Porrorhynchus (Porrorhynchus) landaisi Régimbart, 1892

Gustafson, Grey T. & Miller, Kelly B., 1835, Revision of the Southeast Asian Whirligig Beetle GenusPorrorhynchusLaporte, 1835 (Coleoptera: Gyrinidae: Gyrininae: Dineutini), The Coleopterists Bulletin 1835 (4), pp. 675-714 : 675-714

Porrorhynchus (Porrorhynchus) landaisi Régimbart, 1892

( Figs. 1B , 2A , 6A–K , 7 , 13A , 14 , 16C–E )

Porrhorrhynchus landaisi Régimbart 1892a: 667 , 740 [original description, checklist], 1902: 5, Fig. 12 [distribution, partial dorsal habitus], 1907: 152 [description of habitat, collection information]; Peschet 1923: 123 [review]; Hatch 1926a: 311, Pl. XX 3, 9, 16, 17, 21, Pl. XXI 29, 41, Pl. XXII 47, 60, 64, Pl. XXIII 80, Pl. XXIV 90, 98 [morphology], 1926b: 437, 450 [size, minor description].

Porrhorrhynchus barthelemyi Régimbart 1902: 5 [nomen nudum], 1907: 153 [original description]. New synonymy.

Dineutus (Porrorhynchus) barthelemyi: Ochs 1926: 139 [checklist], 1930: 15 [catalog].

Dineutus (Porrorhynchus) landaisi: Ochs 1926: 139 [checklist], 1929b: 719 [distribution], 1930: 16 [catalog]; Wu 1931: 71 [distribution].

Dineutus (Porrorhynchus) landaisi latilimbus: Ochs 1926: 139 [nomen nudum in checklist], 1926: 193 [original description], 1929b: 719 [distribution], 1930: 16 [catalog], 1942: 206 [holdings]; Wu 1931: 71 [distribution]. New synonymy.

Dineutus landaisi latilimbus: Kamiya 1936: 14 , fig. 19 [description, dorsal habitus].

Porrorhynchus landaisi landaisi: Mazzoldi 1995: 162 [distribution].

Porrorhynchus landaisi latilimbus: Mazzoldi 1995: 162 [distribution]; Jäch and Li 1998: foreword [notes on distribution].

Porrorhynchus sp. : Jäch et al. 2012: 66 [distribution].

Type Material Examined. Porrorhynchus landaisi Régimbart, 1892 lectotype here designated (1 ♀ pinned, Fig. 16C ): “ Environs de/ Cao-Bang./ Tonkin Landais [white label, handwritten in black ink, handwriting appears to be Régimbart’ s]/ MUSEUM PARIS COLL MAURICE REGIMBART/ 1908 [white label with thin black border, type black ink]// LECTOTYPE [red label, typed black ink]//” (1 ex. MNHN) . Paralectotypes (1 ♂ pinned [prothorax clearly glued back on, head glued back on]): “Tonkin, Hanoi / Landais [white label, handwritten in black ink, handwriting appears to be Régimbart’ s]// MUSEUM PARIS/ COLL MAURICE REGIMBART/ 1908 [white label with thin black border, typed black ink]// TYPE [red label, typed black ink]// PARALECTOTYPE [red label, typed black ink]//” (1 ex. MNHN); (1 ♀ pinned) : “ Hanoi / Landais [white label, handwritten in black ink, handwriting appears to be Régimbart’ s]// MUSEUM PARIS COLL MAURICE REGIMBART/ 1908 [white label with thin black border, type black ink]// PARALECTOTYPE [red label, typed black ink]//” (1 ex. MNHN) .

