A new species of Ceylonosticta Fraser, 1931 (Odonata: Zygoptera: Platystictidae) from Sri Lanka

A new species of Ceylonosticta from the wet zone of Sri Lanka is described and illustrated, namely Ceylonosticta goodalei sp. nov. (Kuruwita-Erathana foot path, Seethagangula, Adam’s Peak, Samanala Nature Reserve, Ratnapura, 6.8196°N, 80.4615°E, 1109 m asl). The species is described from male specimens only and the genital ligula is described and illustrated. Females are as yet unknown. A brief review of Ceylonosticta “species-groups” is provided, provisionally incorporating three recently described species (C. nancyae, C. rupasinghe, C. alwisi) as well as C. goodalei. A determination key is updated by addition of these four newly described Ceylonosticta species and now covers 22 endemic species of the genus hereto known from the island. http://www.zoobank.org/urn:lsid:zoobank.org:pub:3A443B9F-CAD0-42AE-A4C1-8476C83DF8E9

The genus Ceylonosticta was originally differentiated from the genus Drepanosticta on the basis of the male having a dorsal ridge on the penal organ as both genera have very similar wing venation (Fraser, 1931a(Fraser, , 1931b. However, the genus Ceylonosticta was subsequently treated as a synonym of Drepanosticta by later authors (Bedjanič, 2010(Bedjanič, , 2012Bedjanič et al., 2014;Lieftinck, 1940Lieftinck, , 1955Lieftinck, , 1971van der Poorten & Conniff, 2012). Recent studies using phylogenetic and morphological information have shown that the Sri Lankan Platystictids are monophyletic, indicating that Ceylonosticta is a distinct genus and not congeneric with Drepanosticta (which has no representatives in Sri Lanka) (Bedjanič et al., 2016;Dijkstra et al., 2014). It was also shown that the genus Platysticta is endemic to Sri Lanka, as Platysticta deccanensis Laidlaw, 1915 from India belongs to another clade and has been accordingly transferred to a new genus, Indosticta (Bedjanič et al., 2016).

Materials and methods
Field observations were made in two different locations within Ratnapura district, Sabaragamuwa province which are classified as belonging to the wet zone of Sri Lanka (Figure 1). Both primary literature (Bedjanič, 2010;Bedjanič et al., 2016;Fraser, 1931aFraser, , 1931bFraser, , 1933aFraser, , 1933bPriyadarshana et al., 2016) and secondary literature (Bedjanič et al., 2014) were used to identify the specimens. Descriptive terminology and descriptions of wing venation follow Watson and O'Farrell (1991). Measurements are given in millimeters (mm). Except for the anal appendages, all coloration is given as detectable from live specimens. Supplemented photographs of the adult live specimens were taken with a Canon EOS 600D (Tokyo, Japan) camera body fitted with a Canon 18 _ 55 mm lens. Photographs of the anal appendages and the preserved specimens (only males) were taken using Nikon Cool pix L120 (Tokyo, Japan) camera fitted onto a Leica DM2000 light microscope (Wetzlar, Germany). All illustrations were done by hand with the aid of a Leica DM2000 light microscope. The type specimens have been deposited in the research laboratory of the National Wildlife Research and Training Center (NWRTC), Giritale, Sri Lanka (voucher numbers: 019TIBSJ __ 021TIBSJ). Leg tissues and two of the adult male specimens were preserved in 100% ethanol for future molecular analyses. The key given by Bedjanič et al. (2016) for identifying Ceylonosticta species is modified by adding the three recently described new Ceylonosticta species (Priyadarshana et al., 2016) and the new species described here.

Etymology
The species epithet is an eponym Latinized in the genitive singular, honoring Prof. Eben Goodale, ornithologist, from College of Forestry, Guangxi University, China. He has studied mixed-species bird flocks in Sinharaja World Heritage Site in Sri Lanka.

Description of holotype
Head. Labium brown; labrum, anteclypeus and genae pale blue; mandible glossy black. Frons slightly convex, metallic black below ocelli and antennae. Both dorsal and lateral ocellus Thorax. Prothorax laterally pale yellow, dorsum of anterior lobe largely blue with blackishbrown anterior border, middle lobe is blue on dorsum which comprises a triangular-shaped central blue spot and a single round blue spot on either side, and lateral surface is yellowish, posterior lobe sky blue with narrow blackish-brown posterior border ( Figure 2D, E). Mesepisternum chocolate-brown. Mesepimeron brown. Metepisternum with a sky-blue stripe, slightly broader posteriorly. Metepimeron pale brown ( Figure 2C). The ventral side of thorax pale yellow.
Wings. Hyaline. Pterostigma blackish-brown covering one cell. Fw two antenodals, 15½ postnodals; Hw two antenodals, 14½ postnodals. CuP reaching posterior margin of forewing approximately at level of Px5, in hind wing approximately at level of Px6. R 4+5 distal to subnodus, then IR3 arising from distal R 4+5 . Number of cells between Arc and place where CuP meets hind margin of hind wing 8.5. Sectors of arc arise from a common stalk. Ab incomplete ( Figure 2F).
Abdomen. Slender. Dorsum blackish-brown, laterally pale brown, ventral surface pale yellow. S3-S8 and S10 with narrow sky blue dorsal basal markings which do not meet ventrally, markings on S4-S7 more prominent, a minute dorsal apical blue marking also on S8, sky blue on the dorsum of S9.
Anal appendages (dried specimen). Dark brown. Cerci hairy, in dorsal view broadly curving inwards and downwardly twisted near the distal one-fourth, in ventral view gradually curving downwards, distal end broadly rounded, slightly longer than paraprocts. Paraprocts with minute hairs, broad at base, in two planes with the outer plane depressed in dorsal view, then tapering to a broad point, a blunt inwardly pointing spine two-thirds of the way to the tip ( Figure 2G-I).
Genital ligula. Curled over and embracing the stem of the organ which is ellipsoidal in shape, another branch spreads outwards from the stem. Possesses a ridge on its dorsum; the ridge is broad at base, cone-shaped and blunt at apex ( Figure 3J).
Variations in males. Paratype males did not show significant variation from the holotype.

