Miridiba lamellata, Gao and Fang, 2019

Gao, Chuan-Bu, Idrees, Atif & Li, Jun, 2022, The Miridiba lamellata Species Group (Coleoptera: Scarabaeidae) with a New Species from Yunnan, China, The Coleopterists Bulletin 76 (1), pp. 101-109 : 102-107

Miridiba lamellata Species Group

Male Genitalia. The parameres ( Gao et al. 2019: figs. 15–18) consist of two dorsal and two ventral branches separated in dorsal and lateral views. All the branches are lamella shaped. Dorsal branches are more prolonged and broader than ventral branches. The collum is flat. The endophallus consists of temones on the dorsum, an epithelium at the proximal part, and a wrinkled sac at the terminal endophallus. The temones consist of two slender and separated apophyses.

Female Genitalia. Female genitalia are of the tubular type (Lindroth and Palmén 1970) and are similar to other Rhizotrogini species (Coca-Abia and Martín-Piera 1991). They consist of an accessory gland, a bursa copulatrix, a membranous genital chamber, a membranous median oviduct, and a spermatheca. The genital chamber bears two pairs of vestigial tergites on the anal fold, a pair of sensory plates on the gonopore fold, and two vestigial sternites on the ventral side.

MIRIDIBA DugongA Gao , new species zoobank.org/ urn:lsid:zoobank.org:act:D131C2D6-6A78-43C0-A4CF-DEEA91EC66B6 ( Figs. 1–27 , 32 )

Description. Holotype, male. Body ( Figs. 1–2 ) fusiform in dorsal and lateral view; length = 17.4 mm, width across humeri = 7.4 mm. Dorsal surface glabrous. Color: Reddish brown to dark reddish brown. Head: Antenna with 10 antennomeres; antennal club with 3 antennomeres, equal in length to antennomeres 2–7 combined, and 1.5× longer than antennomeres 3–7 combined ( Fig. 3 ). Clypeus with lateral margins oblique and anterior margin moderately emarginate. Clypeus wider and shorter than frons; dorsal surfaces of clypeus and frons densely punctate ( Fig. 4 ). Frontoclypeal suture clearly defined and sinuate. Frontal carina raised moderately, and weakly arcuate ( Fig. 4 ). Interocular distance 4.0× wider than eye width (measured at medial area of eyes); eye canthus pubescent, 0.4× shorter than transverse eye width ( Fig. 4 ). Gena with long, dense, soft setae laterally ( Fig. 5 ). Mouthparts: Labrum strongly depressed medially and bearing dense microsetae laterally on dorsal side of depression ( Fig. 6 ). Maxilla consisting of cardo, galea, lacinia, maxillary palpi, and stipes; stipes punctate and moderately setiferous; galea with 6 sharp teeth; lacinia setiferous; maxillary palpi with 4 palpomeres, fourth palpomere 1.3× longer than second and third palpomeres combined ( Figs. 7A–B ). Ventral surface of mentum depressed medially; mentum with a triangular notch on anterior margin medially, each lateral side bearing 4 or 5 setae ( Fig. 8 ). Mandible setiferous on outer surface ( Fig. 9A ); dorsal surface glabrous, exposed apex smooth ( Fig. 9B ); molar lobe with a long trapezoid-shaped depression on distal portion (molar lobe of left mandible with a hole), proximal molar lobe moderately wrinkled ( Figs. 9C–D ); incisor lobe with 2 sharp teeth on left mandible ( Fig. 9E ). Thorax: Pronotal surface densely punctate, distance between punctures smaller than one puncture diameter; pronotum widest at posterior 2/5; anterior margin smooth and weakly flanged; posterior 2/5 of lateral margin smooth; anterior 3/5 of lateral margin crenulate and setiferous, serrations long and obtuse; posterior margin punctate ( Fig. 10 ). Prosternal process trapezoid and moderately concave in the middle ( Fig. 11 ). Ventral surface of thorax covered with soft setae. Metanepisternum narrow trapezoid shaped. Scutellar shield triangular, dorsal surface glabrous and densely punctate, 1.4× wider than long ( Fig. 12 ). Elytra: Discal costae absent; sutural costae weak ( Fig. 1 ); epipleura covered with a few short setae before apex ( Fig. 13 ). Legs: Profemur densely punctate and setiferous, setae soft and long; protibia tridentate, 2 apical teeth developed, basal tooth small; dorsal and ventral surfaces of protibia each with a sharp longitudinal carina; apical spur reaching basal 1/3 of protarsomere 1 ( Figs. 14A–B ). Dorsal surface of meso- and metafemora moderately punctate; each with soft, thin setae near anterior margin and long, robust setae near posterior margin; metafemur 3.0× longer than wide; metafemur 2.4× longer than wide ( Fig. 15 ). Outer surface of meso- and metatibiae with a complete transverse carina; dorsolateral margin of meso- and metatibiae with 1 or 2 pubescent spines in basal 1/4; dorsointernal margins of meso- and metatibia with 4 spines ( Figs. 16–17 ). Two apical spurs of metatibia lanceolate and straight; spurs differing in size, upper spur 1.2× longer than lower spur ( Fig. 18 ). Apices of pro- and mesotarsomeres 1–4 ventrally each with a tuft of dense microsetae ( Fig. 19 ); metatarsomere 1 as long as metatarsomere 2. Pro-, meso-, and metatarsal claws each with a strong median tooth ( Fig. 20 ). Abdomen: Abdominal ventrite 1 and ventrite 2–6 posteriorly densely punctate and setiferous, setae short; ventrite 5 weakly depressed on posterior half; anterior margin of ventrite 6 developed ( Fig. 21A ). Pygidium: 1.4× wider than long; fan-shaped; center area slightly raised; punctate and moderately setiferous; distance between punctures greater than one puncture diameter; setae on dorsal surface short to long from base to apex; two lateral margins at a right angle ( Figs. 21A–B ). Male genitalia: Male genitalia consisting of genital segment and tegmen; tegmen consists of phallobase and parameres ( Figs. 22 ). Phallobase 1.3× longer than parameres; basal fourth reduced ( Fig. 22 ). Parameres punctate on dorsal and lateral side; collum flat; a wide, longitudinal depressed suture in the middle of collum; two bilateral symmetrical fluid grooves before collum ( Fig. 23A ). Parameres with a pair of dorsal branches and a pair of ventral branches; all the branches lamella shaped. Dorsal branches significantly larger than ventral branches. Dorsal branches extending anteriorly, weakly concave inwards and moderately rounded at apex ( Figs. 23B–C ). Endophallus consisting of temones on dorsum, an epithelium at proximal endophallus, and a wrinkled sac; temones with 2 apophyses slender and separated; epithelium covered with soft sensillae; a raspulae covered with dense cone-shaped sensillae present ventrally on proximal epithelium ( Fig. 24 ). Spiculum gastrale Y-shaped with two branches (angle 135°), united by membranous region ( Fig. 25 ).