Porrorhynchus barthelemyi Régimbart, 1907 lectotype here designated (1 ♂ pinned, aedeagus dissected on point, Fig. 16E ): “ MUSEUM PARIS/ ANNAM / DÉCION DE QUANG NAM/ AU NHA TRANG/ C te DE BARTHÉLEMY 1899 [brown label, typed black in]// Dans le Aroyos / des Moïs / à 1700 m. d’ altitude [brown label, handwritten in black ink, unknown handwriting]// MUSEUM PARIS/ Annam/ C te Barthelémy/ 1899 [brown label, MUSEUM PARIS printed in black ink, rest handwritten, unknown handwriting]// MUSEUM PARIS/ COLL MAURICE REGIMBART / 1908 [white label with thin black border, typed black ink]// LECTOTYPE [red label, typed black ink]//” (1 ex. MNHN) . Paralectotype (1 ♀ pinned): Same labels as lectotype except without the final two MUSEUM PARIS labels and with “TYPE [red label, typed black ink]// PARALECTOTYPE [red label, typed black ink]//” (1 ex. MNHN) .

Dineutus (Porrorhynchus) landaisi latilimbus Ochs, 1926 lectotype here designated (1 ♂ pinned, Fig. 16D ): “ ♂ [white label, printed black ink]// China / Insel Hainan/ 10.-25.III.09/ H.Schoede S.G. [beige label, typed black ink, except date which is handwritten in black ink]// Coll./ G.Ochs [white label, typed black ink]// Para-/ typoid [red label with black border, typed black ink]// latilimbus Ochs [beige label with black bor- der, handwritten in ink, handwriting appears to be Ochs’]// LECTOTYPE [red label typed black ink]” (1 ex. SMF) . Paralectotype (1 ♀ pinned): Same data as lectotype except with ♀ label and without latilimbus Ochs label and “ PARALECTOTYPE [red label, typed black ink] (1 ex. SMF) .

Type Designations. Régimbart (1892a), in his original description of P. landaisi , mentions having examined three specimens (one male and two females) from Tonkin, collected by M. A. Landais. The exact locality given by Régimbart is Ban-Khau , to the south of Cao-bang. Of the material examined in the MNHN Régimbart collection, there are four specimens with handwritten labels by Régimbart with Landais listed as the collector. Three are listed as being from Tonkin (one male with a glued head and thorax and two intact female specimens), the other specimen has only Tuyen Quan as the locality. Therefore, we consider the three specimens with Tonkin on the label as the original syntype series. As the only specific locality provided by Régimbart mentions Cao-Bang , we here designate the female specimen, with Cao-Bang as the locality and Landais as collector, the lectotype . This specimen is also completely intact. The male specimen from the syntype series, while carrying a type label, is heavily damaged and has not been formerly designated as a lectotype. For this reason, we consider the male and the second female specimens as paralectotypes .

Ochs (1926), in his original description of P. landaisi latilimbus , does not specify how many specimens were examined, but he does describe both a male and female, implying more than a single specimen involved. Since no specimen was explicitly designated as the holotype, the series must be regarded as syntypes. We here designate the large male specimen as the lectotype for P. landaisi latilimbus . A lectotype was also designated for P. barthelemyi to stabilize the nomenclature. The male with its aedeagus dissected and available for study was selected as the lectotype.

