Porrorhynchus (Porrorhynchus) indicans ( Walker, 1858 )

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) indicans ( Walker, 1858)

( Figs. 1C , 2B , 5 , 6L–O , 13B , 14 , 16A–B )

Dineutes indicans Walker 1858: 205 [original description].

Porrhorhynchus brevirostris Régimbart 1877a: 33 [original description], 1877b: 113, pl. 6, Fig. 5 [redescription, dorsal habitus, synonymy by Régimbart 1886b: 250], 1882: 429, pl. 11, Fig. 50 [redescription, elytron], 1884: 471 [checklist].

Porrhorrhynchus brevirostris: Régimbart 1886b: 250 [misspelling].

Porrhorrhynchus indicans: Régimbart 1886b: 250 [new status], 1892a: 740 [checklist], 1902: 5 [distribution].

Dineutus (Porrorhynchus) indicans: Ochs 1926: 139 [checklist], 1929a: 248 [distribution].

Porrorhynchus (Ceylorhynchus) indicans: Brinck 1955: 103 [new status], 1980: 106, figs. 2-6 [description, morphology].

Porrorhynchus indicans: Vazirani 1969: 403 [distribution].

Type Material Examined. Dineutes indicans

Walker, 1858 lectotype here designated (1 ♂

pinned, Fig. 16B ): “ Type [beige disc, typed black ink, red circle around font]// Ceylon [blue disc, handwritten in black ink, handwriting unknown]// indicans Walker / Ann. Nat Hist (Type) [blue label, handwritten in black ink, handwriting unknown]// indicans [beige label, handwritten in black ink, handwriting unknown]// No 464/ examined by/ Prof. Thaxer for/ Laboulbeniaceae . [beige label, typed black ink, except for 464 handwritten in black ink]//” ( BMNH) .

Porrorhynchus brevirostris Régimbart, 1877 lectotype here designated (1 ♂ pinned, Fig. 16A ): “Ceylan [beige label, handwritten in black ink, handwriting unknown]// MUSEUM PARIS/ COLL MAURICE REGIMBART/ 1908 [beige label with thin black border, typed in black ink]// TYPE [red label, typed black ink]// LECTOTYPE [red label, typed black ink]” (1 ex. MNHN) . Paralectotype (1 ♀ pinned, missing right proleg after femur): “ Java [beige label, handwritten in black ink, handwriting unknown]// MUSEUM PARIS/ COLL MAURICE REGIMBART/ 1908 [beige label with thin black border, typed in black ink]// TYPE [red label, typed black ink]// PARALECTOTYPE [red label, typed black ink]” (1 ex. MNHN) .

Type Designations. The BMNH only possesses a single representative of material clearly examined by Walker for description of D. indicans . However, due to the possibility of other syntypes existing and no indication from Walker as to a singular specimen examined, we follow Recom- mendation 73F of ICZN (1999) and designate a lectotype for D. indicans Walker, 1858 , rather than regard it as the holotype. Régimbart’ s (1877a) original description of P. brevirostris indicates that there were three specimens used in the description, one from “ Ceylan ” stated as being from the Deyrolle collection and two from Java (in error) in the Jekel and Régimbart collection. Only two specimens could be located in the MNHN, one with the locality label of Java and the other with Ceylan, both indicated belonging to Régimbart’ s collection, now in the general collection of the MNHN. After searching for the other specimen in the MNHN, it is now presumed lost. Therefore, these two specimens are considered part of the syntype series, and the male specimen with the label “ Ceylan ” is here designated as the lectotype , as P. indicans is truly found in Sri Lanka. Given that Régimbart himself synonymized his own name, this designation seems quite sound. The specimen from Java is regarded as a paralectotype .

Régimbart (1877b) did again describe P. brevirostris as part of his work on the genera Enhydrus Laporte and Porrorhynchus . However, this description elaborated upon the previous one, at least the French portion, and had no indication of the taxon as being newly described. In this way, the 1877b description should be regarded as a redescription. Elsewhere, Régimbart did indeed describe the same taxon twice, indicating each time the taxon as being new (i.e., Dineutus cribratus in Régimbart 1886a, b); these names must be regarded as junior homonyms, requiring lectotype designations to ensure them as such, following the suggestion of Nilsson (2015). Fortunately, this is not the case with P. brevirostris , and no additional lectotype designation is necessary.

Additional Material Examined. SRI LANKA (" Ceylonia "): "Mus: Brents " (1 ex. ZMUC) ; " Ceylon ": (2 ex. BMNH) , Sharp Collection 1905- 313 (1 ex. BMNH) , "Mus./ Hauschild/ 12-9-1914 " (2 ex. ZMUC) , "Mus./ Westerm" (1 ex. ZMUC) ; "Niemer" (1 ex. BMNH) , "Niemer" "Fry Collection/ 1905-100" (1 ex. BMNH) ; leg. P. Brinck, ZML.2010/ 332 (1 ex. MZLU) , leg. Lewis, Sharp Collection 1905-313 (1 ex. BMNH) , leg. G. Lewis, ZML.2010/ 331 (1 ex. MZLU) , leg. G. Lewis, Sharp Collection 1905-313 (2 ex. BMNH) ; 1910, leg. G. Lewis, -320, (4 ex. BMNH) ; [illegible addition], " Coll.Mus. / Vindob. " (3 ex. NHMW) ; [illegible addition], l" M. Doh " [on label, unknown meaning], " Coll.Mus. / Vindob. " (1 ex. NHMW) ; Colombo: Sharp Collection 1905-313 (1 ex. BMNH) . No locality information: Sharp Collection 1905-313 (3 ex. BMNH) ; "Jekyl" (1 ex. BMNH) ; "6756" (1 ex. BMNH) .

