Hylophthirus spinosus Durden, Beati, Greiman & Abramov 2024, new species
Creators: name: Durden, Lance A.
name: Beati, Lorenza
name: Greiman, Stephen E.
name: Abramov, Alexei V.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Psocodea
Enderleinellidae
Hylophthirus
Hylophthirus spinosus

description: Hylophthirus spinosus Durden, Beati, Greiman & Abramov, new species
(Figs. 1–4)
Type Host: Hylopetes alboniger (Hodgson, 1836) —particoloured flying squirrel (Rodentia: Sciuridae: Pteromyinae).
Type locality: Laos.
Description
Male (n = 6) (Figs. 1A, 2A, 3A, 3B, 3C, 3D). Total length of Holotype, 0.495 mm (mean, 0.486 mm, range, 0.464 –0.525 mm). Integument distinctly mamillated in certain areas and smooth in other regions (Fig. 2A). Head longer than wide with broadly rounded lateral margins and broadly tapering anterior margin; maximum head width of Holotype, 0.095 mm (mean, 0.093 mm, range, 0.091 –0.097 mm); dorsal head suture wide and distinct. Ventral head with large, sclerotised plate with anterolateral lobe on each side. One dorsal posterior central head seta, 2 dorsal marginal head setae, 2 sutural head setae, 1 supraantennal head seta, 2 preantennal head setae, 1 dorsal anterior head seta, 2 anterior marginal head setae and 1–2 oral setae on each side. Antennae five-segmented; segment 1 wider than long, segments 2 and 5 much longer than wide, segments 3 and 4 slightly longer than wide, segment 5 slightly bulbous and bearing terminal sensilla. Thorax wider than head; maximum thorax width of Holotype, 0.154 mm (mean, 0.156 mm, range, 0.154 –0.159 mm). Thoracic sternal plate (Fig. 3B) very broad and subtrapezoidal with acuminate anterolateral apex on each side. Notal pit absent. Mesothoracic spiracles small (diameter, 0.005 mm in all specimens) and each borne on distinct protuberance; dorsal mesothoracic seta adjacent to spiracle; two shorter more central dorsal setae present on each side of thorax. Forelegs and midlegs each terminating in small tibiotarsal claw, hindlegs terminating in massive tibiotarsal claw with distinct striations; all legs with subtriangular coxae, fore and mid coxae abutting each other ventrally, gap present between mid and hind coxae ventrally. Abdomen wider than thorax with 9 broad tergites dorsally, abutting each other; tergite 2 extending posteriorly on each side to partially cover sternite 3 laterally. Dorsally, 1 small tergal abdominal seta (TeAS) on each side on tergite 1, 2 small TeAS on each side on tergite 2, 2 longer TeAS on each side on tergites 3 and 4, 1 long TeAS on each side on tergites 5–7, 1 long medial TeAS and 1 short lateral TeAS on each side on tergite 8 and 1 short TeAS on each side on tergite 9. Posteriorly, ~4 short Dorsal Central Abdominal Setae (DCAS), followed by 1 short DCAS and 4 longer terminal setae on each side. Ventrally, 4 narrow sternites (on segments 3–6); 2 long, narrow Ventral Central Abdominal Setae (VCAS) on each side, followed by 2 long, robust Sternal Abdominal Setae (StAS) on each side on each sternite, then 1 long VCAS, 1 short VCAS and 2 short VCAS on each side. Lateral StAS on sternites 2–4 massive, each curving to acuminate posterior apex (Fig. 3C). Paratergal plates (Fig.3C) present on abdominal segments 2, 3, 4, 7 and 8; all plates subtriangular; paratergal plate I small, lacking spiracle and with pair of short PrS; paratergal plate II with small spiracle and pair of slightly longer PrS; paratergal plate III with small spiracle and pair of long PrS; paratergal plate IV lacking spiracle and with pair of long PrS; paratergal plate V lacking spiracle and with pair of extremely long PrS; small lateral spiracles, unaccompanied by paratergal plates, present on each of abdominal segments 5 and 6 (between paratergal plates III and IV).