Additional Material Examined. CHINA: leg. G. Liu (1 ex. MCZ); Hainan Island : leg. J Whitehead (1 ex. BMNH), Kiung-ah an Dist., Mt. ran go, 21-22.v.1935 , leg. P. K. To (2 ex. BPBM); 5 km NE Tian Chi, Jianfeng mtns, 800m, 22. i.1996 , leg. Jäch (4 ex. NHMW); same as previous except : leg. Ji & Wang (1 ex. NHMW), Jianfengling , 8.ix.1938 , leg. "Protector" (1 ex. ICRI); same locality as previous except: 8.xii.1981 , leg. B.R. Li (1 ex. ICRI); same as previous except: 22.ii.1982 , leg. R.L. Pan (1 ex. ICRI); same as previous except : leg. H.Q. Chen (2 ex. ICRI); Jianfengling Mts., Tiachi Lake env., BiSHU VILLA, 18°44′40″;N, 108°50′41″E, 950m, 9-11. v.2011 , leg. M. Fikáček, V. Kubeček & L. Li, at light (4 ex. NMPC) . Tibet: Zayü co., Xiachayu , vii.2011 , leg. Li Jingke (1 ex. NHMW). Yunnan: Kunming (" Yunnanfou "), ZML. 2010/ 336 (1 ex. MZLU) . VIETNAM: "Annam": 1895, leg. Barthélemy, coll. C.L. Legros (1 ex. MNHN) "Tonkin": (4 ex. NHMW); "Tonkin": ZML. 2010/ 341 (1 ex. MZLU). Bac Kan (" Backan "): viii.1907 , leg. P. Lemée, Oberthur Coll. / 1909- 159. (8 ex. BMNH); same as previous except: Oberthür Coll. (1 ex. MNHN), same as previous except: ZML. 2010/ 337-340 (5 ex. MZLU). Bắc Quang : "Bac-Quang", "Entre Hagiang et Vinh- Tuy", "Vallées de la Haute Riv. Claire", 1908 , leg. J. de Retz (2 ex. MNHN); " Thatkhé " , coll. R. Peschet (2 ex. MNHN). Kon Tum: ca. 20 km NE Ngoc Linh, 1-4m trib. of Ngoc Mi River , 15°08′23.5″N 107°54′40.2″E, 980m, 10.ix.1998 , leg. B. Hubley, D.C. Currie, & M. Tseng, 2° tropical forest, ROM 982314, (2 ex. ROME). Lào Cai: (" Laokay "), in WNW part, 12-13.viii.1934 , leg. Ernest R. Tinkham (1 ex. ICRI), Bao Hà ("Bao-Ha"); 24.x.1923 , leg. H. Stevens, Sladen- Goodman / Trust Exped. / B.M. 1924-329. (2 ex. BMNH). Ngh ệ An: Pu Mat ntl. Prk. Moi River , 18°57.085′N 104°48.746′E, 241m, 13.vii.2007 , leg. Sites & Trung, rocky stream, L-1014, (6 ex. UMRM); W of Con Cuong, Khe Moi Forestry Camp, Keh Moi River , 18°56′N 104°49′E, 308m, 27.x.1994 , leg. DC Currie, tropical forest, ROM 946108, ROMEnt Spec. No. 17526 - 17528 (3 ex. ROME); ca. 25 km SW of Con Cuông, Khe Moi River Forestry Camp , 18°56′N 104°49′E, 308m, 4.vi.1995 , leg. B. Hubley, pool in Khe Moi River, ROM 956157, ROMEnt Spec. No. 2145, 4595, 4607, 4619, 4643 (7 ex. 5 ROME, 2 CNC). Qu ẚng Ngãi : "Vie Klong", 97 km NE of Kon Tum (" Kontum "), 1140m, 10.vi.1960 , leg. R.E. Leech (1 ex. BPBM). Tuyên Quang (" Tuyen quan"): "Ruiss. Affluents de la Rivieu Claire" , leg. Capc A. Landais (1 ex. MNHN). Uncertain locality within Vietnam : "Haut Tonkin": "Rég de Bac Ken Ha-Giang, Quan-Ba et Yen-Minh": 1918 , leg. F. de Broissia (3 ex. MNHN). Uncertain localities: "Kouy-Tchéo": 1909 , leg. P. Cavalerie (2 ex. MNHN), " Kouy-Tchéo ": " Rég. de Pin-Fa", 1909 , leg. P. Cavalerie (23 ex. MNHN), same as previous except : coll. R. Peschet (3 ex. MNHN); same as previous except : coll. C.L. Legros (10 ex. MNHN) .

Type Locality. Cao B ằng Province, Vietnam .

Diagnosis. Labrum elongate and subtriangular. Antenna with seven complete flagellomeres and an eighth typically only complete along its posterior face ( Fig. 2A ). Yellow lateral margins nearly complete on elytra ( Fig. 1B ), extending to just anteriad elytral apices; interrupted in basal third by mediad constriction of yellow margin, associated in males with swelling for reception of fore leg. Elytral apices spinose, apicolaterally with sawtooth-like serration; sutural angle produced to a short point; two parasutural spines of similar size; last sawtooth-like spine at the epipleural angle larger and more projecting than rest ( Fig. 1B ).