Differential diagnosis
Medium-sized. Prothorax with anterior lobe mostly blue, dorsum of the median lobe blue and yellowish on the sides, and posterior lobe sky blue with narrow blackish-brown posterior border. Synthorax chocolate-brown on dorsum. Abdomen chocolate-brown with narrow blue dorsal basal markings on S2-S8 and S10, also a minute dorsal apical blue marking on S8, sky blue on the dorsum of S9. Cerci slightly longer than paraprocts and downwardly twisted near the distal one-fourth and broadly rounded at the end. Paraprocts in two different planes with the outer plane depressed (in dorsal view), narrow with a blunt inwardly pointing spine two-thirds to the tip.
C. goodalei sp. nov. belongs to the C. austeni-species group sensu Bedjanič et al. (2016). Males of C. digna Hagen, 1860, C. nietneri Fraser, 1931, andC. austeni Lieftinck, 1940 can be readily distinguished from the new species because they all have a sky-blue stripe on the dorsum of the synthorax. C. brincki Lieftinck, 1971 andC. venusta Bedjanič &Conniff, 2016 are uniform rusty-brown on the dorsum of the synthorax, as is C. goodalei, and are distinguished by the shape of the paraprocts in the male. The paraprocts of C. brincki are without a conspicuous subapical inwardly directed spine and are apically widened, and hollowed out interiorly, with crescent shaped emargination. Those of C. venusta have a conspicuous, sharp, subapical, inward-and slightly backward-directed spine.
The species was observed inside a well-shaded typical wet-zone forest, near to the Kuru Ganga (Kuru River). Both sides of the river are densely vegetated with species of Elaeocarpus, Dipterocarpus and Michelia, and various typical wet-zone shrubs ( Figure 3A, B).

A brief review of Ceylonosticta species-groups
The grouping of members of the Ceylonosticta has been attempted twice. Fraser (1933b) provisionally grouped the 10 species known at the time into two groups based on venation: Group I included the species in which vein R 4+5 arises proximal to the vein descending from the node, and Group II included those in which vein R 4+5 arises at or a little distal to the vein descending from the node. Bedjanič et al. (2016) assigned the 18 known species into seven "species-groups", viz., anamia, adami, austeni, bine, hilaris, mojca, and montana, based on morphological and molecular analyses.
Three recently described species were not included in these assignments: does not belong to any of these species-groups based on morphological characters, and molecular analyses are needed to clarify the proper placement of this species within the species-groups. Ceylonosticta alwisi can be placed within the mojca group based on the conspicuous stalked dorsal processes on the anterior lobe of the prothorax. Ceylonosticta rupasinghe does not fit clearly into any of the defined species-groups, but it could belong to the anamia group based on the following characters: its general appearance, the vein R4 + 5 arising well proximal of the crossvein descending from the node in both wings, the orange-yellowish middle lobe of the prothorax in mature individuals, the number of the forewing Px (more than 16) and the shape of the paraprocts. Molecular analyses are needed to confirm this placement.
The austeni-group, to which C. goodalei has been assigned, now consists of six species and is the most speciose group among endemic Sri Lankan Platystictids. C. goodalei appears to be closely related to C. brincki and C. venusta, but molecular work is needed to further elucidate the relationships within this interesting group of species.

Addendum to the key to Ceylonosticta species
Note: This key is modified from Bedjanič et al. (2016) by adding species described since then (Priyadarshana et al., 2016;and the present article). As the comprehensive determination key of Bedjanič et al. (2016) covers 18 Ceylonosticta species and is accompanied by over 150 figures and distribution maps for all species, the goal of the present addendum is to incorporate four new species descriptions, those of C. alwisi, C. rupasinghe, C. nancyae and C. goodalei, so that the original structure and numbering in the key are retained. In doing so, the dichotomous structure of the key has been expanded where appropriate to trichotomous. For these four species, the appropriate reference, citing figures from the original article, is given.

Ceylonosticta goodalei Priyadarshana & Wijewardhane
Key of Bedjanič et al. (2016) 6a. Superior anal appendages of males longer than inferiors, the latter apically widened, hollowed out interiorly, with crescent-shaped emargination and without conspicuous subapical inwardly directed spine. In males, apical sky-blue markings on S8-S10. In females, posterior margin of posterior prothoracic lobe evenly rounded, last two abdominal segments sky-blue on dorsum. Synthorax in mature individuals of both sexes brown above and below lateral blue stripe; Superior and inferior anal appendages of males equal in length, the latter apically prolonged, with conspicuous subapical inward-and slightly backward-directed spine. In males, apical sky-blue markings only on S9-S10, including narrow intersegmental membrane between S9 and S8. In females, posterior margin of posterior prothoracic lobe with marked rounded dorsolateral expansions, the last abdominal segment sky-blue on dorsum, while on S9 the blue coloration is obscured proximally. Synthorax in mature individuals of both sexes brown above the lateral blue stripe and golden yellow below; ♂ [mm]: Hw 24. [NEW] Px in forewing > 16, large species. Anterior lobe of prothorax with pronounced blackish-brown posterior collar, middle lobe orange-yellow, posterior lobe blackish-brown with conspicuous flattened projections on each side that are twisted at the base. Genae yellow. Superior anal appendages broad and curve inwards, blunt at the distal end. Inferior anal appendages broad at base and bifurcated, with an axe-head