Macromia siamensis Makbun 2022, sp. nov.
Creators: name: Makbun, Noppadon
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Corduliidae
Macromia
Macromia siamensis

description: Macromia siamensis sp. nov.
(Figs. 1–11)
Holotype. 1 ♂, Thailand, Chiang Mai province, Chom Thong, Ban Luang (altitude 580 m), 13–iii–2015, N. Makbun leg.
Paratypes. 2 ♂♂, 14–iii–2013, locality, data and collector the same as for the holotype.
Etymology. The new species is named after Siamensis, a Thai non-profit organization, in recognition of their continued support for my work, and in honor of Siam, the former name of Thailand, the country in which the new taxon was found. Siamensis is a group of taxonomists in various fields and keen enthusiasts who contribute and give public awareness on biodiversity and the environment in Thailand. Also, ‘siamensis’ is a Latin adjective derived from Siam.
Description of holotype
Head (Figs. 1–3). Face black with yellow pattern. Compound eyes dark brown. Vertex with two pointed metallic black protuberances. Antenna black. Postfrons yellow with black upper margin and with a groove in the middle. Antefrons metallic black with yellow lower margin. Postclypeus wholly yellow. Anteclypeus black with both sides pale. Labrum and base of mandible black. Labium yellow with darkened upper part on the inner margin.
Thorax (Figs. 4–5). Prothorax black with yellow markings, as follows: middle lobe with lateral spot, posterior lobe entirely black. Synthorax black with iridescent blue reflection and covered with white setae. Antealar sinus yellow. Mesepisternum with broad, dorsally tapering antehumeral stripe and extended throughout its length, upper margin almost touching antealar sinus, lower margin running down across mesokatepisternum. Broad yellow lateral stripe cover metepisternum and metastigma except for upper and posterior margins. Posterior margin of metepimeron yellow, occupying about one fourth of its area. Poststernum is entire yellow. Leg black except for coxae largely yellow. Tibial keels yellowish.
Wings hyaline with dark veins (Fig. 7). Ax 13 on FW, 8 on HW. Px 6 (right), 7 (left) on FW, 8 (right), 10 (left) on HW. The anal angle of the wing rather rounded. Anal triangle with one crossvein. Anal loop 5-celled, without central cell. Two crossveins in cubital space. Discoidal field widening from one to ten cells in both wings. Triangles in both wings without crossvein. Supratriangles with 2 (right) –3 (left) cells in FW, and one cell in HW. Pt black.
Abdomen black with yellow markings (Figs. 8, 10) as follows: S1 with large anterolateral spot, S2 with basal ring covering auricle, S3 with large middorsal spot and anterolateral spot separated from each other, S4–6 each with a large basal ring, S7 with basal ring connected to irregular markings at some points. S8 with dorsal irregular triangle, and a ventrolateral spot extending to basal half. S9 with anterolateral spot. The posterior margin of S9 pointed when seen laterally. S10 entirely black, its dorsal outline slightly arched but do not form a protuberance.
Caudal appendages blackish brown, pale at the base, longer than S10 (Figs. 9, 11). Cerci slightly longer than paraprocts. In lateral view, cerci broad basally and slightly tapering to its apex, ventral margin of posterior half possesses small blunt spines. Their tips acute and pointing upward. Paraprocts curved, broadest at middle, with pointed apex, directed inward. In dorsal view, cerci slightly diverge from base and gently curved inward at their half-length, their outer margin furnished with lateral spines with tips pointing outward. Paraprocts triangle-shaped with a small hook pointing inward.
Secondary genitalia (Fig. 6). Vesicle triangle-shaped, covered densely with thick short setae. Posterior hamulus basally pale and dark apically, broad at base and distinctly tapered to its apex furnished with a hook on its posterior side and expanded on its anterior side, forming a hammer-like shape.
Measurements (in mm). HW 39.0, abdomen including anal appendages 45.0, total length (with head and anal appendages) 63.5
Variations in male paratypes. All paratype males are smaller than the holotype (HW: 36.8–37.8, abdomen including caudal appendages: 43.5–45.9, total length: 61.1–63.0). One specimen has a pale spot in middle of the anteclypeus. One specimen with two cells in triangle on left HW. Ax with 13 in FW and 7–8 in HW, Px with 5–7 in FW and 7–10 in HW. Cubital crossveins 4–5 on FW and 3 on HW. Supratriangle with 1–2 crossveins on FW.