Porrorhynchus landaisi can be distinguished from all other species of Porrorhynchus by the dorsal olive green color with nearly complete yellow lateral margins of the elytra, ending just anteriad elytral apex and interrupted in the basal third by a mediad constriction, and in the form of the spinose elytral apices with two parasutural spines.

Description. Size: ♂ L: 19.3 – 26.0 mm, W: 11.0– 14.1 mm; ♀ L: 17.9–21.2 mm, W 10.5–11.9 mm. Habitus: Largest member of genus; most specimens normally elongate oval in body form, attenuated anteriorly in large males; in lateral view, strongly convex, greatly humped in scutellar region, depressed posteriorly; in anterior/posterior view, very steeply sloped towards lateral margins from strongly humped scutellar region. Coloration: Head, pronotum, and elytra dorsally olive green; base of labrum yellow basomedially; pronotum and elytra with yellow lateral margins; turquoise blue reflections apicolaterally just posteriad to end of yellow lateral margins; venter yellow to yellowish orange; ultimate maxillary palpomere black, except for apex; fore legs with tibia black in proximal 1/2, profemur anteriorly with black ventral border for most of length. Head: Vertex with even covering of weakly impressed punctures, separated from nearest puncture by ca. 2–3X diameter of a puncture; orbital ridge without yellow margin, similarly colored as vertex; frons similarly punctate as vertex, fronto-lateral margins lightly wrinkled, frontoclypeal suture with posterior margin nearly straight, lateral margins nearly straight, meeting posterior margin at ca. 120°-

angle; clypeus with punctation most evident at anterior margin, punctures separated from nearest puncture by ca. 2–3X diameter of a puncture, becoming more densely spaced anteriorly; antennal flagellum with 7 complete flagellomeres, 8 th flagellomere present as incomplete suture on posterior face ( Fig. 1A ); labrum subtriangular, punctation absent basomedially in association with yellow coloration, strongly present apically, punctation well-impressed, dense, separated by 1.5–2.0X diameter of a puncture; maxillary/labial palpi dissimilar in shape ( Fig. 6C, G ), maxillary palpi broader, shorter with asymetrical dorsal/ventral margins, ventral margin more strongly curved than dorsal margin, labial palpi narrower, more elongate with anterior/posterior margins more similar, anterior margin nearly straight, posterior margin weakly curved. Thorax: Pronotum densely punctate, punctation consisting of medium sized, well-impressed punctures separated from nearest puncture by <1–2X diameter of a puncture, reticulation less impressed medially, becoming more well-impressed laterally, very shallow transverse depression often present medially, lateral marginal depression present; Protrochanteric setose patch situated paramedially; protibial spine projecting anterolaterally; male protarsi wide, fairly convex dorsally, shape as in Fig. 6A , ultimate protarsomere of male ca. <2X as long as wide; ultimate protarsomere of female ca. 2.5X length of penultimate; elytra with reticulation effaced in scutellar region along elytral suture, reticulation present apically/laterally, being most strongly impressed marginally, elytral disc with even covering of well-impressed, medium sized punctation, distance between nearest punctures ca. 1–2X diameter of a puncture; lateral marginal depression broad, expanded posteriad humeral region; yellow lateral margin nearly complete, ending just anteriad elytral apices, interrupted in basal 1/3 by constriction, in males associated with swelling created by cavity for reception of fore leg, apicolateral margins of elytra with triangular sawtooth-like spines, final spine at epipleural angle elongate, elytral apices spinose ( Fig. 1B ), with 2 parasutural spines, sutural angle produced; mesoventral apex noticeably acuminate; meso- and metacoxae similar, mesocoxal process broadly rounded, without projecting process; male mesotarsal claws as in Fig. 6D ,ventral margin broadly rounded, anterior claw apically narrowed; metacoxal process as in Fig. 6B , without distinct apicolateral corners, without sinuate lateral margins. Genitalia: Aedeagus ( Fig. 7A–C, E–G, I–K ) with median lobe ca. 5/6 length of parameres, weakly to moderate laterally expanded in apical 1/3, strongly acuminate in apical 1/6, apex truncate, in lateral view, apex briefly strongly curved dorsally; parameres in dorsal view weakly laterally expanded in apical 1/2, narrowly rounded, medially reflexed after apical 1/4, basally strongly constricted; in lateral view, ventral margin of parameres strongly curved anteriorly to posteriorly after basal 1/3. Female reproductive tract ( Fig. 13A ) with large tubiform spermatheca; gonocoxae with lateral margin straightly angled towards apex, apex obliquely truncate.

