Macrocheles seraphim Niogret & Nicot

Niogret, Jerome, Nicot, Antoine, Stordeur, Eric De & Bertrand, Michel, 2007, Combination of morphological characters and ITS­sequence to characterize a new species of Macrocheles (Acari: Macrochelidae), Zootaxa 1386, pp. 19-29 : 22-24

Macrocheles seraphim Niogret & Nicot , sp. nov.

Material examined. Holotype female, Trucy l’Orgueilleux, France, 47°45'N, 3°41'E, clay soil, pastured meadow, continental climate, elevation 160 m, April 2006, on Geotrupes mutator . Paratypes, 6 females and 1 male, same data as holotype; deposited in collection of the Muséum National d’Histoire Naturelle de Paris ( France) ( MNHN Ac1105, Ac1106, Ac 1107 in respect); 5 paratype females in the Institut royal des Sciences naturelles de Belgique (Bruxelles, Belgium) (No 30.653). Other paratype specimens (15 individuals) are in the collections of the Laboratoire de Zoogéographie, Montpellier ( France).

Female. Yellowish­brown species, medium size.

Dorsal shield (figure 1): similar in shape to M. glaber , longer than wide with distinct ornamentation, length 805.6 ± 6.5 µm, width 439.7 ± 6.9 µm between setae r3 (n = 10 individuals), clearly demarcated by the procurved line, reticular pattern underlined by punctures around the margins of rather large but irregular pentagonal or hexagonal cells, with irregular separation lines. Shield with 28 pairs of setae, with j1 directed forward, pilose in the distal half (figure 3a), z1 smooth, reduced in length, z6 longer than j6. Except for the short and bi­serrate setae J5, the median setae are simple (j5, j6, z5, z6, J2), others are distally irregular (i.e. j2, s5, Z1, Z2) (figure 3b) or pilose (i.e. s2, r2, S5, Z4, Z5,) (figure 3a) and distally pilose (i.e. j3, j4, z2, z4, s4, s6, r4, S1, S2, S4) (figure 3c).

Ventral shields (figure 2): Tritosternum and peritremes normal for genus. Sternal shield rather large (length 189.5 ± 2.4 µm, width at level of coxae II: 156.2 ± 3.1 µm) (n = 8 individuals) with the usual 3 pairs of smooth setae and 2 pairs of pores. Median transverse line procurved, discrete and marked by a row of small punctures, the two oblique anterior lines joined anterioly, angular and arched lines partially hidden in the anterior half by the reticular ornamentation; punctuate zone anterior to coxae II extending from oblique anterior line. Posterior part of sternal shield with irregular punctate pattern, mostly large medially, extended backward behind the midlevel of coxae III. Metasternal plates close to the sternal shield, not extended behind the posterior edge of coxae III. Epigynial shield with a pair of long setae, broader than long (110–112 µm long, 145– 166 µm maximum width). Epigynial shield with sclerotization attenuated anteriorly, sclerotized lines forming arched pattern, marked by punctures, and a median zone with sub­polygonal pattern (figure 2). Ventri­anal shield as wide as long (ca. 260 µm long), with 6 main transverse procurved lines, longitudinal ornamentation masked, with the polygons marked by punctures and arranged as irregularly defined overlapping tiles, with 3 pairs of pre­anal setae and three para­anal setae; cribrum present. Metapodal sclerites elongate. The postcoxal pore is visible, included in the podal shield.

Gnathosoma : similar to that of M. glaber group species. Chelicerae robust (figure 4). Fixed digit with well developed median tooth pyramidal in shape and a terminal hook, pilus dentilis straight, movable digit with four teeth. Hypostomal groove with five transverse rows of denticles. Arthrodial brush reaching the median level of movable digit. Palpi as in M. glaber group species. Epistome (figure 10) glaber ­like in shape with smooth lateral lobes, central branch pilose.

