Mollitrichosiphum (Metatrichosiphum) tumorisiphum Qiao & Jiang

Jiang, Li-Yun, Chen, Jing & Qiao, Ge-Xia, 2015, A new species of Mollitrichosiphum Suenaga from Taiwan Island (Hemiptera, Aphididae), based on morphological characteristics and DNA sequences, ZooKeys 524, pp. 45-63 : 46-50

Taxon classification Animalia Hemiptera Aphididae

Mollitrichosiphum (Metatrichosiphum) tumorisiphum Qiao & Jiang sp. n.

Descriptions.

Apterous viviparous female: Body elongated oval (Fig. 13), yellow green in life, with pairs of emerald green dorsal markings and pale brown siphunculi (Figs 38-41).

Mounted specimens. Body pale brown, with head and prothorax fused. Dorsal setae thick, long and pointed (Figs 6, 21).

Head. Ocular tubercles dark brown, well developed. Dorsum of head with three pairs of setae between antennae, and 4-6 setae between eyes. Maximum lengths of cephalic setae 4.3-5.7 times as long as basal diameter of antennal segment III. Front flat, antennal tubercles slightly developed (Figs 1, 14). Antennae 6-segmented (Figs 2, 16-17), 0.71-0.72 times as long as body length. Processus terminalis 1.3-1.5 times as long as base of the segment. Antennal segments I–IV, basal half of segment V and of base of segment VI pale brown, other parts of segment V and VI brown. Antennal segments III–VI with short imbrications. Antennal setae pointed. Antennal segment I with only short setae; segments II–V with long and short setae, setae on the inner side of the segment distinctly longer, thicker and more numerous than setae on the outer side of the segment; segments I–VI each with 4-6, 4 or 5, 16-23, 3 or 4, 3 or 4, (3 or 4)+(4-6) setae, respectively; apex of processus terminalis with 3 or 4 short blunt setae; maximum length of setae on segment III 4.5-5.7 times as long as basal diameter of the segment. Rostrum reaching hind coxae, sometimes abdominal segment I; ultimate rostral segment pale brown, except for brown apex, long and wedge-shaped (Figs 3, 18), 4-6 times as long as its basal width, 1.4-1.8 times as long as second hind tarsal segment; segment IV and V obviously separated; with 3 pairs of primary and 3 pairs of secondary setae.

Thorax. Mesosternal furca with a short stem (Figs 4, 19). Pronotum with 1 pair of anterior spinal, 3 or 4 posterior spinal, 1 pair of anterior marginal and 2 pairs of posterior marginal setae Legs slender. Femora and tibiae pale brown. Hind femur 0.9-1 times as long as antennal segment III. Hind tibia 0.75-0.83 times as long as body, with 57 -62 transverse ridges on basal 3/4 of the segment (Figs 5, 20). Setae on legs short, pointed or acuminate. Maximum length of setae on hind tibia 1.8-2.2 times as long as mid-width of the segment. Tarsi brown, with transverse imbrications. Chaetotaxy of first tarsomeres: 7, 7, 7.

Abdomen. Abdominal tergite I with 4-6 spinal and pleural setae, and 2 pairs of marginal setae, tergite VIII with one pair of spinal setae. Maximum lengths of marginal setae on abdominal tergite I and dorsal setae on tergite VIII 3.3-4.0 and 2.3-3.4 times as long as basal diameter of antennal segment III, respectively. Venter of abdominal segments II–VI with coarse spinules on pleural and sub-marginal area (Figs 7, 22). Spiracles oval and open, on pale brown spiracular plates. Siphunculi brown, long and tubular, strongly swollen over most of length and constricted near apex (Figs 8, 23), flange distinct; 0.3-0.4 times as long as body, 1.3-1.5 times as long as antennal segment III, 8.7-12.6 times as long as its basal width, 4.2-5.6 times as long as width of expanded part, 10.7-13 times as long as its distal width. Siphunculi with spinules evenly distributed and with spinulose imbrications at apex. Each siphunculus with 95-118 setae, long and pointed. Cauda, anal plate and genital plate pale brown. Cauda broadly rounded (Figs 9, 24), with spinules and round apex; 0.2-0.4 times as long as its basal width; with 8-10 setae. Anal plate transversely elliptical (Figs 10, 25), with spinules and with a transverse band of cell-like markings on spinal area, with 16 or 17 setae. Genital plate transverse oval (Figs 11, 26), with spinules, 4-6 anterior and 4-8 posterior setae. Gonapophyses three, spinal one with 6 setae and each pleural one with 3 setae.

Alate viviparous female: Body elongate oval (Fig. 27), yellow green in life, with green dorsal markings (Figs 39, 41), dark brown forewing veins and dark brown siphunculi (Fig. 41).

Mounted specimens. Dorsal setae thick, long and pointed.

