Macrocheles kaiju, Knee, Wayne, 2017

Knee, Wayne, 2017, New MacrochelePratums species (Acari, Mesostigmata, Macrochelidae) associated with burying beetles (Silphidae, Nicrophorus) in North America, ZooKeys 721, pp. 1-32 : 11-16

Macrocheles kaiju sp. n. Figs 9, 10, 11, 12, 13C

Material examined.

Type material. Holotype: female (CNC829453) on Nicrophorus carolinus (N333, male) collected Highlands Co. Lake Placid, Florida, USA (27.181, -81.352), 10.iii.2009, coll: W. Knee & S. Peck.

Paratypes (28): 14 females (CNC CNC829454-829467) with the same collection information as the holotype; 13 females (CNC829468-829480) on N. carolinus (N334, female), Highlands Co. Lake Placid, Florida, USA (27.181, -81.352), 10.iii.2009, coll: W. Knee & S. Peck; female (CNC829481) on N. carolinus (N081), Highlands Co. Lake Placid, Florida, USA (27.181, -81.352), 10.iii.2009, coll: W. Knee & S. Peck.

Other material. 134 mites examined from Florida and Nebraska on N. carolinus (Table 1).

Diagnosis female.

Dorsal setae smooth and spinose, except r3, r4, s6, z6, S1-S5, Z1-Z5, J2 barbed distally, J5 barbed, marginal and submarginal setae barbed distally. Seta j1 smooth, spike, tapered distally with rounded tip, slightly longer than z1. Seta J5 much shorter than Z5. Dorsal hexagonal setae as long as marginal and submarginal setae. Dorsal shield smooth medially with faint reticulations near shield margins, shield tapers from humeral region to posterior margin. Dorsal shield without well-defined procurved line, sigillary rami absent. Setae on sternal, genital and ventrianal shields, and ZV1 smooth and spinose, other ventral setae in soft integument barbed distally. Sternal shield wider than long, punctures small, posterior margin slightly concave. Well defined l.m.t. and l.o.a.; l.o.a. contacts l.m.t. Well defined l.arc. contacts l.o.a., l.ang. and l.o.p. well defined laterally but faint medially. Well defined a.p.l., but a.p.p. not well defined. Ventrianal shield longer than wide (ratio 1.5), pon longer than pan, pon slightly spatulate. Arthrodial brush nearly as long as movable digit. Genu IV with six setae.

Description female.

Dorsal idiosoma (Fig. 9). Dorsal shield 736 (647-812) long and 484 (421-547) (n=8) wide (level with r3), with 28 pairs of setae. Dorsal setae smooth and spinose, except r3, r4, s6, z6, S1-S5, Z1-Z5, J2 barbed distally, J5 barbed, marginal and submarginal setae barbed distally. Seta J5 22 (19-24) less than half as long as Z5 75 (65-83). Seta j1 29 (25-34) smooth, spike, tapered distally with rounded tip, slightly longer than z1 24 (20-32). Dorsal hexagonal setae 61 (50-71) smooth and spinose, as long as distally barbed marginal and submarginal setae (61). Dorsal shield smooth medially with faint reticulations near shield margins, shield tapers from humeral region to posterior margin. Dorsal shield without well-defined procurved line, sigillary rami absent. Dorsal shield fused to peritrematal shield near r3 and anterior margin of shield wraps around onto ventral surface, j1 on slight projection and typically on the venter, and z1 occasionally expressed ventrally. Shield with 22 pairs of pore-like structures, of which six are secretory glands and 16 are non-secretory poroids.

Ventral idiosoma (Figs 10, 13C). Sternal shield wider than long, medial length 155 (145-163), maximum width 260 (224-288) level with a.p.l., and minimum width 115 (103-121) posterior of st1. Sternal shield punctures small, posterior margin slightly concave. Setae st1-3 75 (61-92) simple and spinose, and two pairs of lyrifissures (iv1, iv2) on sternal shield. Pear-shaped metasternal shields well separated from sternal shield margin bearing lyrifissure iv3 anteriorly and spinose seta st4 80 (73-89) posteriorly. Well defined l.m.t. and l.o.a.; l.o.a. contacts l.m.t. Well defined l.arc. contacts l.o.a., l.ang. and l.o.p. well defined laterally but faint medially. Well defined a.p.l., a.p.p. not well defined. Genital shield length 196 (172-226), width 123 (109-141) level with st5. Genital shield truncate posteriorly and hyaline margin rounded anteriorly, spinose seta st5 70 (65-74) on shield, pair of lyrifissures iv5 off shield near posterior margin. Transverse line on genital shield well defined, and without punctures. Peritrematal shield narrow, fused to dorsal shield near r3, peritreme extends beyond posterior margin of coxa I, two poroids (id3, id7) and one gland (gd3) on the shield. Ventrianal shield longer than wide (ratio 1.5); length 230 (202-250), width 149 (135-160) anterior to JV2. Ventrianal shield bearing several faint transverse lines, three pairs of simple spinose preanal setae JV1-JV3 65 (64-75), spinose pan 37 (26-43) shorter than slightly spatulate pon 47 (40-54), narrow cribrum and a pair of glands (gv3) on shield margin posterior of the anal opening. Seta ZV1 55 (48-60) is simple, all other ventral opisthosomal setae in soft integument barbed distally, ZV1 and ZV2 67 (58-75) as long or nearly as long as Jv setae. Two pairs of glands (gv2 and unknown paired-pore) and four pairs of poroids (ivo, ivp) in opisthosomal soft integument.

