Punkochyzeria minaevi Kolesnikov, Turbanov & Vorontsov, 2025, sp. nov.
Year: 2025
Type: other
Abstract: Punkochyzeria minaevi sp. nov. (Figs. 1–6, 17A–C, 18A–E, Table 2) Diagnosis. Long dorsal setae of two kinds: 1) slender, very densely ciliated or plumose, length of cilia at least twice the width of setal shaft (Fig. 17A–C), density of cilia decreases to base of seta; and 2) slightly shorter, thicker, rigid, spine-like (Fig. 17A, B). Posterior perimeter of opisthosoma with long ciliated or plumose setae (Figs. 1E, I, 5D, 6C). Other dorsal opisthosomal setae moderately short, ciliated or plumose (Fig. 5E). Odontus strong, its base in lateral projection equal to or wider than width of palptarsus (Figs. 4C, D, 18A–E). Palp tarsus extends beyond termination of odontus, shorter than twice the length of odontus (Figs. 3E, F, 4C, D, 18A–E). Dorsal ctenidium of 1–2 spinose setae (Figs. 4C, D, 18A–E). Dorsal integument of opisthosoma reticulated (Fig. 1H). Dorsal surface of opisthosoma without dense setation, with rare setae forming medial longitudinal row, with at least two setae laterad to medial row (Fig. 1E, F). Type material. Holotype PIN-5608/343a, paratype IM-1177a. Occurrence and geological age. Mid-Cretaceous amber, Hukawng Valley, Kachin State, northern Myanmar. Type deposition. PIN 5608 /343a—Borissiak Paleontological Institute, Russian Academy of Sciences; IM-1177a—private collection of Ilya G. Minaev (Ryazan, Russia). Description Holotype (PIN 5608 /343a, ex. IM-870). Postlarval stage, complete, well-preserved specimen, visible in dorsal, ventral and lateral aspects (Figs. 1–4). Idiosoma (length 1050, width 570) markedly widened behind aspidosoma/ opisthosoma border and surrounded by cuticular rim, with four dorsal short rounded projections each bearing a tuft of long setae (Figs. 1C, E, 3A). Chelicerae not visible, hidden under hypostome. Hypostome long, narrow (Fig. 3B, C), with two ventral rows of 8–9 setae (setae not longer than twice the width of hypostome), and 1–2 lateral setae at apex, all setae setiform, barbed. Palps relatively slender (Fig. 2B, C). Palp tibia with one strong claw (odontus), accessory claw (paradont) not discerned; dorsal ctenidium represented by one spinose seta (Figs. 4C, D, 18A, B). Distally palp with numerous setiform setae (Figs. 4C, D, 18A, B), not aligned into rows (combs) dorsally or ventrally. Proximal part of palpfemur bears barbed setae (Fig. 3D). Palp tarsus oval, elongate, with numerous short setae, extending beyond termination of odontus, shorter than twice the length of odontus (Figs. 3E, F, 4C, D, 18 A, B). Aspidosoma clearly delimited, triangular in outline (Fig. 2B, D). Naso, sensillary area, crista metopica and eyes not discerned, obscured by long dorsal setae located above them. Long dorsal setae originating from four dorsal projections of two types: 1) numerous very long, slender, very densely ciliated or plumose, length of cilia at least twice the width of setal shaft (Fig. 17A, C), varying in length, longest 940, ratio to idiosomal length 0.84, density of cilia decreases to base of seta; 2) slightly shorter, thicker, rigid, spine-like, without cilia, with small irregularities (Fig. 17A, C). Plumose setae tend to appear distally near borders of tuft. Other idiosomal setae: 3) numerous long (130–200), densely ciliated or plumose, located on posterior part of idiosoma (Fig. 1E, I) and in anterior part of aspidosoma; 4) numerous moderately long, 2–3 times shorter than (3), ciliated, located in lateral and ventral parts of opisthosoma and on aspidosoma, absent on dorsal surface of opisthosoma (Fig. 1E, F); 5) rare moderately long (about two times shorter than (3), without cilia and with short spines, located in longitudinal rows dorso-medially on opisthosoma (Fig. 1F, G). Dorsal integument of opisthosoma distinctly reticulated with irregular cells of polygonal shape (Fig. 1H). Genital opening located behind level of coxae IV, surrounded by paired sclerites (valves) (Fig. 2B); each valve covered with setae. Anus surrounded with sclerotized valves and situated approx. half way between posterior margin of genital opening and termination of idiosoma (Fig. 2B). Legs moderately robust. Legs I and IV longer than II and III, and a little longer than idiosoma (Fig. 3A). Legs I with slightly wider segments