Patrus nanensis Suksai &amp; Gustafson &amp; Sites &amp; Sangpradub 2021, sp. nov.
Creators: name: Suksai, Benjamart
name: Gustafson, Grey T.
name: Sites, Robert W.
name: Sangpradub, Narumon
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Gyrinidae
Patrus
Patrus nanensis

description: <i>Patrus nanensis</i> sp. nov. (Figs. 2E, 3E, 4E, 9, 14B) <b>Type material.</b> HOLOTYPE: male (card mounted; aedeagus in microvial), " THAILAND: Nan Province: Khun Sathan Natl. Park., Ban Khun Sathan, San Ta Subdistrict, Na Noi District, 18°16'24.12"N 100°29'10.80"E, 1474 m a.s.l., 30.V.2017, leg. P. Sapewisut " (THNHM). PARATYPES (6 exs): <b>THAILAND: Nan Province:</b> Khun Sathan Natl. Park., Ban Khun Sathan, San Ta Subdistrict, Na Noi District, 18°16'24.12"N 100°29'10.80"E, 1474 m a.s.l., 30.V.2017, leg. P. Sapewisut, 1 male (KKU), 2 females (THNHM, UMC); same locality except for, water supply weir, San Ta Subdistrict, Na Noi District, 18°16'42.06"N 100°30'26.95"E, 1356 m a.s.l., 30.V.2017, leg. P. Sapewisut, 1 male (UMC). <b>Diagnosis.</b> Body form in lateral view weakly dorsoventrally convex; elytral glabrous region of male (Figs. 2E, 9A) cordiform, along suture extending ca. 7/9 length of elytra, laterally expanded in anterior 2/3 to considerably wider than pronotal glabrous region, posterior 1/3 strongly acuminate with rounded margins; female elytral glabrous region (Figs. 3E, 9E) dissimilar to male, broad in anterior 4/5 occupying 9/11 elytral width, abruptly acuminate medially in posterior 1/3, posterolateral corners produced into acute points; elytral apex of both sexes similar, obliquely truncate without apicolateral sinuation, epipleural angle distinct, weakly rounded; male protibia (Fig. 4E) wedge-shaped, protibial apex truncate without prominent distolateral angle; male protarsus (Fig. 4E) ca. 1/2 length of protibia, protarsomeres width gradually decreasing apically; mesoventrite without medial pit; aedeagus (Fig. 9B–D) with median lobe tapered, apex strongly constricted to a small needle-like point; apex not constricted in lateral view (Fig. 9C); female reproductive tract (Fig. 9G) without additional sclerite between gonocoxae (Fig. 9F), fertilization duct as in Fig. 9H. <b>Description.</b> <i>Habitus</i>. Size. Male: TL = 10.4–10.7 mm, TW = 6.0– 6.2 mm; female: TL = 10.6–10.7 mm, TW = 5.7–5.8 mm. Body form elongate oval, evenly attenuated anteriorly and posteriorly, maximum width just posterior of humeral angle; in lateral view dorsoventrally weakly convex, maximum convexity posterior to scutellar region, evenly depressed anteriorly and posteriorly. <i>Coloration</i> (Figs. 2E, 3E). Dorsally head, pronotum, and elytra margined with golden pubescence; glabrous regions of head pronotum and elytra black with reticulation creating brassy sheen. Pronotal and elytral lateral margins dark. Venter dark, reddish brown to black. Middle and hind legs from trochanter to tarsus and ultimate abdominal ventrite lighter in color, red to orangish red. <i>Head</i>. Head capsule broad, convex. Labrum short, ca. 3.5× wider than long; setose medially with setae situated in large deep punctures; apex broadly rounded. Clypeus narrow, ca. 1/2 width of labrum; strongly reticulate and densely punctured, reticulation hatched in appearance with numerous short, well-impressed transverse lines. Frons similarly with strong hatched reticulation and dense punctation; pseudofrontal ridge present; furrow beneath pseudofrontal ridge without setae. Vertex also with strongly impressed hatch reticulation and dense punctation between dorsal eyes, reticulation becoming effaced in narrow band on occipital region. Dorsal eye delimited by strong orbital furrow; distance between dorsal eyes ca. 2.75× diameter of an eye; interorbital area strongly setose. <i>Thorax.</i> Pronotum (Figs.2E, 9A) with narrow lateral margins; pronotal transverse impressed line absent; lateral pubescence anteriorly extending onto pronotal disc as far as 2/3 width of dorsal eye; pronotal glabrous region densely and uniformly punctate with small weakly impressed punctures, strongly reticulate with uniform wellimpressed hatched reticulation similar to frons and vertex. Scutellar shield visible. Protrochanter with setose line along ventral (anterior) face. Profemur with setigerous punctures along anterior margin of ventral face, posterior margin of ventral face with row of setae along basal 2/3 ending with patch of longer denser setae. Protibia (Fig. 4E) wedge shaped in males, not constricted basally, ventral (inner) margin nearly straight; distal apex truncate, distolateral angle without prominence. Male protarsus (Fig. 4E) ca. 1/2 length of protibia, protarsomeres