Allotype, Female. Length = 15.3 mm, width across humeri = 7.2 mm. Allotype differing from holotype in the following respects: antennal club 1.2× longer than antennomeres 3–7 combined, 0.8× shorter than antennomeres 2–7 combined. Clypeus moderately wider and shorter than frons. Interocular distance 5.2× wider than eye width. Maxillary palpi with 4 palpomeres, fourth palpomere 1.5× longer than palpomeres 2–3 combined. Scutellar shield 1.3× wider than long. Metafemur 2.4× longer than wide. Two apical spurs of metatibia moderately curved. Pygidium 1.4× wider than long. Female genitalia ( Figs. 26–27 ): Genital chamber membranous, dorsal wall with anal and gonopore fold; anal fold at posterior genital chamber with 2 pairs of vestigial tergites bilaterally symmetrical, located on lateral sides of rectum; ventral wall of gonopore fold with 1 pair of sensory plates bearing genital styli; anterior genital chamber with a pair of vestigial sternites ventrally. Two accessory glands located on both sides of anterior end of genital chamber. Median oviduct membranous. Spermatheca of a short rodlike shape; spermathecal gland longer than spermatheca. Bursa copulatrix with a large pouch at proximal part bearing a peduncle connected to median oviduct.

Variability of Paratype. The paratype slightly differs in size: body length 16.2 mm, width across humeri 6.9 mm.

Diagnosis. Miridiba dugonga can be separated from the other Miridiba species by the following combination of characteristics: dorsal surfaces densely punctate; antenna composed of 10 antennomeres; anterior margin of clypeus moderately emarginate; each ventral surface lateral to the notch of the mentum bearing 4 or 5 setae; lateral margin of pronotum crenulate, serrations long and obtuse; scutellar shield densely punctate; elytra glabrous; epipleura covered with few short setae before apex; a sharp carina present on dorsal surface of protibia; a complete carina present on outer surface of meso- and metatibiae; 4 spines on dorsointernal margin of metatibia; metatarsomere 1 equal in length to metatarsomere 2; ventrites 2–6 densely punctate and setiferous; pygidium punctate, setiferous; lamellar branches of the parameres present; dorsal branches of paramere extend anteriorly.

Type Locality. CHINA: Yunnan Province: Xishuangbanna Dai Autonomous Prefecture: Jinghong City (22.15810°N, 100.66543°E; 729 m) .

