Neopterygosoma, Fajfer, 2019

Fajfer, Monika, 2019, Systematics of reptile-associated scale mites of the genus Pterygosoma (Acariformes: Pterygosomatidae) derived from external morphology, Zootaxa 4603 (3), pp. 401-440 : 422-423

Genus Neopterygosoma n. gen.

Type species: Pterygosoma chilensis Fajfer and González-Acuña, 2013 .

Description. FEMALE. Gnathosoma . Movable cheliceral digit without basal spur. Palps with setation (femurtarsus): 1–1–3–5, palp femoral seta dF longer than palp genual seta dG, palpal tibia with 3 long simple setae and stout claw, palpal tarsus with 5 setae (ba, bp, lp, va, ul’) and solenidion ω. Subcapitulum with 1 pair of setae n. Hypostome with smooth rounded apex. Fixed cheliceral digit reduced to rounded structure. Peritremes situated dorsally. Idiosoma. Body at least 1.2 times wider than long. Dorsum with numerous ornamented setae. Anteromedial part of idiosoma with plumose short setae, maximum 35 long, grouped in common cluster (anterior-mid cluster); numerous plumose setae, about 150–230 pairs, situated laterally and postero-laterally to this cluster. Postero-medial part of idiosoma with multiplied dorso-median setae or two pairs of dorso-median setae (dm). Posterior part of idiosoma with peripheral setae that integrate imperceptibly on dorsal and ventral sides of idiosoma. Eyes present. Venter. Posterior part with several setae vm located anterior to or laterally to genital area. Postero-lateral parts with 9–40 setae, uniform or variable in length. Genital series represented by 1 pair of finepointed setae g1 situated on ventral side. Pseudanal series represented by 3–5 pairs of setae ps. Legs. Coxal setation: 1a, 1b, 2b, 3a, 3b, 3c, 3d arranged in formula 2–1–4–0; all setae situated on coxal fields, except for 3a located on intercoxal area, coxal setae: 1a, 1b, 2b, 3b and 3c filiform, 3d slightly serrate, setae of trochanters I–IV (1–1–1–1), femora I–IV (5–5[4]–3–3[2]), genua I–IV (5[4]–5[4]–3–3[2]), tibiae I–IV(5–5[4]–5–5). All setae on each podomere plumose, dorsal setae thicker than ventral ones. Setation of tarsi I–IV: I 14 setae (ft, tc’, tc”, p’, p”, a’, a”, it’, it”, u’, u”, vs’, vs”, pl’) and solenidion ω1; II 10 setae (tc’, tc”, p’, p”, a’, a”, u’, u”, vs’, vs”) and ω1; III and IV with 10 setae each (tc’, tc, ” p’, p”, a’, a”, u’, u”, vs’, vs”). Setae pl’ slightly serrate. All setae a’ and a” smooth, u’ and u” pectinate, vs’ and vs” bipectinate.

MALE. Unknown.

Differential diagnosis. Neopterygosoma n. gen. is most similar to Pterygosoma Peters, 1849 , by sharing a similar arrangement of the antero-lateral setae, the dorsal setae increase in length from the anterior to the posterior part of the idiosomal dorsum, and setae ft on tarsi I are at least twice as long as solenidion ω1.

Females of Neopterygosoma differ from those of Pterygosoma by the following character states: movable cheliceral digit without basal spur; setae ul’ and solenidion of palpal tarsus present; cluster of anterior mid-dorsal setae is present, with a large number of setae (>200) on lateral and posterior parts of dorsum and lateral parts of venter; ventro-median setae vm are multiplied; setae 3a are situated outside coxal plates; coxal setae 3c and 3d present; leg setae tc”TaII–IV, vs”TaII–IV, l’TiII–IV, l“TiII–IV, l”GI, dGII–IV, l’GII, l”GII, lGIII, l”FI–III, vFI–III and lFIV present. In contrast, females of Pterygosoma have: movable cheliceral digit with basal spur; setae ul’ and solenidion of palpal tarsus absent; cluster of anterior mid-dorsal setae absent, a smaller number of setae (<200) on lateral and posterior parts of dorsum and lateral parts of venter; three pairs of ventro-median setae vm1–vm3; setae 3a situated on coxal plates; coxal setae 3c and 3d absent; setae tc”TaII–IV, vs”TaII–IV, l’TiII–IV, l“TiII–IV, l”GI, dGII–IV, l’GII, l”GII, lGIII, l”FI–III, vFI–III and lFIV absent.

Distribution and host range. This genus is associated with tree lizards of the genus Liolaemus (Sauria: Liolaemidae ) from South America [ Chile and Argentina].

Habitat. Under all dorsal, lateral and ventral scales of the head, belly and tail.

Species included. N. chilensis ( Fajfer & González-Acuña, 2013) , N. cyanogasteri ( Fajfer & González-Acuña, 2013), N. formosus ( Fajfer & González-Acuña, 2013) , N. levissima ( Fajfer & González-Acuña, 2013) , N. ligare ( Fajfer & González-Acuña, 2013) , N. ovata ( Fajfer & González-Acuña, 2013) and N. patagonica ( Dittmar de la Cruz, Morando & Avila, 2004) .

Remarks. According to the phylogenetic analysis the genus Geckobia is a sister taxon to the newly established genus Neopterygosoma . However, it was impossible to find any common features at the generic level between all known Geckobia species and members of the genus Neopterygosoma . Therefore, in the differential diagnosis of this genus I compared it with the genus Pterygosoma in which the species of Neopterygosoma were included previously based on their general resemblance ( Fajfer & Gonzalez-Acuña 2013).

In our analysis, the genus Geckobia was rendered paraphyletic. The results are partly consistent with the latest studies of diversity and taxonomy of the genus Geckobia made by Bochkov & Mironov (2000). The authors suggested that subsequent studies will allow splitting the genus into several groups or even genera corresponding to certain taxa of geckos or living in certain geographical regions. For these reasons, representatives of this genus need to be included in future phylogenetic studies to better unravel the taxonomic structure and content of this diverse pterygosomatid group.

It is also worth noting that based on the phylogenetic analysis, Geckobia nitidus Fajfer, 2015 , which is a member of the nitidus group together with G. zappalarensis Fajfer, 2015 ( Fajfer 2015) , is a sister taxon to all species of the genus Neopterygosoma .

In representatives of the nitidus group and Neopterygosoma the chaetotaxy of the gnathosoma and legs I–IV is the same. However, species of the nitidus group share a unique combination of character states that clearly separate them from the genus Neopterygosoma , i.e. legs III–IV are directed anteriorly (vs. legs III–IV are directed posteriorly in Neopterygosoma ), antero-median setae are not grouped in a common cluster (vs. the common cluster is present), the genital and anal orifices are clearly separated from each other (vs. the anal and genital orifices are coalesced), coxal setae 2a and 4a are present (vs. setae 2a and 4a are absent), genital setae g2 and pseudanal setae ps6 are present (vs. setae g2 and ps6 are absent).