Acantholaelaps Joharchi & Halliday & Tolstikov & Trach 2019, gen. nov.
Creators: name: Joharchi, Omid
name: Halliday, Bruce
name: Tolstikov, Andrei V.
name: Trach, Viacheslav A.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Mesostigmata
Laelapidae
Acantholaelaps

description: Genus Acantholaelaps gen. nov.
Type species: Acantholaelaps strategus sp. nov.
Description. Female. Laelapidae with an oval-shaped dorsal shield without lateral incisions, bearing 28 pairs of setae (28 pairs in 14 specimens including holotype, 29 pairs in three specimens [S3 on shield] and 30 pairs [s2 & S3 on shield] in three specimens), without Zx setae between the J and Z setae; all dorsal shield setae smooth, pointed and variable in length, marginal setae longest and often appearing wavy in slide-mounted specimens, S5 greatly elongated and wavy in form, at least two-thirds of the body length (Figures 12, 17, 18, 21, 23, 24, 26). Lateral soft skin and opisthogastric area strongly hypertrichous (Figure 25); one pair of caudal setae greatly elongated and wavy in form, at least two-thirds of the body length (Figures 13, 22). Sternal shield reduced in size and longer than wide, its anterior margin often poorly defined, bearing two pairs of long setae, st1 off the shield; genital shield with one pair of setae (Figures 13, 19, 20, 22, 33, 34). Anal shield with para-anal setae longer than unpaired post-anal seta (Figures 13, 34). Hypostome with six rows of minute teeth; hypostomal seta h3 longer than other hypostomal setae. Trochanter of palp bearing two long setae, palp tarsal claw two-tined (Figures 14, 28, 29 & 36). Peritrematal shield broadly enlarged around stigmatic opening (Figure 27), post-stigmatic section not clearly defined (Figure 27). Legs I longer than legs II & III, legs IV longest (Figure 21); greatly elongated macrosetae present on genua and femora I–IV (pd1 on legs I & II and ad1 on III & IV). Tibia III with eight setae (2 1/1 2/1 1) (Figures 37–40). Tarsus II–IV with subterminal blunt spines (al1 and pl1); pre-tarsi II–IV with a pair of stout claws, each claw with a basal spur on its inner margin (Figures 31–32).
Male. As for female except ventral idiosoma with separate sternogenital and anal shields, and an extra irregularly-shaped area of sclerotisation between them (Figures 47–49). Tarsi II and III with strong spine-like setae av1 and av2 (Figures 51–52). Spermatodactyl longer than movable digit, sharply bent upward apically into S-shape, with truncate tip (Figures 46, 50).
Differential diagnosis. The new genus can easily be distinguished from other related members of the family by a combination of morphological attributes, some of which are unique or rarely observed in laelapid mites, such as (1) dorsal seta S5 markedly elongated (2) very long dorsal setae (macrosetae) on femur and genu of legs I-IV (pd1 on legs I & II and ad1 on III & IV) (3) tibia III bears eight setae (2 1/1 2/1 1) (4) tarsus II–IV with subterminal blunt spines (al1 and pl1) (5) claws on pre-tarsi II–IV with a basal spur on their convex surface; (6) peritrematal shield broadly enlarged around stigmatic opening; (7) sternal shield reduced in size and longer than wide and bearing two pairs setae, st1 off the shield; (8) opisthogastric area strongly hypertrichous.
Females of the new genus are similar to Mumulaelaps Clark (in Clark & Hawke, 2012) in having the dorsal shield without lateral incisions, lateral soft skin strongly hypertrichous, sternal shield reduced in size and longer than wide and bearing two pairs setae, st1 off the shield, legs I longer than II and III, elongated setae (macrosetae) on genua and femora I-IV (pd1 on legs I & II and ad1 on III & IV), tibia III bearing eight setae (2 1/1 2/1 1), and tarsus II-IV with subterminal blunt spines (al1 and pl1). The new genus differs from Mumulaelaps by the 28 pairs of dorsal shield setae (15 podonotal, 13 opisthonotal), with j–J and z–Z series complete (vs. 22 pairs (12 podonotal, 10 opisthonotal) and missing many setae from j–J and z–Z series in Mumulaelaps), setae S5 greatly elongated and on dorsal shield (vs not markedly elongated and off the dorsal shield), setae Z4 & Z5 not markedly elongated (vs markedly elongated), opisthogastric area strongly hypertrichous (one pair of caudal setae greatly elongated, at least two-thirds of the body length) (vs. opisthogastric area hypotrichous in Mumulaelaps, lacking very long caudal setae), peritrematal shield broadly enlarged around stigmatic opening (Figure 27) and post-stigmatic section not conspicuous (vs. peritrematal shield normal and post-stigmatic section conspicuous in Mumulaelaps), one elongated seta (ad1) (macroseta) on each genua III–IV, and tibia IV without elongated macrosetae (vs. two elongated setae (ad1, pd1) (macrosetae) on each genua III–IV and ad1 on tibia IV elongated setae (macrosetae) in Mumulaelaps), and pre-tarsi II–IV with a basal spur on the inner surface of each tarsal claw (Figures 31–32). The last character state is otherwise unknown in the free-living Laelapidae, and appears to be autapomorphic for the new genus.
The new genus is also very similar to Coleolaelaps. These two genera both have lightly sclerotised idiosomal shields, sternal shield reduced to leave small triangular endopodal fragments, sternal setae st1 inserted in soft skin anterior to the sternal shield, and greatly elongated setae on the dorsal shield and some leg segments. These appear to be apomorphic character states in both genera. Most species of Coleolaelaps have a posteriorly reduced dorsal shield, which also appears to be apomorphic, but C. abnormalis Costa & Hunter, 1971 has a normal oval-shaped dorsal shield. Coleolaelaps brachysetus Costa & Hunter, 1971 has a posteriorly reduced dorsal shield, but is atypical in lacking greatly elongate setae on the dorsal shield and legs. These may be plesiomorphic character states in two early-derivative members of the genus. Acantholaelaps shares some derived character states with Coleolaelaps, but has a normal oval-shaped dorsal shield similar to that of C. abnormalis. However, Acantholaelaps differs from all species of Coleolaelaps in the presence of thick blunt setae on tarsus II, modified tarsal claws, the relative length of the legs (length of leg I longer than leg III vs. shorter than leg III in Coleolaelaps), and a short post-anal seta. The new genus is compared with other morphologically similar hypoaspidine genera associated with scarab beetles in Table 1. A full analysis of these character states must await the description of more beetle-associated species in genera similar to Coleolaelaps, Mumulaelaps, and Acantholaelaps.
Etymology. The name Acantholaelaps (Latin Acantho, spur) refers to the basal spur on the tarsal claws. Gender masculine.
description: Published as part of Joharchi, Omid, Halliday, Bruce, Tolstikov, Andrei V. & Trach, Viacheslav A., 2019, New records and new species of mites from Cuba, with description of a new genus of Laelapidae (Acari: Mesostigmata), pp. 326-350 in Zootaxa 4612 (3) on pages 329-331, DOI: 10.11646/zootaxa.4612.3.2, http://zenodo.org/record/3235112