Sarasaeschna kaoi, Yeh, Wen-Chi, Lee, I-Lung & Wong, Kwok-Ching, 2015

Yeh, Wen-Chi, Lee, I-Lung & Wong, Kwok-Ching, 2015, Description of Sarasaeschna kaoi sp. nov. in Taiwan, with notes on the proposed differentiating characters of the pyanan - group (Odonata, Aeshnidae), Zootaxa 3926 (1), pp. 122-128 : 123-126

Sarasaeschna kaoi sp. nov.

Figures 1–13

Material examined. All type specimens were collected by IL Lee from Matailin Swamp (1050 m) in Yuli, Hualien County, Taiwan. Holotype: ♂, 03-VII-2013; Paratype: 1♀, 23-VI-2013; 3♂, 25-VI-2013; 2♂, 03-VII-2013. Holotype, female paratype and one male paratype (25-VI-2013) were deposited at Forest Arthropoda Collection of Taiwan ( FACT) in TFRI. Two male paratypes (1♂, 25-VI-2013 and 1♂, 03-VII-2013) and one male paratype (1♂, 03-VII-2013) to be transferred to National Museum of Natural Science in Taichung City and NDHU, respectively.

Etymology. The new species is named to memorize Mr. Yui-Ching Kao who passed away untimely in 2010 during field work. He was an approved and talented researcher in TFRI specialized in the ecology of aquatic plants and fishes, and he kindly encouraged and guided IL Lee during Lee’s stay at his laboratory.

Diagnosis. T-mark of postfrons with broad longitudinal stalk as wide as vertex; dorsal stripes of pterothorax widely separated for upper spots by at least 1/2 width of vertex; S4–7 with well-developed AML spots. Male has shorter cerci than its congeners, with length only 1.2 times as long as S10. Penis with flagella strongly twisted midway and recurved at apical 1/3, making apical part of the flagella adjoin the ventral margin of APS. Female with reduced yellow lateral markings in S2 as described.

Male (holotype, Figs. 1 & 2). HEAD: Labium dark brown with median lobe yellowish at base; mandible dark brown with a yellow spot at base; labrum dark brown, laterally with paired large rectangular yellow spots; anteclypeus dark brown; postclypeus yellow, lower margin with paired slim indentations dark brown. Antefrons black with upper 3/5 wrinkled, upper margin straight and weakly ridged, lower 1/4 yellow (Fig. 6); postfrons weakly depressed medially, with black T-mark and paired transverse yellow spots, longitudinal stalk of T-mark as wide as vertex (Fig. 7). Antenna black. Vertex about 1/3 width of frons, tumid, with paired small yellow spots anterodorsally. Occiput small and black. Compound eyes dull green, median seam a little shorter than width of vertex. Black hairs scattered on entire face and head, absent on wrinkled part of antefrons, longer and denser on postfrons, vertex and occiput.

PTEROTHORAX: Black, with yellow and pale green markings, front covered with long and dense brown hairs. Dorsal stripes short and bar-shaped, diverging downward from each other and obtuse at both ends, separated from upper oval spots by 1/2 width of vertex (Fig. 7). Yellow stripes of mesepimeron round at both ends, broader and adjoining humeral suture in lower half; metepisternum with an upper spot and a tiny speck located at mid point between upper spot and metahoracic spiracle; metepimeron yellow in posterior 3/4; mesinfraepisternum yellow, metinfraepisternum with a yellow triangular spot in posterior half.

LEGS: black, outer side of fore and hind coxae with small yellow spots; apex of hind femur reaching well beyond posterior margin of S1.

WINGS: Hyaline, yellow brown at basal extremities, veins black. Pterostigma dark brown, braced in all wings and underlain by 2.0–2.5 cells. Two rows of cell between MA and Mspl in both wings. Triangles four–celled (three-celled in right forewing), hypertriangles and subtriangles free. Numbers of costal crossveins 9:20:19: 9 in forewings and 11:12:12: 11 in hindwings.

ABDOMEN: Black with yellow or pale green markings. S1 and S2 swollen, as broad as synthorax, S3 moderately constricted at middle. Abdomen less expanded at middle than in S. chiangchinlii , weakly spindleshaped from apical half of S3 to S7, nearly straight in S8–10. S1 unmarked, laterally with a faint spot. S2 dorsally with round AD spot, paired teardrop-like MD spots and paired round PD spots (Fig. 3), and laterally with subsquare AL spot covering auricle, tiny PL spot above and irregular spot at posterolateral corner. S3–6 with paired and closely adjoining triangular PD spots, distinctly smaller on S6; S3 & S4 with paired tiny MD spot. Laterally, S3 with triangular AL spot, S4–7 with transverse AML spot, distinctly smaller on S7. S4–S7 with paired rectangular spots covering basal 1/3 of each sternite, smaller on S7. S8–10 unmarked, base of sternite 8 pale. S8 comparatively stouter than in other Taiwanese congeners. Auricle moderately developed and sub-triangular, protruding backward and armed with numerous dark denticles on posterior margin. Middorsal carina well discernible on S4–7, weakly developed in apical half of S3. Male cerci about 1.2 times as long as S10, short and slender, with apical 1/5 weakly dilated, apex roundly blunt ( Fig. 9 ). Cerci in lateral view gently curved dorsally, and widely and shallowly emarginate ventrally between subbasal and subapical teeth ( Fig. 8 ). Epiproct elongate and as long as cerci, deeply emarginate at apex with two prongs strongly diverging ( Fig. 10 ); ratio of depth to width of apical emargination about 1:2; apex of epiproct with stout teeth protruding upward in lateral view.