with distolateral angle round, not overlapping following tarsomere, lateral margins weakly rounded, fifth tarsomere 2× length of fourth, with lateral margins weakly rounded. Elytra (Figs. 2E, 9A) with narrow lateral margins gradually widened apically; glabrous region cordiform, elytral glabrous region along suture extending ca. 7/9 length of elytra, laterally expanded in anterior 2/3 to just wider than pronotal glabrous region, posterior 1/3 strongly acuminate with rounded margins; reticulation and punctation similar to pronotal glabrous region; elytral apex obliquely truncate, without apicolateral sinuation, epipleural angle distinct, weakly rounded, sutural angle straight forming near 90° angle. Mesoventrite without medial pit. <i>Sexual dimorphism</i>. Female smaller in size with narrow maximum width. Glabrous region of female elytra different (Figs. 3E, 9E), extending ca. 7/9 length of elytra, broad in anterior 4/5 occupying 9/11 elytral width, lateral margins straight creating parallel-sided appearance, abruptly acuminate medially in posterior 1/3 with posterolateral corners produced into acute points, posterior margin unevenly convex towards suture with subtruncate appearance; in lateral view width of pubescent margin at humeral region nearly equal to that extending posterior. Protibia of female narrower with more strongly prominent distolateral angle. Female protarsus unexpanded, narrow and parallel-sided in appearance. Male genitalia. Aedeagus (Fig. 9B) with median lobe just shorter than parameres, median lobe tapered for 3/5 length, parallel-sided in apical 1/3 before acumination, acumination short, 1/5 length of median lobe, apex strongly constricted to a small needle-like point; apex not constricted in lateral view (Fig. 9C), operculum as in (Fig. 9D); parameres narrowly rounded apically (Fig. 9B). Female genitalia. Reproductive tract with large sac-like spermatheca (Fig. 9G); fertilization duct sclerotized, highly convoluted (Fig. 9H); small sclerite present posterior to oviduct; additional round sclerite between gonocoxae absent; gonocoxae narrow, apically narrowly rounded, lateral margins weakly curved (Fig. 9F). <b>Variation.</b> There is considerable variation in size and width among the specimens examined. Large males weakly broader in total body width than smaller males. <b>Differential diagnosis.</b> <i>Patrus nanensis</i> <b>sp. nov.</b> is most similar to <i>P. apicalis</i> and <i>P. subapicalis</i>. Males of <i>P. nanensis</i> <b>sp. nov.</b> can be readily distinguished by the shorter protarsi, which are about 1/2 the length of the protibia, and the width of the protarsomeres gradually decreases apically (Fig. 4E), compared to the other two species, which have longer male protarsi that are about 3/4 the length of the protibia, and the width of protarsomeres 1–4 are mostly subequal throughout (Fig. 4A, H). The aedeagus of <i>Patrus nanensis</i> <b>sp. nov.</b> (Fig. 9B) though similar in form to that of <i>P. apicalis</i> (Fig. 5B) can be distinguished by the narrower and more needle-like apex of the median lobe as well as by the more narrowly rounded parameres. The aedeagus of <i>P. subapicalis</i> is considerably different (Fig. 12B) as it lacks a needle-like apex to the median lobe. Females of <i>nanensis</i> <b>sp. nov.</b> can be distinguished by the elytral glabrous region which is relatively narrower, occupying 9/11 of the elytral width (Fig. 9E) compared to that of <i>P. apicalis</i> and <i>P. subapicalis</i>, in which it occupies 10/11 of the elytral width (Figs. 5E, 12E). Further, they have a differently shaped posterior margin of the elytra, being unevenly convex toward the suture with some extent of the convexity appearing subtruncate in the former, compared to evenly convex and rounded towards the suture in the latter two species. Finally, a well-impressed medial pit is always present on the mesoventrite of males of <i>P. apicalis</i>, whereas it is frequently absent in both sexes of <i>P. nanensis</i> <b>sp. nov.</b> <b>Etymology.</b> The specific epithet is an adjective in reference to the province where this new species was found. <b>Distribution.</b> This species is currently known from only one high-elevation stream in Khun Sathan National Park, Nan Province, Thailand (Fig. 14B).
description: Published as part of <i>Suksai, Benjamart, Gustafson, Grey T., Sites, Robert W. &amp; Sangpradub, Narumon, 2021, Review of the Patrus landaisi species group from Thailand with description of three new species (Coleoptera, Gyrinidae), pp. 561-591 in Zootaxa 4991 (3)</i> on pages 577-578, DOI: 10.11646/zootaxa.4991.3.8, http://zenodo.org/record/5042656