Sacculus foeminus (figure 5): sacculus wide, elongate (45 µm width), tubuli opening into spherical lateral vesicles that join a thickened median section which feeds into the sperm duct, corniculi long (ca 50 µm).

Legs: chaetotaxy normal for genus, setae simple or lightly pilose distally, except for the tibial posteroventral and distal basitarsal setae on leg IV, and a ventral seta on genu I. Tarsal setae thin and long.

Male. Dorsal shield (figure 6): elongate (485 µm long, 285 µm wide) with rough ornamental pattern, reticulation weakened laterally, irregularly sclerotized laterally, with 28 pairs of setae, j1 long and smooth, distally close together; r2, z4, Z5 and J5 pilose.

Ventral shields: sterno­genital, ventri­anal, endopodal, metapodal and metasternal shields all fused into a holoventral shield; sterno­genital shield with 5 pairs of setae and 3 pairs of pores; length of the shield 395 µm, width at level of coxae II: 90 µm (n = 1). Ventri­anal shield longer than wide, with 3 pairs of pre­anal setae, a pair of para­anal setae and a post­anal seta, all setae simple. Surface ornamentation lacking, only weakly punctuate, stronger at lateral margins. Cribrum present, bordering posterior end of shield. Metapodal sclerites long, with characteristic shape. Pore visible on podal sclerite behind coxa IV.

Gnathosoma well sclerotized. Epistome as in female, M. glaber ­like. Chelicerae (figure 7) with robust digits, weakly dentate, pilus dentilis straight; dorsal seta conspicuous; movable digit with three small teeth, arthrodial brush reaching only 1/3 length of the movable digit; spermatodactyl with large basal bulb and distally blunt, elbowed in the proximal third, strongly recurved backward, distally attenuated.

Legs: tarsus I without ambulacrum and claw; tarsi II–IV with developed ambulacra and claws; legs with a large spur on femur II bearing strong simple anterior seta, genu II with setigerous tubercle. Femur IV with a double spur bearing a pilose seta and a small, non setose tubercle. Dorsal and ventral setae pilose or simple (figures 8–9).

Protonymph (figures 11 & 13). Length of idiosoma: 413 µm; width at level of r3: 207 µm (n = 1). Anterior shield with distally pilose setae z4, j6, s5, j4, other setae simple. Opisthonotal shield reduced, weakly delimited and with distally pilose setae S4, S5, Z4; concave posterior part of the shield delimited anteriorly by a curved line posterior to insertions of J4. Sterno­ventral shield rather soft, poorly sclerotized, with three pairs of setae and two pairs of pores. Anal shield distinct, with opisthogastric setae. Gnathosoma similar to deutonymph, but less developed. Palpal setation deficient, with a crown of only eight terminal setae, but the larger sensory setae of later stages, i.e. one large, hollow and curved, and the bent and hollow seta, are present. Tritosternal base short, with relatively long laciniae, epistome similar to the adult. Genu I with 6 setae.

Deutonymph (figure 12). Length of idiosoma: 546.5 ± 16.3 µm; width at level of setae r3: 283 ± 8.5 µm (n = 2). Dorsal shield with 28 pairs of setae, weakly ornamented and incompletely fused, with opisthonotal portion marked posteriorly by depressed zone, punctate, delimited anteriorly by an arched line that isolates setae J5. Dorsal setae pilose (i.e. j1, j4, z4, r3, Z3, Z4 S4, S5), J5 short and serrate, other dorsal setae smooth; vertical setae j1 widely separated. Tritosternum well developed, with a pair of pilose laciniae. Sterno­ventral shield with 4 pairs of simple setae and 3 pairs of pores. Four pairs of simple setae located between sterno­ventral and anal shields; anal shield longer than wide; with a pair of simple para­anal setae and a shorter post­anal seta.

Etymology. M. seraphim is dedicated to Mr Seraphin Dhotel. Seraphim (Latin etym., from Hebrew) are Biblical creatures similar to angels but they are able to hide and to conceal their presence (Dead Sea Scrolls, "Michael's words" (4Q529)).