Agriocnemis minima Selys 1877
Creators: name: Saetung, Tosaphol
name: Boonsoong, Boonsatien
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Coenagrionidae
Agriocnemis
Agriocnemis minima

description: Agriocnemis minima Selys, 1877
Figs. 3, 6, 9–37, 42–43, 46, 56, 61, 74–75
Agriocnemis minima Selys (1877): 50 [Holotype male, Java] Specimens examined. THAILAND, 4 reared specimens: 1 ♂ and 1 ♀, 12/III/2017, Kasetsart University (13°50′59″ N 100°34′26″ E, altitude 4.48 m), Bangkok province, T. Saetung leg.; 1 ♂ and 1 ♀, 28/IV/2018, Ban Na district (14°16′41′′ N, 101°00′57′′ E, altitude 8.6 m), Nakhon Nayok province, T. Saetung leg.; 10 last stadium larvae: 1 ♂, 22/ V /2017, Khon Kean University (16 o 27′47.6′′ N, 102 o 48′33.5′′ E, altitude 173.1 m), Khon Kean province, S. Phlaingam leg.; 1 ♂ and 1 ♀, 4/VII/2015, Kasetsart University (13°50′59″ N 100°34′26″ E, altitude 4.48 m), Bangkok province, P. Senawong leg.; 1 ♂, 25/II/2018, Ban Nong Ket (12 o 57′18′′ N, 99 o 39′12′′ E, altitude 130.2 m), Phetchaburi province, T. Saetung leg.; 1 ♂ and 1 ♀, 22/XII/ 2017, Wat Singkhon Wararam (16 o 47′130′′ N, 99 o 39′12′′ E, altitude 134.6m), Tak province, T. Saetung leg.; 2 ♂♂ and 2 ♀♀, 28/IV/2018, Ban Na district (14 o 16′41′′ N, 101 o 00′57′′ E, altitude 8.6 m), Nakhon Nayok province, T. Saetung & P. Sompan leg.
Description of the male larva. Larvae small, body very slender, (Fig. 10) coloration yellowish.
Head: Head almost pentagonal, wider than 1.5 × head length (Figs. 13–16). Labrum: distal half covered with sparse small simple setae, anterior margin flattened ventrally with sparse long simple setae. Clypeus with sparse small simple setae; frons and vertex are glabrous with three prominent ocelli. Concave occiput with tufts of simple setae on lateral occiput margin near the margin of compound eyes (Fig. 17). Postocular lobes curvilinear in outline with several scattered spiniform setae; posterolateral corner almost round. Compound eyes narrow and rounded, protruding on lateral side, with tufts of spiniform setae near the margin of compound eyes in ventral view (Fig. 18). Antennae (Fig. 19); filiform, longer than 1.15 × head length, 7 segmented, filiform, with A3 the longest; relative length of antennomeres 1.0 (0.25 mm):1.03: 1.17: 0.97: 0.73: 0.53: 0.32, A2 and A3 with long simple setae. Labium (Fig. 20); articulation of prementum and postmentum extended at level of middle coxae of foreleg; prementum with 4 pairs of premental setae, a row of 8 spiniform setae along the distal half of lateral margins, laterodistal margin with 1 strong spiniform seta and a prominent spoon-shaped ligula with 47 minute spiniform setae along the margin (Fig. 21); sub-quadrangular postmentum with several simple setae on ventral side; labial palp (Fig. 22) as long as 0.45 × prementum length, with five palpal setae on each side; apical lobe ending with two lobes; forming a truncate, denticulate lobe with 4 distinct teeth and 1 small tooth and end hook, a movable hook slender and pointed and approximately 0.51 × as long as palp length. Maxilla (Figs. 23–24); galeolacinia with 6 teeth, apical tooth the largest, three dorsal teeth of the approximately same size with 6 long serrate carpus setae, and three ventral teeth of different sizes with 3 simple setae and 8 serrate carpus setae. Mandible (Figs. 25–26); well-developed long teeth on each incisor lobe, without a molar crest; left mandible with five incisor teeth, two molar teeth (a = b); right mandible with five incisor, single molar teeth, one addition tooth, following mandibular formula: L 1+1’234 0 a b/ R 1+1’234 y a.
Thorax: Narrower than the head, middle lobe of prothorax with a shallow groove in middle; pronotum approximately hexagonal, with scattered simple setae, lateral margins almost rounded, pronotal disc smooth. Synthorax mostly glabrous, wing pads parallel, mostly pale; anterior and posterior wing pads reaching almost S4. Legs (Figs. 27–29); almost flat and long; femora thin with a dark band on the posterior side and scattered simple setae, hind femora as long as the 1.61 × length of fore and mid femora. Tibia comb with scattered tridentate setae, a few simple setae (Fig. 30). Tarsi with two row of tridentate setae, tarsal formula 3-3-3, with 2 simple claws and pulvilliform empodium.
