Patrus landaisi ( Régimbart, 1892 )

Suksai, Benjamart, Gustafson, Grey T., Sites, Robert W. & Sangpradub, Narumon, 2021, Review of the Patrus landaisi species group from Thailand with description of three new species (Coleoptera, Gyrinidae), Zootaxa 4991 (3), pp. 561-591 : 575-577

Patrus landaisi ( Régimbart, 1892)

( Figs. 2D , 3D , 4D , 8 , 13C, 13E, 13F , 14A )

Orectochilus landaisi Régimbart, 1892: 693 (original description)

Orectochilus (Patrus) landaisi Régimbart, 1892 : Ochs 1930: 27

Patrus landaisi Régimbart, 1892 : Hájek & Fery 2017: 29 (new combination, catalogue)

Type locality. Cao B ằng Province, Vietnam .

Type material examined. SYNTYPE female ‘Tonkin int- / env. De Cao bang [beige label, handwritten black ink]’ ‘MUSEUM PARIS / COLL MAURICE REGIMBART / 1908 [beige label, typed black ink]’ ‘ SYNTYPE [red label, typed black ink]’ ‘ SYNTYPE / Orectochilus / landaisi Régimbart, 1892 / [white label, typed black ink]’ ‘MNHN / EC10156 [white label, typed black ink]; SYNTYPE female same locality except for, EC10157.

Other material examined. THAILAND: Chiang Rai Province: Stream close to Ban Phithak Thai, Tap Tao Subdistrict , Thoeng District , 19°45’00.55”N 100°23’59.53”E, 1089 m a.s.l., 2.V.2019, leg. B. Suksai, P. Sapewisut & N. Plangklang, 1 female ( THNHM) ; Stream close to Ban Thai Samakkhi, Tap Tao Subdistrict , Thoeng District , 19°44’13.3”N 100°24’02.2”E, 1299 m a.s.l., 10.XI.2018, leg. B. Suksai, S. Kullasoot & P. Sapewisut, 7 males ( GTGC, KKU, THNHM) , 7 females ( KKU, THNHM) ; same locality except for, 2.V.2019, leg. B. Suksai, P. Sapewisut & N. Plangklang, 5 males, 8 females ( GTGC, THNHM, UMC) ; same locality except for, 19°44’35.45”N 100°24’05.91”E, 1263 m a.s.l., 28.V.2017, leg. P. Sapewisut, 9 females ( KKU, THNHM) .

Diagnosis. Size: Male: 11.8–13.0 mm, female: 10.8–12.2 mm; body form in lateral view weakly dorsoventrally convex; elytral glabrous region of male ( Figs. 2D , 8A ) 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. 3D , 8E ) dissimilar to male, broad in anterior 2/3 occupying 10/11 elytral width, lateral margins nearly straight creating parallel-sided appearance, abruptly acuminate medially in posterior 1/3, posterolateral corners not jagged and not produced into points, posterior margin near-evenly convex toward suture; elytral apex of both sexes similar, obliquely truncate without apicolateral sinuation, epipleural angle distinct, rounded; male protibia ( Fig. 4D ) club-shaped, without basal constriction, protibial apex obliquely truncate with prominent distolateral angle; male protarsus ( Fig. 4D ) ca. 1/2 length of protibia, protarsomeres 1–4 mostly similar in width, lateral margins weakly rounded; mesoventrite without medial pit; aedeagus ( Fig. 8B–D ) with median lobe weakly tapered, apical 1/6 of aedeagus acuminate with nearly straight lateral margins, apex not constricted in lateral view ( Fig. 8C ); female reproductive tract ( Fig. 8G ) without additional sclerotized structure between gonocoxae ( Fig. 8F ), fertilization duct as in Fig. 8H .

Differential diagnosis. Patrus landaisi is most similar to P. garuda sp. nov. but can be distinguished by the differential diagnoses provided above. In general, the obliquely truncate elytral apices of P. landaisi should readily distinguish this species.

Distribution. This species is known from northern Vietnam ( Régimbart 1892; Zaitzev 1910; Peschet 1923), southeastern China (Guizhou) ( Régimbart 1907; Wu 1931; Mazzoldi 1995) and Laos (without further details) ( Ochs 1930). The records from Chiang Rai Province ( Fig. 14A ) reported here are the first for Thailand, where it was found together with P. salvazai in a shallow stream ( Fig. 13C ) and puddles of a drying stream bed ( Fig. 13E–F ).

Figures

FIGURE 2. Dorsal habitus of males of P. landaisi species group: (A) P. apicalis; (B) P. corpulentus; (C) P. garuda sp. nov.; (D) P. landaisi; (E) P. nanensis sp. nov.; (F) P. phetchabunensis sp. nov.; (G) P. salvazai; (H) P. subapicalis. Scale bars = 4 mm.

FIGURE 3. Dorsal habitus of females of P. landaisi species group: (A) P. apicalis; (B) P. corpulentus; (C) P. garuda sp. nov.; (D) P. landaisi; (E) P. nanensis sp. nov.; (F) P. phetchabunensis sp. nov.; (G) P. salvazai; (H) P. subapicalis. Scale bars = 4 mm.

FIGURE 4. Left protibia and protarsus of males of P. landaisi species group: (A) P. apicalis; (B) P. corpulentus; (C) P. garuda sp. nov.; (D) P. landaisi; (E) P. nanensis sp. nov.; (F) P. phetchabunensis sp. nov.; (G) P. salvazai; (H) P. subapicalis. Scale bars = 2 mm.

FIGURE 8. Patrus landaisi: (A) male pronotum and elytra, dorsal view, scale bar = 4 mm; (B) aedeagus, dorsal view, scale bar = 1 mm; (C) apex of median lobe, lateral view, scale bar = 1 mm; (D) apex of median lobe, ventral view showing operculum, scale bar = 1 mm; (E) female pronotum and elytra, dorsal view, scale bar = 4 mm; (F) gonocoxae, ventral view; (G) female reproductive tract, ventral view, bursal gland not shown, scale bar = 1 mm; (H) fertilization duct, ventral view.

FIGURE 13. Habitats of P. landaisi species group: (A) stream at Siriphum Waterfall, Doi Inthanon National Park, Chiang Mai Province, habitat of P. garuda sp. nov. and P. subapicalis; (B) Benjamart Suksai in habitat of P. apicalis and P. salvazai at Nam Kuen stream, Chiang Rai Province; (C) shallow stream close to Ban Thai Samakkhi, Chiang Rai Province, habitat of P. landaisi and P. salvazai; (D) Tham Yai Waterfall Phu Kradueng National Park, Loei Province, habitat of P. phetchabunensis sp. nov.; (E) puddle in dry stream bed close to Ban Phithak Thai, Chiang Rai Province, habitat of P. landaisi and P. salvazai; (F) P. landaisi and P. salvazai from puddle in dry stream habitat close to Ban Thai Samakkhi, Chiang Rai Province.

FIGURE 14. (A–B) Distribution records of the P. landaisi species group in Thailand.