FIGURES 1–7. Sarasaeschna kaoi , 1–3, 6 & 7, holotype male, 4 & 5, paratype female. 1, dorsal; 2, lateral; 3 & 4, S2, dorsal; 5, abdomen, dorsal; 6, head in front view; 7, head and pterothorax, dorsal.

PENILE STRUCTURES: Configuration of penis similar to the other species of the pyanan -group. Flagella flat and extending perpendicularly to APS in basal half, strongly twisted from midlength and recurved in apical 1/3, apical part adjoining to ventral margin of APS. Ventrobasal sclerotized plates (dorsoventral processes in von Ellenrieder 2002) of APS well developed, elongate and crest-shaped in lateral view, basal part protruding anteroventrally ( Figs. 11 & 12 ).

Female (Paratype): General appearance of female similar to holotype male, differences noted as follows. Paired basal spots on labrum diminished as small transverse stripes; lower margin of postclypeus narrowly brownish. Abdomen shaped as in holotype male, black, S1 and S2 dark brown. S1 with small round AD and teardrop-like PD spots, laterally covered almost entirely by large irregular yellowish patch. S2 with MD spots boomerang-shaped (Fig. 4), AL spots transversely elongate and notched at upper margin, on the left slightly separated from, on the right connected to, square PL spots to form transverse band. S3 with AD spot reduced to tiny speck, S3–6 with paired small MD spots (Fig. 5). Cerci blade-shaped and short, only a little longer than S10 ( Fig. 13 ). Posterior margin of S10 protruding posteroventrally into dentigerous plate and armed with numerous closely-set and pointed spinules.

Variations in male paratypes: No significant variations were found in the five male paratypes. However, there were minor differences noticed. One male has a tiny dorsal spot on S1, but MD spots on S4 are almost undetectable; two males have paired MD spots on S3–5; AL spots on S1 are small or tiny in all five paratypes. Crossvein numbers 8:17–18:17–18: 7 in costal field of forewings and 9–10:10–12:12–13:11 of hindwings. Triangles three- or four-celled.

Measurements (mm). Holotype ♂: abd.+cerci 48, hindwing 41, pterostigma (forewing:hindwing) 4.0:3.5; Paratypes: ♂ abd.+cerci 45–49, hindwing 41–43, pterostigma 3.3–4.0:3.0–3.5; ♀ abd. (ex. cerci) 49, hindwing 44, pterostigma 4.0: 3.5.

Habitat and behaviour. So far, S. kaoi has been recorded only from the type locality Matailin Swamp in Yuli, Hualien County. The swamp is located at a depression 1050 m above sea level and adjacent to a mountain ridge belonging to the Coastal Mountain Range in the eastern coast of the island. The swamp was muddy and densely grassy, surrounded mainly by undisturbed evergreen forest ( Fig. 14 ). A small shallow water flowed through the swamp along one side. In Matailin Swamp the males of S. kaoi were observed to guard and patrol their territories exclusively on sunny days at shaded forest margins, while the males of S. lieni usually do this at adjacent open and grassy sites even on cloudy days. This scenario is the same as found in Tsaopi, Yilan County, where S. tsaopiensis is instead the shade guardian. The territories of male S. kaoi were over thick muddy ground covered by fallen leaves and organic detritus, a microhabitat similar to that found in Tsaopi for S. tsaopiensis (personal observation). The paratype female was observed before capture to oviposit on the ground. The activity period of adult S. kaoi in Matailin Swamp was very short, lasting for less than one month from late June to early July, while S. lieni dominated in numbers from middle May to middle June, and its numbers decreased later in June. It seems that the adults of S. kaoi and S. lieni not only differed from each other in microhabitat selection but to some extent also in flight season.

Figures

FIGURES 14. Overview of Matailin Swamp in Yuli, Hualien County.

FIGURES 8 – 13. Genital characters of S. kaoi. 8, male anal appendages, lateral; 9, do, dorsal; 10, male epiproct, ventral; 11, penis, ventral; 12, do, lateral; 13, female cerci, lateral.