Head. Head, antennae and ultimate rostral segment dark brown. Dorsum of head with 6 setae between antennae, and 4-6 setae between eyes. Maximum lengths of cephalic setae 4.6-4.9 times as long as basal diameter of antennal segment III. Front flat (Fig. 28). Antennae 6-segmented (Figs 12, 29-30), 0.9 times as long as body length. Processus terminalis 1.4 times as long as base of the segment. Antennal segments III–VI with short imbrications. Antennal setae thick, long and pointed; segments I–VI each with 4, 4 or 5, 18, 4 or 5, 4, 4+5 setae, respectively; apex of processus terminalis with 4 short blunt setae; length of setae on segment III 5.1-5.4 times as long as basal diameter of the segment. Antennal segment III with 7-9 nearly round secondary rhinaria, distributed on basal 2/3 of the segment. Rostrum reaching abdominal segment I; ultimate rostral segment long wedge-shaped (Fig. 31), 5.5 times as long as its basal width, 1.7 times as long as second hind tarsal segment; segment IV and V obviously separated; with 3 pairs of primary and 2-3 pairs of secondary setae.

Thorax. Thorax, femora, tibiae and tasi dark brown. Pronotum with 6 spinal and pleural setae and 3 pairs of marginal setae. Legs slender. Inside of distal half of femora with short spare spinulose imbrications. Hind femur 0.9-1 times as long as antennal segment III. Hind tibia 2 times as long as body, with 69-72 transverse ridges on basal 3/4 of the segment (Fig. 33). Setae on legs short and pointed. Maximum length of setae on hind tibia 2.5-2.9 times as long as mid-width of the segment. Second tarsal segments with transverse imbrications. Chaetotaxy of first tarsomeres: 7, 7, 7. Fore wings with media twice branched and distal 1/3 of CuR1 Rcurved to media; hind wings with 2 oblique veins.

Abdomen. Abdominal tergites I–VI with spinal, pleural and marginal sclerotic markings fused into a large brown patch; tergites VII and VIII each with one brown transverse patch. Abdominal tergite I with 8-10 setae, tergite VII with 4 setae, tergite VIII with 2 setae. Maximum lengths of marginal setae on abdominal tergite I and dorsal setae on tergite VIII 1.7-2.0 and 3.4-4.0 times as long as basal diameter of antennal segment III, respectively. Venter of abdominal segments III–VI with coarse spinules on pleural and sub-marginal area. Spiracles oval and open, on brown oval spiracular plates. Siphunculi long. tubular, distinctly swollen on distal half (Fig. 34), flange distinct, basal 2/3 of siphunculi dark brown and distal 1/3 brown, with spinules evenly distributed and with spinulose imbrications at apex; 0.5-0.6 times as long as body, 1.8-2 times as long as antennal segment III, 13.9-19.5 times as long as its basal width, 10.4-13 times as long as width of expanded part, 21.3-25 times as long as its distal width; each with 105-120 long and pointed setae. Cauda, anal plate and genital plate brown. Cauda broadly rounded (Fig. 35); 0.26-0.28 times as long as its basal width; with spare spinulose imbrications and 12 setae. Anal plate transversely elliptical, with spare spinulose imbrications and 52-58 setae (Fig. 35). Genital plate transverse oval (Fig. 36), with spinules and 84-104 setae. Gonapophyses three, spinal one with 8 setae and each pleural one with 4 setae.

Specimens examined.

Holotype: apterous viviparous female, CHINA, Taiwan Island: Tamanshan Mountain, Fuxing Town, Taoyuan County, 24.70°N, 121.43°E, altitude 1630m, 14 June 2011, No. 26510 –1–1– 1, on Fagus longipetiolata , coll. X.L. Huang. Paratypes: 3 apterous viviparous females, 1 alate viviparous females and 1 second instar larva, 1 apterous viviparous female and 1 alate viviparous female (BMNH), with the same collection data as holotype; 1 apterous viviparous female, Bilu, Xiulin Town, Hualian County, 24.00°N, 121.21°E, altitude 2150m, 20 July 2011, No. 26515, on Fagus longipetiolata , coll. X.L. Huang.

Etymology.

The name of this species is derived from its most distinctive feature, its markedly swollen siphunculi. The specific name is composed of "tumor (Latin, =inflated, swelling)" and "siphum (Latin, =tube)".

Diagnosis.

The new species is distinctly different from the other known species in the genus, based on siphunculi of alatae distinctly expanded on the apical half. It is similar to the species Mollitrichosiphum (Metatrichosiphum) niitakaensis (Takahashi), but differs from the latter as follows: body with long and stout dorsal setae, pointed at apex (the latter: at least with some bifurcate dorsal setae); each siphunculus with more than 95 setae (the latter: less than 80); hind tibia with 20-63 short transverse ridges (the latter: with more than 84).

It is also similar to the species Mollitrichosiphum (Metatrichosiphum) yamabiwae Suenaga, but differs from the latter as follows in apterous viviparae: dorsal of abdomen pale brown, without sclerotic pattern (the latter: with fused dark brown sclerotic patterns); hind tibia with 57-62 transverse ridges (the latter: with 31-33); ultimate rostral segment 0.18-0.22 mm long, 4-6 times as long as basal width, 1.4-1.8 times as long as hind second tarsal segment (the latter: 0.28-0.41 mm, 6.1-8.4 times, 2.4-2.8 times); ultimate rostral segment with 3 pairs of secondary setae (the latter: with 7 pairs).

Biology.

Colonizing the underside of young leaves of new growth of Fagus longipetiolata . (Figs 38-41).