Genitalia (Figs 3A, 3D) with subgenital plate (Fig. 3A) extending anteriorly to abdominal segment 7, with sinuous anterior and lateral margins, narrowing centrally, then expanding posteriorly. Basal apodeme (Fig. 3D) broad, terminating in large, wide, bifid arms posteriorly; parameres (Fig. 3D) curved and extremely narrow; pseudopenis with very narrow anterior margins and extending posteriorly well beyond apices of parameres; aedeagus (Fig. 3D) elongated and narrowing posteriorly to gonopore.
Female (n = 3) (Figs. 1B, 2B, 4A, 4B, 4C, 4D). Morphology as in male unless otherwise stated. Total body length of Allotype, 0.545 mm (mean, 0.554 mm, range, 0.534 –0.583 mm). Maximum head width in Allotype, 0.099 mm (mean, 0.100 mm, range, 0.099 –0.110 mm), with ventral sclerotised plate differing slightly in shape from that of male (Figs. 2B, 4A). Maximum thorax width, 0.164 mm (mean, 0.162 mm, range, 0.158–0165 mm); thoracic sternal plate (Fig. 4B) similar to that of male but subterminal hump present anterolaterally on each side. Abdomen with 6 broad, well separated, tergites dorsally and 6 sternites ventrally; sternites 1–5 narrow, sternite 6 broad. One long DCAS anteriorly, then 2 long TeAS on tergites 1–4, followed by 1 short TeAS on tergite 5 on each side. Sternite 1 with 2 long, narrow StAS, sternites 2–5 each with 2 extremely stout StAS, with lateral StAS as massive acuminate spines, and sternite 6 with 1 short StAS on each side. Paratergal plates, paratergal spiracles and PrS as in male although exact shape of paratergal plates slightly different (Fig. 4C). Genitalia (Fig. 4D) with small, poorly sclerotised, subcircular subgenital plate with broadly curved posterior and anterior margins; anterior margin with shallow central notch; posterior margin with 10 small setae; subgenital plate flanked on each side by broad accessory plate each bearing 4 small setae along curved posterior margin. Gonopods VIII and IX greatly enlarged and extending well beyond apex of abdomen; gonopods VIII smaller than, and internal to, gonopods IX, with straight lateral margins and each bearing 2 small setae, medial seta smaller than lateral seta; gonopods IX massive and possibly having expandable integument (see one gonopod IX in Fig. 2B), curving medially to acuminate apex and bearing 2 small setae near both medial and lateral margins. Genital opening flanked by 8–10 small setae and one longer seta on each side; 3 short setae on each side at apex of abdomen.
The host specimen is deposited in the Zoological Institute of the Russian Academy of Sciences in Saint Petersburg, Russia (ZIN). Collection data: No ZIN 98664; field No AA, AT 106; 17 November 2008; Laos: Khammouane Province, 18 km north of Thakhek, near Ban Doy Village (17033 ’26”N, 104049 ’28”E), elevation 140 m. Collectors: A.V. Abramov and A.N. Tikhonov.
Material examined
Type material. Holotype ♂ with data as above for the host (USNMENT 00981917); deposited in the Department of Entomology, U.S. National Museum of Natural History (Smithsonian Institution), Washington D.C., U.S.A. (USNMNH). Paratypes: 1♂, 2♀ (USNMENT 00981918) same data as holotype, deposited in USNMNH. 1♂, 1♀ (L3865, L3866) same data as holotype, deposited in the Zoological Institute of the Russian Academy of Sciences, Saint Petersburg, Russia. 1♂, 1♀ (L3861, L3862) same data as holotype, deposited in the collection of the first author which is willed to the USNMNH.
Non-type material: 2♂ (L3863, L3864), same data as type material. These specimens are slightly distorted following DNA extractions. Deposited in the collection of the first author.
Etymology. The species epithet refers to the robust spines (modified setae) on the ventral abdomen of both sexes of the new species.
description: Published as part of Durden, Lance A., Beati, Lorenza, Greiman, Stephen E. & Abramov, Alexei V., 2024, A new genus and new species of sucking louse (Phthiraptera: Anoplura: Enderleinellidae) from the particoloured flying squirrel (Hylopetes alboniger) in Laos, and an updated identification key to enderleinellid genera, pp. 545-561 in Zootaxa 5405 (4) on pages 548-553, DOI: 10.11646/zootaxa.5405.4.4, http://zenodo.org/record/10603809