than other legs. Leg segments covered with numerous setae of different kinds: ciliated, barbed or smooth (Fig. 3G–K). Tarsi II–IV long, each terminates with paired claws of similar size and shape (Fig. 3I–K), tarsus I slightly shorter, with pair of shorter claws (Fig. 3G, H), empodium not resolved. Paratype (IM-1177a). Postlarval stage, complete, well-preserved specimen (Figs. 5, 6), located at border between layers of amber and compressed in lateral direction (Fig. 6A, B); due to optical distortions, resolution in dorsal and ventral aspects limited. Left part of idiosoma dorsally obscured by bubble (Figs. 5A, B, 6A). Specimen mostly visible in lateral aspects (Fig. 5). Idiosomal length 1040, width 470 (but significantly underestimated due to lateral distortion). Types of idiosomal setation similar to holotype specimen, some details of setation better resolved in lateral aspects. Longest dorsal setae 740, ratio to idiosomal length 0.71. Dorsal surface of opisthosoma not resolved, obscured by long setae. Setation best resolved in lateral aspect (Fig. 5D) Chelicerae not visible, hidden under hypostome. Hypostome long, narrow, with two ventral rows of at least 9 barbed setae, and 1–2 lateral setae at apex (setae not longer than double width of hypostome) (Fig. 6D). Palps relatively slender (Fig. 6C), details well visible in lateral aspect (Fig. 18C–E). Left palp viewed in medio-lateral aspect shows a structure that can be interpreted either as a weakly developed paradont or as a single spinose seta of ctenidium (Fig. 18C, D, arrow). Setae on palp smooth, barbed and ciliated (in proximal part of palp). Palp tarsus oval, elongate, slightly longer than odontus (Fig. 18C, D). Crista metopica with two sensillary areas located next to each other, PSA with indistinct posterior process (Fig. 5C). Naso not discerned, obscured by legs. Front legs are raised in antenna-like fashion (Fig. 5A, B, D). Larva: unknown. Etymology. Punkochyzeria minaevi sp. nov. is named after Ilya G. Minaev (Ryazan, Russia), the owner of the studied specimens. Ilya has provided the amber pieces for our study and has kindly donated three holotype specimens for permanent deposition in the museum collection. Remarks. Although not all characters are resolved in both studied specimens, we consider them conspecific based on a number of similarities: details of long dorsal setae (Fig.17A–C), of other idiosomal setae and morphology of palps (Fig.18A–E). The reticulations of integument of the dorsal opisthosoma (Fig. 1H) could be confused with an artifact either remaining after the loss of numerous setae, usually covering the body in Pteridopodinae (Mayoral et al. 2018) or resulting from the incorrect focusing at setal bases or terminations. However, the imaging of the same surface with CLSM clearly shows that most of the dorsal opisthosoma lacks setation, with only a central longitudinal row of setae and a couple of setae lateral to it clearly fluorescent against the darker body cuticle (Fig. 1E, F). In addition, the extracted fragment of dorsal opisthosomal cuticle of another species of Punkochyzeria gen. nov. (P. khoyi sp. nov.) was imaged using different methods, including SEM (see below), which confirmed the presence of the polygonal structure of the dorsal integument. In both specimens setation was better resolved by CLSM (compare Figs. 2B and D, 6B and C). A single strong seta above the base of odontus (Fig.18 C, D, arrow) could be initially considered a weakly developed paradont. However, the other two species of Punkochyzeria gen. nov. possess similarly shaped spinose setae aligned in a row of three or five (=ctenidium) (Fig. 18 F, I, arrows). Given this, we consider this seta in P. minaevi sp. nov. as representing a ctenidium. Despite that, in P. minaevi sp. nov., the number of spinose dorsal setae near the base of odontus is uncertain (one or two, Fig. 18 A, B), we consider this number as one of the species-specific characters. The lifetime loss of the ctenidium setae is unlikely, as both studied specimens show similar morphology of each of the palps.
Authors: Kolesnikov, Vasiliy B., Turbanov, Ilya S., Vorontsov, Dmitry D.
Language: English
Topic: Study of Mite Species
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7079624672
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