Female. Unknown
Differential diagnosis. The new species is easily separated from all Macromia species so far known from Thailand by the antehumeral stripe reaching the antealar sinus. So far, this long and broad stripe is unique among the species in the Indomalayan realm reported in Laidlaw (1922), Fraser (1924, 1936), Lieftinck (1929, 1955, 1971), Muraki (2009, 2010, 2014, 2015, 2017), Yokoi & Souphanthong (2014, 2019), Sumanapala (2021). Furthermore, there are two ‘ Macromia sp. ’ species from Chiang Mai province listed in the book “Atlas of the dragonflies of Thailand – distribution maps by provinces” (Hämäläinen & Pinratana 1999, p. 95). One of those species is probably M. siamensis.
Using the diagnostic characters and distribution records of the Macromia species in Asia in Lieftinck (1955), Asahina (1968), Vick (1988), Zhou et al. (1994), Karube (2020), Wilson (2020), M. siamensis is found to be closest to the following congeners: M. amphigena Selys, 1871 from Kazakhstan, Russia, China, Mongolia, Japan, North Korea and South Korea, M. sombui Vick, 1988 from Nepal, M. cydippe Laidlaw, 1922 from Indonesia, Malaysia and Thailand, M. vangviengensis Yokoi et Mitamura, 2002 from Thailand and Laos, M. clio Ris, 1916 from China, Taiwan, and Japan, and also M. malleifera Lieftinck, 1955, and M. macula Zhou, Wang, Shuai & Liu, 1994 from China.All these species share the hammer-shaped tip of posterior hamulus. However, M. siamensis can be separated from all of these by a combination of characters: a broad antehumeral stripe reaching antealar sinus (a short and narrower stripe in M. amphigena, M. clio, M. macula, M. sombui; absent in M. malleifera, M. vangviengensis), postfrons yellow with black upper margin (dark brown to black with green/blue iridescent reflection in M. amphigena, M. clio, M. cydippe, M. malleifera, M. sombui; black with blue iridescent reflection with two small yellow spots in M. macula; dark brown in M. vangviengensis), S10 without distinct protuberance (the same in M. macula; a strongly raised protuberance with pointed apex in M. sombui, M. malleifera, M. vangviengensis; a strongly raised protuberance with blunt apex in M. clio, M. cydippe; absent in M. amphigena), S4–6 with a large basal ring (S3–6 with dorsal spots in M. amphigena, M. clio, M. macula, M. malleifera, M. sombui; S3–5 with dorsal spots in M. vangviengensis; S3–6 unmarked in M. cydippe), postclypeus entirely yellow (the same in M. amphigena, M. clio, M. macula; yellow with dark brown lower margin in M. malleifera, M. vangviengensis; entirely dark brown in M. cydippe; dark brown with wedge-shape spots in M. sombui).
Habitat and Ecology. Macromia siamensis was found patrolling above a shallow and small stream in an open area at 580 meters above sea level (Figs. 12–13). I found this species a few times and only one or two males were encountered each time. M. flavocolorata and M. chaiyaphumensis are also present in this stream but at different periods in a year. Other interesting species found at this stream were Microgomphus farrelli Makbun & Fleck, 2018, Lamelligomphus sp., Nihonogomphus pulcherrimus (Fraser, 1927), Stylogomphus sp., Phaenandrogomphus tokinicus (Fraser, 1926), Philoganga montana (Hagen in Selys, 1859), and Prodasineura doisuthepensis Hoess, 2007.
Distribution. To date, it is only known from the type locality, Chiang Mai province, North Thailand (Fig. 14).
description: Published as part of Makbun, Noppadon, 2022, Macromia siamensis, a new species from North Thailand (Odonata: Anisoptera Macromiidae), pp. 346-354 in Zootaxa 5133 (3) on pages 348-352, DOI: 10.11646/zootaxa.5133.3.2, http://zenodo.org/record/6522526