Abdomen: Slender and cylindrical, narrowed caudally, abdominal terga with scattered simple setae, few spiniform setae and longitudinal pale band along the midline of each segment. Posterior margins with a few dark-brown spots. Abdominal sterna with a dark stripe along the midline with a distinct network of tracheoles, scattered simple setae and spiniform setae. Male gonapophyses (Figs. 32, 33); poorly developed, sharply pointed, widely divergent in ventral view. Male cerci (Figs. 31–33); prolate sub-spheroid shape, concave on inner surface and rounded tip. Caudal lamellae transparent, of denudate vertical lamella type, with an irregular rounded tip and wider in the distal half, with 5 irregular transverse bands of chocolate-brown pigment. Well-developed tracheation with a median trachea with secondary and tertiary branches. Median gill (Fig. 46a); with 6 long simple setae on dorsal margin and 6 sparse simple setae on ventral margin; lateromedial carinae with 5 spiniform setae. Lateral gills (Fig. 46b); with rows of 10 spiniform setae on anterodorsal margin and 5 sparse simple setae on ventral margin; lateromedial carinae with 6 spiniform setae.
Description of the female larva. As male, unless otherwise stated.
Female gonapophyses; with lateral valves slightly divergent, tips sharply pointed, lateral valves extending to posterior margin of S10, a row of setae along ventral margin; central valves slender, apically rounded, and slightly shorter than lateral valves (Figs. 35–36). Female cerci (Figs. 34–36); with a small cone and blunted tip.
Larval morphological variation. Both reared and molecular specimens exhibit some variation. Coloration varied, pale yellowish-cream to yellowish-brown or greenish-yellow (Figs. 11–12). Articulation of prementum and postmentum extended at level of middle coxae of foreleg up to anterior coxae of midleg. Prementum with 4 pairs of premental setae (if three, with one short seta), denticulate lobe of labial palp with 4 distinct teeth, 1–2 small teeth, and a row of 6–9 spiniform setae along the distal half of lateral margins, laterodistal margin with 1–2 strong spiniform setae and a prominent spoon-shaped ligula with 37–46 minute spiniform setae along the margin. Anterior and posterior wing pads reaching half of S3 to almost S5. Caudal lamellae with an irregular rounded tip and acute tip, half with 3–5 irregular transverse bands of chocolate-brown pigment. Median gill with 4–8 long simple setae on dorsal margin and 4–8 sparse simple setae on ventral margin; lateromedial carinae with 4–8 spiniform setae. Lateral gills with rows of 9–15 spiniform setae on anterodorsal margin and 1–8 sparse simple setae on ventral margin; lateromedial carinae with 4–8 spiniform setae. Female gonapophysis; lateral valves extending to posterior margin of S9 up to S10.
Measurements. (in mm; n =10): total length of body without caudal lamellae = 8.11–11.61; length of caudal lamellae = 3.00–6.10; width of head = 1.44–2.30; length of antenna = 1.34–1.58; width and length of prementum =1.16–1.44 and 1.28–1.60; length of labial palp = 0.54–0.80; length of movable hook = 0.24–0.40; length of inner and outer wing pads = 1.64–3.07 and 1.50–2.83; length of femora (fore: mid: hind) = 0.70–1.53: 0.96–1.78: 1.10–2.13; length of tibiae (fore: mid: hind) = 0.82–1.60: 0.92–1.83: 1.04–2.13; length of tarsi (fore: mid: hind) = 0.44–1.00: 0.44–0.76: 0.50–0.77.
Molecular analysis. The COI tree (658 bp) strongly supported the formation of a monophyletic clade by the larvae and the adult Agriocnemis minima, as well as with A. femina femina and A. pygmaea (PP = 1) (Fig. 37). Agriocnemis minima also forms a sister group with A. femina femina and A. pygmaea. The uncorrected pairwise genetic distances among the three species of Agriocnemis in Thailand are shown in Table 2. The intraspecific genetic distance ranged from 0.2% to1.9%, whereas the interspecific genetic distance ranged from 11.3% to 18.9%.
Biological notes. The larvae of Agriocnemis minima inhabit many habitats of lentic waters, such as marshy ponds with vegetation, paddy fields and pools of streams (Figs. 38–41). They are usually found together with other damselfly species (Argiocnemis rubescens Selys, 1877, Pseudagrion microcephalum (Rambur, 1842), P. australasiae Selys, 1876, P. rubriceps Selys, 1876, Ceriagrion auranticum Fraser, 1922, C. chaoi Schmidt, 1964, C. cerinobellum (Brauer, 1865), Pseudocopera cilliata (Selys, 1863), and Ischnura senegalensis (Rambur, 1842)). We found adults of all three Agriocnemis species in these habitats (Figs. 42–45).
description: Published as part of Saetung, Tosaphol & Boonsoong, Boonsatien, 2019, A review of genus Agriocnemis larva (Odonata: Coenagrionidae) from Thailand including a description of the final stadium larva of Agriocnemis minima Selys, 1877 with supporting molecular (COI) data, pp. 579-599 in Zootaxa 4711 (3) on pages 586-594, DOI: 10.11646/zootaxa.4711.3.9, http://zenodo.org/record/3586717