Cretaceous Burmese ican Republic. International Journal of Aca- amber (Acari: Ixodida: Ixodidae). Systematic rology 28: 61–66. Parasitology 54: 199–205. Klompen, H. 2002. p. 27. In Grimaldi, D. A., M. S. Rasnitsyn, A. P. and A. J. Ross. 2000. A Engel, and P. C. Nascimbene, eds. Fossilifer- preliminary list of arthropod families present ous Cretaceous Amber from Myanmar in the Burmese amber collection at The (Burma). American Museum Novitates 3361, Natrual History Museum, London. Bulletin 71. of the Natural History Museum London Klompen, H. and D. Grimaldi. 2001. First (Geology) 56: 21–24. Mesozoic record of a parasitiform mite: A Weidner, H. 1964. Eine Zecke, Ixodes succineus sp. larval argasid tick in Cretaceous amber (Acari: n., in baltischen Bernstein. Vero¨ffentlichungen Ixodida: Argasidae). Annals of the Entomo- aus dem U¨ berseemuseum in Bremen 3: logical Society of America 94: 10–15. 143–151.

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