Lankaphthona binotata (Baly, 1876) Baly, 1876

Ruan, Yongying, Konstantinov, Alexander S., Prathapan, Kaniyarikkal D., Zhang, Mengna & Yang, Xingke, 2019, A review of the genus Lankaphthona Medvedev, 2001, with comments on the modified phallobase and the unique abdominal appendage of L. binotata (Baly) (Coleoptera, Chrysomelidae, Galerucinae, Alticini), ZooKeys 857, pp. 29-58 : 29

1. Lankaphthona binotata (Baly, 1876) comb. nov. Figs 1, 2, 3, 8G

Thyamis binotata Baly, 1876: 583. Type locality: China, Shanghai. Type depository: BMNH. Lectotype designated by Konstantinov and Lingafelter (2002: 214).

Aphthona binotata : Chen 1934: 368.

Zipangia binotata : Konstantinov and Lingafelter 2002: 214.

Trachyaphthona (Longitarsella) binotata : Medvedev 2009: 202.

Distribution.

China: Shanghai ( Baly 1876), Jiangsu ( Ruan and Yang 2015), Fujian (new record).

Description.

Body entirely yellow to yellow brown, each elytron with a black round spot (with indistinct margin) slightly behind middle. Body oval, slightly elongated in dorsal view, dorsum convex in lateral view. Body length: 1.90-2.20 mm. Body width: 1.10-1.20 mm. Body length to width ratio: 1.80-1.85. Pronotum width to length ratio: 1.75-1.80. Pronotum width at base to width at apex ratio: 1.00-1.05. Elytron length (measured along suture) to width of both ratio: 1.25-1.30. Length of elytron to length of pronotum ratio: 3.30-3.40. Width of elytra at base (measured in middle of humeral calli) to width of pronotum at base ratio: 1.10-1.15.

Vertex without punctures, except 2-3 on each side near supraorbital sulcus. Frontal ridge moderately developed, not wide, slightly convex. Sides of frontal ridge without sulci or large punctures, slightly sloping. Antennal calli obliquely elongated, sub-triangular, closely conjoined; lower part narrowed, slightly entering interantennal space. Top of frontal ridge acute, slightly produced between antennal calli. Frontal ridge in lateral view moderately convex. Width of frontal ridge to antennal sockets (counting surrounding ridges) ratio 1.05-1.15. Eyes moderately large, distance between eyes (just above antennal sockets) to transverse diameter of one eye in frontal view ratio: 2.45-2.55. Longitudinal diameter of eye to transverse diameter of eye in frontal view ratio: 2.10-2.15. Distance between antennal sockets to transverse diameter of one antennal socket ratio: 1.05-1.15. Supraorbital and orbital sulci moderately developed. Supraantennal, supracallinal sulci shallow. Frontolateral sulcus obsolete. Orbit wide, as wide as diameter of one antennal socket.

Antennae filiform, moderately long, about 0.8 times body length. Proportions of antennomeres as follows: 12:6:7:8:9:9:10:12:11:10:13. Antennomere 1 almost as long as next two combined. Antennomere 2 robust, slightly shorter than 3 and 4. Length to width of antennomere 9 ratio: 2.30-2.40. Length to width of antennomere 10 ratio: 2.00-2.05. Length to width of antennomere 11 ratio: 2.55-2.60.

Pronotum almost rectangular. Pronotal disc slightly convex. Base of pronotum with a shallow antebasal impression. Pronotal punctures sparse, shallow and minute. Diameter of pronotal punctures 3-4 times smaller than distance between adjacent punctures. Pronotal punctures nearly as large as elytral ones. Anterolateral callosity of pronotum well developed, truncate and elongate, facing anterolaterally. Pronotum parallel sided, not converging forward; lateral margin obviously explanate, slightly sinuate.

Elytron without impressions or ridges. Elytral humeral callus moderately developed. Elytral punctures minute, confused.

Length (not counting trochanter) to maximum width of metafemur ratio: 1.90-1.95. Length to width of metatibia in lateral view ratio: 5.80-5.90. Width of metatibia at base to width at apex in dorsal view ratio: 0.45-0.50. Length of metatibia to length of first metatarsomere ratio: 2.0-2.2. Length of metafemur to metatibia ratio: 1.05-1.10. Length of first metatarsomere to that of second metatarsomere ratio: 2.10-2.20.

Intercoxal ridges on first abdominal ventrite obsolete in both male and female; males with a spoon-shaped appendage arising near hind margin of first abdominal ventrite, produced anteriorly (Fig. 3). Numerous elongate setae present on lateral margin of appendage.

Aedeagus of male robust, oval in cross section. In lateral view, aedeagus robust and sinuate, with apex slightly bent dorsally. Aedeagus, in ventral view, gradually narrowed near apex, apical denticle absent. Ventral groove on aedeagus poorly developed. Phallobase (i.e., tegmen, spiculum) of male genitalia sheath-shaped, encircling middle of aedeagus. Phallobase with a longitudinal sclerotized rod-shaped apodeme in middle, produced anteriorly beyond anterior margin of sheath-like part (Fig. 1 I–J: anterior apodeme) and a transverse sclerotization on posterior margin, both together forming a ‘Y’ shaped sclerotization.

Receptacle of spermatheca cylindrical. Spermathecal pump shorter and smaller than receptacle. Basal part of spermathecal duct (between spermathecal gland and receptacle) wide and coiled, longer than receptacle. Apex of spermathecal pump wide, rounded. Lateral margins of vaginal palpus more or less parallel to each other. Vaginal palpus widened near base, weakly sclerotized from base to middle, moderately sclerotized distally. Tignum spear-shaped.

Variability.

Depth of pronotal antebasal transverse impression and length of first metatarsomere vary slightly between individuals.

Only a single type of elytal maculation - a round spot with indistinct margin near middle of each elytron - was observed in our study.

Type material.

♀ (BMNH), labels: 1) Type H.T.; 2) Baly coll.; 3) Aphthona binotata Baly ♀; 4) A. Warchalowski det. 1965; 5) Thyamis binotata Baly, Shanghai.

Material.

4♂4♀ (IZCAS, preserved in ethanol), CHINA, Fujian, Pingtan Island, 5.VI.2014, alt. 200 m, leg. Yongying Ruan; 2♂3♀ (USNM, dry specimens), China, Fujian, Pingtan Isl., WP-449, 25°33.252'N, 119°52.253'E, 5.vi.2014, h = 202 m.

Remarks.

Lankaphthona binotata resembles L. yunnantarsella Ruan, Konstantinov & Prathapan, sp. nov. due to the similarity in elytral maculation. However, L. binotata can be separated from the latter by the much shorter antennae, eyes not prominently enlarged and males with abdominal appendage on first abdominal ventrite.

This species was originally published by Baly (1876) in Thyamis . Subsequently, it was placed in Aphthona by Chen (1934). Konstantinov and Lingafelter (2002) transferred it to Zipangia after they studied the type material. Medvedev (2009) misidentified it and used misidentified specimens as the type for the newly erected subgenus Longitarsella (in genus Trachytaphthona ). Despite the studies of authors mentioned above, the sheath-shaped phallobase and the highly specialized abdominal appendage on the first abdominal ventrite of males remained unknown prior to this study. We have dissected five males and it turns out that both structures are rather stable in shape.