Psylla sarcospermae (Li)

Luo, Xinyu, Li, Qiang, Li, Fasheng & Cai, Wanzhi, 2013, A revision of the endemic Chinese genus Cornopsylla (Hemiptera: Psyllidae), with potential pests on Zanthoxylum (Rutaceae), Zootaxa 3646 (2), pp. 127-148 : 144-147

Psylla sarcospermae (Li) comb. nov.

Cornopsylla sarcospermae Li, 2011: 560 .

Described from Sarcosperma kachinensis (Sapotaceae) , from Yunnan Province, based on 4 males and 1 female, this species does not fit the diagnosis of Cornopsylla given above, and is definitely not a member of that genus. As no suitable genus had been found for it, and as Psylla sensu Li (2011) already contains many not-so-typical species from southern China, making it a paraphyletic or maybe even polyphyletic group, C. sarcospermae is here temporarily assigned to Psylla .

Diagnosis: Body small to medium sized, glabrous. Surface of vertex and dorsal aspect of thorax finely sculptured with continuous scaly microstructures. Genal processes conical, divergent from the base, harshly narrowed at basal 1/3, then slightly curved outwards apically, widely separated; apex subacute. Antenna 10- segmented, no longer than twice of head width, with one rhinarium on segments IV, VI, VIII and IX subapically. Propleuron suture reaching posterior angle of pronotum, without sign of forking; proepimeron wider and much shorter than proepisternum. Fossa of trochantinal apodeme present in central portion of mesokatepisternum. Metacoxa with well developed cone-shaped meracanthus; thin outer wall with one single seta, and a small field of micro spinules near meracanthus. Metatibia without distinct basal spine, and with 6 (in one case 7) stout apical spurs not conspicuously grouped. Metabasitarsus with two black spurs. Fore wing membranous, hyaline and clear, with shape and venation similar to many Cacopsylla spp.; pterostigma relatively broad, ending at apical 1/3 of cell r1; surface spinules present in all cells, leaving wide spinule-free bands along veins; radular spinules present in cells cu1, m2, m1 and r2, in r2 relatively dim. Ventral surface of abdomen with long setae (not as long and dense as Cornopsylla ). Male proctiger unipartite, without conspicuous posterior lobe. Paramere long and slender, curved twice; apex subacute and moderately curved inward; inner surface with one large quadrate extended lobe, with a dense cluster of stout setae covering most area of it. Aedeagus two-segmented, simple. Female proctiger resembles some species of Cacopsylla (with a long, thin and near straight apical process) in shape, but with setation denser, shorter, more evenly spaced and of more even length. Female subgenital plate triangular, smoothly tapering apically.

The apical spurs of the metatibia are not conspicuously grouped in C. sarcospermae , and unlike that of typical Diaphorinini in texture. The superficial structure of the head and dorsal aspect of the thorax is the typical scale-andmicroscopic setae type of Psyllinae, and without the dense moderately long setae commonly seen in various body parts of most Diaphorinini species. Moreover, the male proctiger does not have posterior lobes. Taking other characters into account, C. sarcospermae is more of a Psyllinae species than a Diaphorinini species, but further studies will be needed to establish a suitable generic position.