Gnathosoma (Fig. 11). Basis capitulum medial length excluding internal malae 159 (152-169), width 158 (153-170) posterior to pc. Subcapitular setae simple: h1 66 (61-70), h2 19 (17-21), h3 92 (85-98), and pc 25 (24-28). Palp chaetotaxy normal for genus (2 –5–6–14– 15), palp apotele three-tined, al setae on trochanter, femur and genu slightly spatulate. Corniculi pointed, maximum length 50 (45-60), internal malae thick and bristled. Epistome tripartite with bifid central element bearing small fringe medially, lateral elements broad and flag-like distally with irregular barbs, epistomatic margin finely serrate. Subcapitulum with seven rows, six of which have deutosternal denticles; the anterior most row with few (four) denticles laterally, and the second anterior most row with paired ridges without any denticles. Chelicerae robust, length of second cheliceral segment including fixed digit 184 (173-198), and movable digit 64 (60-67). Fixed digit bidentate with one large and one small tooth, movable digit with a bidentate tooth flanked by a small tooth distally. Pilus dentilis and dorsal seta on fixed digit simple spike, fixed digit with lyrifissure on each paraxial and antiaxial faces. Movable digit with narrow fringed arthrodial corona, and plumose arthrodial brush (57) almost as long as movable digit.

Legs (Fig. 12). Excluding ambulacra, lengths of leg I 512 (488-527), leg II 576 (525-622), leg III 482 (436-528), and leg IV 690 (628-737). Ambulacra only present on legs II–IV, claws II–IV well developed. Slight ridge on femur II anterolateral, not always easily visible. Slight ridge on femur IV dorsal, genu and tibia IV posterolateral. Pair of glands (gc) on coxa I. Setation of legs I–IV normal for Macrochelidae : coxae 2 –2–2– 1; trochanters 5 –5–5– 5; femora I (2 –3/1,2/3– 2), II (2 –3/1,2/2– 1), III (1 –2/0,1/1– 1), IV (1 –2/1,1/0– 1); genua I, II (2 –3/1,2/1– 2), III (1 –2/1,2/0– 1), IV (1 –2/1,2/0– 0); tibiae I (2 –3/2,2/1– 2), II (2 –2/1,2/1– 2), III, IV (1 –1/1,2/1– 1); tarsus I 20 setae plus numerous tapered setae dorsoterminally, tarsi II–IV 18. Setae on leg I are setiform and simple, setae on legs II–IV variable, most are setiform, others are variously modified. Femur II ad1, genu II ad3, and trochanter III with a prominent spike setae with flattened forked tip with two to four tines that can appear as a single tapered point viewed laterally. Tarsus II with 13 thick conical spike setae with either a rounded or filamentous tip; filamentous tip fragile and easily broken. Tarsi III, IV with four distal spike setae with wide base and flexible filamentous tip, tip easily broken. Long setae with small spatulate tip with or without barbs on femur IV ad1, ad2, pd1, genu IV al, ad1, pd1, pd2, tibia IV al, pl, and three on tarsus IV. Setae with small spatulate tip appear pointed when viewed laterally.

Male and immatures

. Unknown.

Etymology.

Kaiju, 怪獣, from Japanese means strange beast, and refers to giant monsters such as Godzilla or Mothra. Female M. kaiju sp. n. is relatively unique morphologically when compared to other Macrocheles species associated with beetles, it is relatively large, has a unique dorsal shield shape, and bears numerous setae with distinct forms.

Remarks.

Female M. kaiju sp. n. is different from that of any other described Macrocheles species; however, it does fit the Macrocheles generic description (see Hy att and Emberson 1988). Female M. kaiju sp. n. has two character states that are irregular for Macrocheles but somewhat similar to Holostaspella ( Macrochelidae ) species: the anterior margin of the dorsal shield wraps around onto the ventral surface such that j1 is on a slight projection on the venter; and a slight ridge is present on femur II. Holostaspella species are characterised in part by females having a spur on femur II, and j1 being on a tuberculate anterior extension of the dorsal shield but not wrapped around onto the venter. Macrocheles kaiju sp. n. differs from that of Holostaspella species in having weak ornamentation on the dorsal shield, its lateral regions without a series of depressions; j1 is smooth and not pectinate, j1 is on a slight projection and not a prominent tuberculate extension; sternal shield weakly ornamented and without strong median ridge; and metasternal shields small and always free of endopodal shields.