Ceylonosticta venusta Bedjanič & Conniff, 2016

Tol, Van, 2016, Taxonomy and molecular phylogeny of the Platystictidae of Sri Lanka (Insecta: Odonata), Zootaxa 4182 (1), pp. 1-80 : 28-31

12. Ceylonosticta venusta Bedjanič & Conniff sp. nov.

Figs. 63−69 , 151−153 ; Map 5.

Drepanosticta sp. nov. B—Bedjanič et al. (2014): 139 [differential characters, biology, distribution, Ƌ photograph]. SPECIES DIAGNOSIS IN THE KEY → 6b; NUMBER OF KNOWN LOCALITIES— Bedjanič et al. (2014): 6.

Type material. Holotype: 1Ƌ (mature male, ex alcohol), Rambodde Falls, at the tunnel; Nuwara Eliya District , Central Province; N7.0489, E80.6961; alt. 920m; 12-vii-2012; M. Bedjanič leg (to be deposited in CNMS) ; Paratypes: 1♀ (mature female, ex alcohol, to be deposited in CNMS), locality data the same as for holotype; 1Ƌ (in alcohol), locality data the same as for holotype (to be deposited in RMNH).

Etymology. The species epithet, a Latin adjective, signifies the charming coloration and beauty of the species.

Diagnosis. Medium to small-sized Ceylonosticta , belonging to C. austeni group of species. The uniformly rusty-brown dorsum of the thorax of both sexes is a character shared only with C. brincki , while C. austeni , C. digna and C. nietneri all have a blue or greenish-blue middorsal stripe on the synthorax. Slightly bigger and more robust than C. brincki , synthorax in mature individuals of both sexes brown above the lateral blue thoracic stripe and golden yellow below, while in C. brincki sides of thorax brown above and below the lateral blue thoracic stripe. Males are distinguished at a glance from C. brincki based on the shape and equal length of superior and inferior anal appendages. Inferiors are apically prolonged, with conspicuous subapical inward and slightly caudally directed spine, very similar to C. austeni but longer and more conical. A somewhat similar subapical spine also present in C. digna , but much shorter inferiors of the latter separate these two species at a glance. In C. brincki the conspicuous subapical inwardly directed spine is lacking. Apart from lateral thoracic coloration, female of C. venusta sp. nov. is distinguished from C. brincki by posterior margin of posterior prothoracic lobe not evenly rounded but with marked rounded dorsolateral expansions and by the dorsal sky-blue coloration of last abdominal segments obscured proximally.

Description of holotype male [dried specimen ex alcohol]. Head.—Labium light brown, bases of mandibles dark brown, with light brown dorsolateral portions towards labrum and anteclypeus. Labrum and anteclypeus whitish blue, anterior part of labrum brown, with rather long brown setae. Genae black, as is postclypeus and frons. Anterior border of postclypeus with few long light brown setae. Vertex, occiput and epicranium glossy black. Occiput behind ocelli with row of three to four closely situated light setae on each side of middle and single seta at level of acute edges of well-developed transverse postoccipital ridge. Bases of antennae dark brown, scapus and pedicellus ochreous, flagellum dark brown ( Fig. 63 ). Rear of head black. Eyes in preserved specimen brown.

Thorax. —Prothorax light ochreous on sides, darker brown to grey dorsally, with light bluish tint. Anterior lobe with elevated, upturned thickened anterior margin, which is black apically. Posterior lobe of prothorax with posterior margin dark brown and gently upturned, evenly rounded ( Figs. 63–64 ). Dorsum of synthorax dark brown and of same colour laterally until metepisternum. Metepimeron light ochreous. Lateral blue stripe poorly defined and obsolete due to preservation ( Fig. 63 ). Under surface of thorax uniformly light ochreous. Legs light brown, tibiae slightly darker.

Wings.—Wings clear, venation dark brown ( Fig. 69 ). Left forewings with 15½ and hindwings with 14½ Px, right forewings with 16 and hindwings with 14½ Px. Arculus distal to Ax2, R4+5 at level of subnodus. IR3 separates from R4+5 at level of first crossvein distal to arculus. Y vein stalked. CuP reaching hind margin of forewing at level of Px 4, in hindwing at level of Px 4 − 5. Number of cells between Arc and place where CuP meets hind margin of hindwing 9. Pterostigma brown, encircled by narrow lighter line and surrounded by thick dark brown veins, proximal side oblique, distal side slightly convex, more than two times wider than high.

Abdomen.—Slender, dark brown dorsally and laterally. Anterior half of S1 ochreous ventrolaterally, S2 with basal triangular lateral ochreous marking pointed posteriorly and nearly reaching segment end. S3–7 basally with light brown rings which are largely obscured on dorsum and broadest on S3–6. From base of segments they are narrowly prolonged ventrally to almost end of segments. Dorsum of S10 and S9 light blue as is narrow intersegmental membrane between S9 and S8, the latter completely dark brown on dorsum ( Fig. 65 ). Anal appendages dark brown, apical portions of inner side of superiors and inner side of inferiors light brown. Superior and inferior appendages of same length, almost twice as long as S10. Superiors with strong base, evenly curved medially, touching at apices. Apical halves laterally flattened and bent downwards. Inferiors with expanded basal third, which has small projection medially, then narrowed, laterally flattened and apically prolonged. Middle of narrower portion abruptly broadened ventrally in form of conspicuous sharply triangular inward- and slightly backwards-directed spine ( Figs. 65–66 ).

Measurements [in mm]. Ƌ—head width: 3.8; abdomen length: 36.2; fore- and hindwing length: 24.3, 24.4; fore- and hindwing pterostigma length: 1.24, 1.14; superior appendages: 0.8.