Type Material. Three types: 1 holotype, 1 female allotype, and 1 male paratype. Holotype male, labeled “ Yunnan, Jinghong, Naban River Watershed Natural Reserve / Naban tea processing factory (forest)/ 2009.V.26 729 m / Institute of Zoology , Chinese Academy of Sciences [typeset, in Chinese ] // 22.15810°N / 100.66543°E, Malaise trap / Leg. Ling-Zeng Meng / Institute of Zoology , Chinese Academy of Sciences [typeset, in Chinese] // Naban II / 3 B1 / 26.05.2009 / leg. IZ.M / Present by Naban River Watershed Natural Reserve [Typeset, in Chinese] / / Holotype ♂ Ruji June beetle [in Chinese] / Miridiba dugonga sp. nov. / Gao, 2021 [red label, typeset]”, deposited in IZCAS. Allotype female, labeled “ Yunnan, Jinghong, Naban River Watershed Natural Reserve / Naban tea processing factory (forest) / 2009.V.26 729 m / Institute of Zoology , Chinese Academy of Sciences [typeset, in Chinese]// 22.15810°N / 100.66543°E, Malaise trap /Leg. Ling-Zeng Meng/ Institute of Zoology , Chinese Academy of Sciences [typeset, in Chinese]// Allotype ♀ Ruji June beetle [in Chinese]/ Miridiba dugonga sp. nov. /Gao, 2021 [blue label, typeset]”, deposited in IZCAS. Paratype male, labeled “ Yunnan, Jinghong, Naban River Watershed Natural Reserve /Naban tea processing factory (forest) / 2009.V.26 729 m / Institute of Zoology , Chinese Academy of Sciences [typeset, in Chinese]// 22.15810°N / 100.66543°E, Malaise trap /Leg. Ling-Zeng Meng/ Institute of Zoology , Chinese Academy of Sciences [typeset, in Chinese]//Naban II/3 B1/ 26.05.2009 /leg. IZ.M/Present by Naban River Watershed Natural Reserve [Typeset, in Chinese]// Paratype ♂ Ruji June beetle [in Chinese]/ Miridiba dugonga sp. nov. /Gao, 2021 [yellow label, typeset]”, deposited in IZCAS .

Chinese Name. 儒脊鳃金龟

Remarks. We classified M. dugonga in the M. lamellata species group based on the lamellar branches of the parameres. By the following four characteristics, it can be distinguished from M. lamellata : (1) the serrations on the lateral margin of M. dugonga ( Fig. 10 ) are longer and more obtuse than those on M. lamellata ( Fig. 28 ); (2) the lateral ends of the anterior margin of the pronotum are smooth on M. dugonga ( Fig. 10 ), but crenulate in M. lamellata ( Fig. 28 ); (3) the dorsal branches of the parameres of M. dugonga are straight ( Figs. 23A, C ), but curved in M. lamellata ( Gao et al. 2019: fig. 16); (4) the length/width ratios of the dorsal and ventral branches of the parameres of M. dugonga ( Fig. 23b ) are significantly larger than in M. lamellata ( Gao et al. 2019: fig. 15).

Etymology. We name this species dugonga , from the feminine form of the marine animal Dugong dugon (Müller, 1776) ( Mammalia: Sirenia : Dugongidae ).The branches of parameres have a peculiar morphology that resembles the head of a dugong.This name should be treated as a noun in apposition.

Figures

Figs. 1–2. Miridiba dugonga, new species, habitus. 1) Dorsal view; 2) Lateral view. Scale bars = 5 mm.

Figs. 3–13. Miridiba dugonga, new species. 3) Antenna; 4) Head, dorsal view; 5) Gena, ventral view; 6) Labrum, dorsal view; 7) Maxilla, A) Left, B) Right; 8) Mentum, ventral view; 9) Mandibles, A) Left, lateral view, B) Left, top view, C) Left, inner view, D) Right, inner view, E) Left, ventral view; 10) Pronotum, dorsal view; 11) Prosternal process, ventral view; 12) Scutellar shield, dorsal view; 13) Epipleuron. Abbreviations: c, cardo; d, depression; es, epipleural setae; g, galea; h, hole; il, incisor lobe; l, lacinia; ml, molar lobe; n, notch; p, palpi; s, stipe; st, serrate. Scale bars = 1 mm.

Figs. 14–27. Miridiba dugonga, new species. 14) Left protibia, A) Dorsal view, B) Ventral view; 15) Left metafemur, ventral view; 16) Left mesotibia, lateral view; 17) Left metatibia, lateral view; 18) Right metatibial spurs; 19) Left protarsus, lateral view; 20) Right metatarsal claw; 21) Pygidium, A) Lateral view, B) Dorsal view; 22) Tegmen, lateral view; 23) Parameres, A) Dorsal view, B) Lateral view, C) Ventral view; 24) Endophallus, lateral view; 25) Spiculum gastrale, dorsal view; 26) Female genitalia; 27) Genital chamber.Abbreviations: ag, accessory gland; bc, bursa copulatrix; db, dorsal branches; di, dorsaointernal margin; dl, dorsolateral margin; ep, epithelium; g, groove; gc, genital chamber; mo, median oviduct; p, peduncle; pb, phallobase; pm, parameres; r, raspulae; s, spermatheca; t, temones; vb, ventral branches; vt, vestigial tergites. Scale bars = 1 mm for 14–19, 21–27; 0.5 mm for 20.

Fig. 32. Distribution of the species belonging to the Miridiba lamellata species group.

Figs. 28–31. Pronotum, elytra, and leg of four Miridiba species. 28) Pronotum of M. lamellata; 29) Elytra of Miridiba ciliatipennis (Moser, 1913); 30) Pronotum of Miridiba rugaticollis (Moser, 1913); 31) Metatibia of Miridiba dohrni (Brenske, 1894) (M. leucophthalma species group). Abbreviations: ts, tiny spine. Scale bars = 1 mm.