Sexual Dimorphism. Males tend to be larger in size than females. Some males exhibit a broader body form, having their outline laterally expanded posteriad elytral mid-length, giving large males a more attenuated feel, whereas females are more evenly narrowed anteriorly and posteriorly. The spines of the elytral apices tended to be longer and more pronounced in females, whereas in very large males they tended to be smaller and more blunt.

Variation. There is a considerable amount of size variation in this species in terms of body form ( Fig. 7D, H, L ). Several populations had very large males, especially those from Vietnam ( Fig. 7H ), while some, like those from Hainan Island, China, had very small and narrow males ( Fig. 7D ), but also some of the largest. Body form tended to change along with size as noted above. The male aedeagus also showed some variation, which is discussed in the discussion section below.

Distribution. Known primarily from southern China and northern Vietnam ( Fig 14 ). It is found as far west as Zayü Co., Tibet in China ( Porrorhynchus sp. in Jäch et al. 2012), through southern China, Vietnam as far south as the Central Highlands, and east to Hainan Island, China.

Biology. This species is lotic, being known from forested streams, based on the label data.

Discussion. This is the largest species of gyrinid known, approaching 30 mm in total length! The largest specimen examined during this study was ca. 29.5 mm (in MNHN in the Legro collection), including the labrum and abdomen. The next largest species of gyrinid known is Dineutus macrochirus Régimbart, 1899 , reaching 22.9 mm (without the abdomen) and from New Guinea ( Brinck 1984).

Porrorhynchus barthelemyi ( Fig. 16E ) was described from specimens from the Central Highlands region of Vietnam, inhabited by the Degar indigenous ethnic group, called the “Moïs” by the French ( Maître 1909). These specimens are more elongate and narrow in dorsal habitus, and the dorsal punctation is larger and denser than in other populations of P. landaisi , as noted by Régimbart in his original 1907 description. However, these are the only characters by which these specimens differ from others of P. landaisi , thus the name is here synonymized as it represents variation in a more southern population. Furthermore, the variation of a narrow body form is exhibited in other populations of P. landaisi . The ventral surface of the “ barthelemyi ” specimens appears to have become unnaturally discolored in certain sclerites ( Fig. 16E ). Porrorhynchus landaisi latilimbus was described by Ochs (1926) from Hainan Island and is distinguished from the nominal form only by having a broader yellow margin. However, there is variation in the width of the yellow margins of individuals, thus this subspecies distinction is based on simple color variation. No distinct morphological differences could be found between the Hainan populations ( Figs. 6A–D , 7A–C ) and those from the mainland ( Figs. 6E–H , 7E–H ), and this subspecies is here synonymized.

A very uniquely broad specimen ( Fig. 7L ) was purportedly collected from Tibet at a light trap ( Jäch et al. 2012). The specimen is unfortunately damaged, missing its labrum, and was the only one of its kind collected ( Fig. 7L ), preventing further accessment of the populational variation from this area. Aside from the broader habitus, the other morphological features are within the range of normal variation ( Fig. 6I–K ), including the aedeagus ( Fig. 7I–K ). This specimen, first published in Jäch et al. 2012 as Porrorhynchus sp. , extends the known range of the species much further west than previously known.

This species has a very unique antennomere count for gyrinids, having seven distinct, but an eighth noticeable along its posterior face. Most other gyrinid genera have either nine or six antennal flagellomeres, with only Enhydrus previously known to possess seven (Miller and Bergsten 2012).