Description of paratype female [dried specimen ex alcohol]. General habitus similar to male ( Fig. 67 ). Venation as in male. Left forewings with 15½ and right forewings with 16 Px. Both hindwings with 14½ Px. Prothorax greyish blue on dorsum, light ochreous on its sides. Anterior lobe dark brown, upturned, plaited and thickened. Posterior lobe of prothorax with posterior margin brownish and upturned, slightly saddle-shaped medially, with marked dorsolateral expansions on each side ( Fig. 68 ). Vertex of synthorax dark brown, rest of thorax below obscure greyish-blue thoracic band (due to preservation) of markedly lighter brown colour laterally and ventrally. Abdomen brown, dark brown dorsally, S3–7 with short basal bluish-grey marking on dorsum, lateral and ventral of which the coloration changes to light ochreous patches, which are prolonged and narrowed caudally. Dorsum of S9–10 light blue, as is intersegmental membrane between S9 and S8 and extremely narrow posterior margin of S8. Cerci dark brown. Ovipositor reaching tip of cerci with styli exceeding them in length.

Measurements [in mm]. ♀ —head width: 3.9; abdomen length: 31.3; fore- and hindwing length: 22.9, 22.8; fore- and hindwing pterostigma length: 1.18; ovipositor: 2.4.

Remarks. Coloration in life.—Eyes of both sexes in life bluish grey dorsally, with broad median rusty-brown band and light ochreous ventral portions. Middle lobe of prothorax sky blue on dorsum, posterior portion of posterior prothoracic lobe dark brownish, largely obscuring blue colour in some animals. Dorsum of synthorax dark brown, antealar triangles brown, posterior alar processes with a small patch of blue. Lateral blue band framed narrowly with dark brown also below as far as metapleural suture, but metepimeron of contrasting golden-yellow coloration. Abdomen very dark brown on dorsum, except for ochreous basal portions in males and blue basal portions in females. In the latter, the blue coloration on S9 as well as on intersegmental membrane between S9 and S8 is markedly obscured with very dark brown proximally ( Figs. 151–153 ). Molecular analysis.—Type material was collected and stored in alcohol, and two legs of paratype male in alcohol were deposited at RMNH where molecular analyses were performed. Habitat.— C. venusta sp. nov. has been observed and photographed at only a few localities in the wider surroundings of Rambodde in central part of Sri Lanka. Its distribution is obviously limited to higher altitudes between 700 and 1,000 metres, although it has also been recorded as high as over 1,600 metres. It also seems to be very seasonal, as all records so far originate exclusively from July. Searches for the species in November have been unsuccessful at the known localities. Conservation.—Preserved natural forest habitats with small streams and seepages in the central mountainous part of Sri Lanka are very scarce and highly fragmented. Water from them is extracted for consumption and irrigation, and remaining forest patches are converted to home gardens and domestic tea plantations. Therefore, the endemic C. venusta sp. nov. is globally threatened, and it definitely deserves immediate conservation attention, together with the majority of its endemic relatives.

Faunistic records [localities listed north to south]. —(1) Talawantenne, stream at the road to Pundaluoya, 1.8km SW of Talawantenne junction ; Nuwara Eliya District , Central Province; N7.0537, E80.6765; alt. 785m; 12- vii-2012; M. Bedjanič; 1Ƌ.—(2) Rambodde, stream at the road Rambodde-Sangilipalama, 1.7km NW of Rambodda tunel ; Nuwara Eliya District , Central Province; N7.0613, E80.6845; alt. 820m; 12-vii-2012; M. Bedjanič; 1Ƌ.—(3) Rambodde, stream at the road Rambodde-Sangilipalama, 1.4km NW of Rambodde tunnel ; Nuwara Eliya District, Central Province; N7.0604, E80.6874; alt. 840m; 12-vii-2012; M. Bedjanič; 1♀.—(4) Rambodde Falls , at the tunnel ; Nuwara Eliya District, Central Province; N7.0489, E80.6961; alt. 920m; 12-vii- 2012; M. Bedjanič; 1♀, 2Ƌ.—(5) Rambodde, stream at the road near quarry, 800m S of Rambodde tunnel ; Nuwara Eliya District , Central Province; N7.0491, E80.6997; alt. 1040m; 11-vii-2012; M. Bedjanič; 1♀.—(6) Nuwara Eliya, stream in eucalyptus forest on the old road Pundaluoya-Nuwara Eliya, 7km NW of Nuwara Eliya ; Nuwara Eliya District , Central Province; N6.9969, E80.7143; alt. 1640m; 15-vii-2012; M. Bedjanič; 1♀.

Figures

FIGURES 63 – 69. Ceylonosticta venusta sp. nov. — (63) thorax and head, lateral view [male, holotype]; (64) prothorax, lateral view [male, holotype]; (65) anal appendages, dorsal view [male, holotype]; (66) anal appendages, ventral view [male, holotype]; (67) thorax and head, lateral view [female, paratype]; (68) prothorax, lateral view [female, paratype]; (69) wings [male, holotype]. [Material origin: male holotype and female paratype—Rambodde, Nuwara Eliya District, Sri Lanka]

FIGURES 144 – 151. Coloration in life: Ceylonosticta austeni — (144) male, (145) female; Ceylonosticta brincki — (146) male, (147) female; Ceylonosticta nietneri — (148) male, (149) female; Ceylonosticta digna — (150) male; Ceylonosticta venusta sp. nov. — (151) male [photos: M. Bedjanič, fig. 150 photo: K. Conniff].