Type Locality. Sri Lanka .

Diagnosis. Labrum ovoid and shorter relative to other Porrorhynchus species . Antenna with seven flagellomeres ( Fig. 2B ). Yellow lateral margins incomplete on elytra, extending normally only to the basal third ( Fig. 1C ). Elytral apices with blunt parasutural point, without spines ( Fig. 1C ).

Porrorhynchus indicans can be distinguished from all other species of Porrorhynchus by the incomplete yellow lateral margins of the elytra, as well as the elytral apices possessing large, triangular parasutural points, rather than spines.

Redescription. Size: ♂ L: 16.6 – 19.2 mm, W: 9.4–11.2 mm; ♀ L: 15.1–17.0 mm, W 8.2–9.5 mm. Habitus: Medium sized member of genus; body form elongate oval, attenuated anteriorly in male, female nearly parallel-sided in appearance; in lateral view, weakly convex, only slightly humped in scutellar region; in general, dorsoventrally depressed relative to other species. Coloration: Dorsally head, pronotum, and elytra olive green, pronotum and basal 1/3 of elytra with yellow lateral margins; venter yellowish to reddish orange, ultimate maxillary palpomere black, except for apex; fore legs often slightly darker in coloration, tibia black in proximal 1/2. Head: Vertex with sparse, weakly impressed punctures; orbital ridge without yellow margin, similarly colored as vertex; frons with weakly impressed punctures separated by 2–3X diameter of a puncture, fronto-lateral margins lightly wrinkled, frontoclypeal suture with posterior margin nearly straight, lateral margins nearly straight, meeting posterior margin at ca. 110° angle; clypeus with punctation most evident at anterior margin, punctures separated by ca. 2–3X diameter of a puncture; antennal flagellum with 7 flagellomeres ( Fig. 2B ); labrum ovoid, punctation nearly absent basomedially, strongly present apically, punctation well-impressed, dense, separated by 1.5–2.0X diameter of a puncture; maxillary/labial palpi ( Fig. 6M ) somewhat dissimilar in shape, maxillary palpi broader with asymmetrical dorsal/ventral margins, ventral margin more strongly curved than dorsal margin, labial palpi with anterior/posterior margins more similar, anterior margin nearly straight, posterior margin weakly curved. Thorax: Pronotum with shallow, weakly impressed wrinkles medially on disc, shallow transverse depression also often present medially, reticulation effaced on medial disc, weakly impressed, sparse punctation present, lateral reticulation well-impressed, punctation weakly impressed, nearly imperceptible, widely spaced, distance between nearest punctures up to 4–5X diameter of a puncture, lateral marginal depression present; protrochanteric setose patch situated apicolaterally; protibial spine projecting forward; male protarsi wide, dorsally convex, shape as in Fig. 6L , male ultimate protarsomere ca.>2X as long as wide; ultimate protarsomere of female ca. 2.5X length of penultimate; elytra with reticulation effaced in scutellar/sutural regions, reticulation present apically/laterally, most strongly impressed marginally, elytral disc with even covering of weakly impressed, fine punctation, distance between nearest punctures ca. 2–3X diameter of a puncture; lateral marginal depression narrow, of similar length throughout, yellow lateral margin incomplete, typically ending in basal 1/3, when longer never reaching epipleural angle, apicolateral margins of elytra without triangular sawtooth-like spines, elytral apices ( Fig. 1C ) not spinose, with parasutural points in form of broad triangle, created by lateral, obliquely truncate margin with rounded inner margin, sutural angle often produced; mesoventral apex not noticeably acuminate; meso- and metacoxae dissimilar, mesocoxae without posteriorly projecting process, mesocoxal process broadly rounded; male mesotarsal claws as in Fig. 6O , with ventral margin broadly rounded, anterior claw apically narrowed; metacoxal process as in Fig. 6M , with distinct apicolateral corners, weakly sinuate lateral margins. Genitalia: Aedeagus ( Fig. 5 ) with median lobe nearly as long as parameres, parallelsided for most of length, strongly acuminate in apical 1/5, apex broadly rounded in lateral view ( Fig. 5B ), briefly weakly curved dorsally; parameres in dorsal view laterally expanded in apical 1/3, rounded apically, medially reflexed basally; in lateral view, ventral margin of parameres evenly curved anteriorly to posteriorly. Female reproductive tract ( Fig. 13B ) with large, broad tubiform spermatheca; gonocoxae with lateral sinuation, apically acuminate.

Sexual Dimorphism. Females are smaller in size and much more parallel-sided in body form.

Distribution. This species is only known from Sri Lanka ( Fig. 14 ). Brinck (1980) found it to be primarily known from the southern central region of the island. For this study, almost none of the material had specific locality information, aside from the island of Sri Lanka. One specimen indicated it was collected from Colombo, See Brinck (1980) for more precise locality and distribution data.

Biology. Brinck (1980) demonstrated that P. indicans is restricted to intact (what he calls “primeval”) montane forest. After searching previ- ously known localities, Brinck (1980) was only able to re-collect the species from two streams in sheltered ravines within such forests at elevations above 1,200 m, with water temperatures below 20°C. Within the streams, the species was mainly found in regions sheltered from the main current ( Brinck 1980).

Discussion. Given the few known exact localities from Brinck (1980), the difficulty in re-collecting the species in 1980, and imperiled with future potential habitats loss, P. indicans is certainly warranting formal protection status. Future investigation into the distribution and status of this species on the island is highly desirable. We here propose the common name of the Sri Lankan snouted whirligig for P. indicans .

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. 5. Porrorhynchus indicans aedeagus. A) Dorsal view, B) Lateral view, C) Ventral view. Scale bar = 1 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. 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.