No information is available on this species’ potential for sensitivity to water quality, but given that all other species of Porrorhynchus are, it is likely sensitive as well. This species has a more northeastern distribution in Southeast Asia ( Fig. 14 ) and one that is considerably smaller than that of P. marginatus . We propose the common name of the splendid snouted whirligig for P. landaisi .

Figures

Fig. 1. Porrorhynchus species, dorsal habitus. A) P. marginatus, B) P. landaisi, C) P. indicans, D) P. depressus, E) P. misoolensis. Scale bar = 5 mm.

Fig. 2. Porrorhynchus species, right antenna (anterior view above, posterior view below. A) P. landaisi, B) P. indicans, C) P. marginatus, D) P. depressus. Scale bars = 0.5 mm.

Fig. 6. Porrorhynchus species. P. landaisi from Hainan Island: A) Protarsus, scale bar = 1 mm, B) Metacoxal apex, scale bar = 0.5 mm, C) Maxillary (above) and labial (below) palpi, scale bar = 0.5 mm, D) Mesotarsal claws, scale bar = 0.5 mm. P. landaisi from Vietnam: E) Protarsus, scale bar = 1 mm, F) Metacoxal apex, scale bar = 0.5 mm, G) Maxillary (above) and labial (below) palpi, scale bar = 0.5 mm, H) Mesotarsal claws, scale bar = 0.5 mm. P. landaisi from Tibet: I) Protarsus, scale bar = 1 mm, J) Metacoxal apex, scale bar = 0.5 mm, K) Mesotarsal claws, scale bar = 0.5 mm. P. indicans: L) Protarsus, scale bar = 1 mm, M) Metacoxal apex, scale bar = 0.5 mm, N) Maxillary (above) and labial (below) palpi, scale bar = 0.5 mm, O) Mesotarsal claws, scale bar = 0.5 mm.

Fig. 7. Porrorhynchus landaisi. Specimen from Hainan Island: Aedeagus in A) Dorsal view, scale bar = 1 mm, B) Ventral view, C) Lateral view, and D) Dorsal habitus, scale bar = 5 mm. Specimen from Vietnam: Aedeagus in E) Dorsal view, scale bar = 1 mm, F) Ventral view, G) Lateral view, and H) Dorsal habitus, scale bar = 5 mm. Specimen from Tibet: Aedeagus in I) Dorsal view, scale bar = 1 mm, J) Ventral view, K) Lateral view, and L) Dorsal habitus, scale bar = 5 mm.

Fig. 13. Porrorhynchus species, female reproductive tract. A) P. landaisi, B) P. indicans, C) P. marginatus, D) P. depressus, E) P. misoolensis. More heavily sclerotized areas indicated in gray. Scale bars = 1 mm.

Fig. 14. Map showing distribution of Porrorhynchus s. str. species. Triangles = P. landaisi; circles = P. marginatus; square = P. indicans.

Fig. 16. Type specimens. A) Porrorhynchus brevirostris, lectotype and labels, B) Dineutes indicans, holotype, C) Porrorhynchus landaisi, lectotype and labels, D) Dineutus landaisi latilimbus, lectotype and labels, E) Porrorhynchus barthelemyi, lectotype (dorsal and ventral views) and labels.

Fig. 12. Porrorhynchus species. P. depressus from Omo River, Gulf Province, Papua New Guinea: Aedeagus in A) Dorsal view, scale bar = 1 mm, B) Ventral view, C) Lateral view, and D) Dorsal habitus, scale bar = 5 mm. P. depressus from Lorentz River, southwestern Irian Jaya: Aedeagus in E) Dorsal view, scale bar = 1 mm, F) Ventral view, G) Lateral view, and H) Dorsal habitus, scale bar = 5 mm. P. depressus from Nabire, western Irian Jaya: Aedeagus in I) Dorsal view, scale bar = 1 mm, J) Ventral view, K) Lateral view, and L) Dorsal habitus, scale bar = 5 mm. P. misoolensis: Aedeagus in M) Dorsal view, scale bar = 1 mm, N) Ventral view, O) Lateral view, and P) Dorsal habitus, scale bar = 5 mm.