Discussion

For adult characters, Cornopsylla possesses an irregularly grouped type of metatibial apical spurs instead of the evenly spaced type of Diaphorinini; it is also without a conspicuous posterior lobe of male proctiger. The extraordinary long setae in many body parts of Cornopsylla are conspicuously longer and sparser than typical Diaphorinini, and rather sparse in ventral aspect of thoracic pleurites; while the typical setation of Diaphorinini is relatively shorter and denser, and especially dense in ventral aspect of thoracic pleurites. For these reasons, we think the setation of Cornopsylla is not homogenous with that of typical Diaphorinini. As for the nymphal characters, including the lack of specialized setae (rod setae, lanceolate setae, sectasetae, etc.), the “conservative” form of circum anal pore field consisting of inner- and outer circumanal pore rings and without extra pore fields, wide fan-shaped tarsal arolium with well developed unguitractor and a moderately long petiole, the arrangement of sclerites all over the body, the long and strong setae in abdominal margin, all resemble many species of Psyllinae. Typical Diaphorinini fifth instar nymphs are with closely packed or relatively scattered lanceolate setae/sectasetae in margin of wing pads and/or abdominal margin, except Epipsylla , which is without specialized setae. Epipsylla is a genus of putative close relationship with Cornopsylla . However, there are more profound differences than superficial resemblance between them. Epipsylla is without genal whip setae, and with typical Diaphorinini body setation and apical spurs, which make it intrinsically different with Cornopsylla . As for the host plants, species on Rutaceae are scattered in most families of Psylloidea, giving no particular indication of close relationship. And for all the reasons mentioned above, we incline to the argument that Cornopsylla is a member of Psyllinae, and expect further studies invoking integrated methods to verify or overthrow it.

In Yin Shanshan’s investigation, she gave the information that Cornopsylla magna has always been a dominant species as a pest in Zanthoxylum plantation in Yongshan County, Zhaotong, Yunnan, over the past decades. Nevertheless, no psyllid species has ever been officially recorded as even subordinate pests on cultivated Zanthoxylum bungeanum . In China, researches about pest control of Z. bungeanum are mostly conducted by local scholars of Gansu, Shaanxi and Ningxia, based on local plantations. However, Cornopsylla does not occur in these areas. Guidelines given about the pest control of Z. bungeanum by these authors are unilaterally aiming at pests such as Podagricomela spp. ( Coleoptera : Chrysomelidae ), Papilio xuthus ( Lepidoptera : Papilionidae ), Aphis gossypii ( Hemiptera : Aphididae ), etc. (Wei et. al. 2012; Zhu et al. 2004); some are even rather sweeping without an emphasis. Measures on pest control may probably neglect Cornopsylla spp., providing them a readily pass into dominance. As far as we know, distribution of Cornopsylla spp. is restricted within subtropical mountain areas of southwestern China, which totally belong to the Oriental Region, with latitude ranging within 24°–29°. They will possibly be discovered or rise as major pests in other localities in this area, but not probably outside it.

Besides Cornopsylla spp., there are other psyllid species, in three different families, in the world recorded from Zanthoxylum around the world, as follows [partly cited from Ouvrard (2013)]:

CALOPHYIDAE

Calophya sp. (Burckhardt & de Queiroz 2012), from Brazil, on Zanthoxylum sp.

PSYLLIDAE

Cacopsylla fagarae (Fang & Yang 1986) , from Taiwan, China, on Z. scandens (= Z. cuspidatum ).

Cacopsylla evodiae (Miyatake 1965) , from China ( Taiwan) and Japan, on Tetradium glabrifolium [= Euodia meliifolia = Euodia glauca ], Murraya paniculata , Zanthoxylum beecheyanum var. alatum (name unconfirmed) and Toddalia asiatica [all recorded by Inoue (2010)].

TRIOZIDAE

Hemischizocranium aloha (Caldwell 1940) , from Hawaii, on Zanthoxylum sp.

Hemischizocranium bessi Tuthill, 1956 , from Hawaii, on Zanthoxylum dipetalum .

Leuronota fagarae Burckhardt, 1988 , from Paraguay and USA, on Zanthoxylum fagara [Halbert & Manjunoth 2004, also denying the original record on Z. caribaeum (= rugosum)].

Megatrioza zanthoxyli Uchida & Beardsley, 1992 , from Hawaii, on Zanthoxylum kauaense and " Z. hawaiiensis " (name unconfirmed, it probably refers to Z. hawaiiense ).

Trioza erytreae (del Guercio 1918) from Africa and West Asia, on Clausena anisata , Zanthoxylum capense and Vepris undulata .