A new species of Ptilomymar (Hymenoptera, Mymaridae) and a key to the described species

Abstract Ptilomymar dianensis sp. n. (Hymenoptera, Mymaridae) from southwest China is described and illustrated. A key to the six described species is given. The type specimens are deposited in the insect collections of Northeast Forestry University, China.


Introduction
Ptilomymar was established by Annecke and Doutt (1961). Currently, this genus contains five described species, Ptilomymar rete Annecke & Doutt from Mexico, P. orientalis Taguchi from the Philippines (Taguchi, 1972), P. besucheti Viggiani from Sri Lanka (Viggiani, 1974), P. magnificum Yoshimoto from Canada (Yoshimoto 1990), and P. dictyon Hayat & Anis from India (Hayat and Anis 1999). Here we describe a new species of Ptilomymar from southwest China. A tentative key to species is provided based on their original descriptions. No types other than that of the new species were examined.

Materials and methods
Specimens were collected from Yunnan Province (southwest China) using yellow pan traps. Specimens were dissected and mounted dorsally or laterally in Canada balsam on slides following the method described by Noyes (1982) and modified for the Mymaridae by Huber (1988). Photographs were taken with a digital CCD camera attached to an Olympus BX51 compound microscope, and most measurements were made from slide-mounted specimens using an eye-piece reticle. Total body length excluding ovipositor was measured with an eye-piece reticle from alcohol-preserved specimens before being dissected. All measurements are given in micrometers (μm). Specimens studied are deposited in the following institution: NEFU Northeast Forestry University, Harbin, China.
Morphological terminology and abbreviations are those of Gibson (1997) and Huber (2012), as follows (with some additions):

OD
Mid ocellar diameter OOL Ocular-ocellar length LOL Least ocellar length POL Postocellar length Fl n Flagellar segment Gt n Gastral tergum

Results
Key to species of Ptilomymar of the world (based on features from the original descriptions and illustrations).
(Note: females are not known for orientalis; males are not known for dictyon and rete) Pedicel about 1.6× as long as fl 1 ; fl 1 distinctly longer than wide (Fig. 1); fore wing about 3.6× as long as wide, with a triangular dark brown marking behind marginal vein (Fig. 4) Scape distinctly enlarged ventrally in apical half (Fig. 10)  Diagnosis. Scape distinctly enlarged ventrally in apical half; pedicel about 1.6× as long as fl 1 ; fl 1 distinctly longer than wide; fore wing 3.62× as long as wide, with a triangular dark brown marking behind marginal vein, and a narrow brown strip just beyond venation; gt 1 with large translucent carinae; ovipositor distinctly exserted.
Ptilomymar dianensis is distinguished from most other species except P. magnificum by the shape of the scape that is distinctly enlarged ventrally in apical half (the scape not distinctly enlarged ventrally in apical half in the remaining species), P. dianensis differs from P. magnificum by its longer fl 1 (shorter in P. magnificum), wider fore wing (narrower in P. magnificum), and shorter metanotum, 0.25× as long as scutellum (longer metanotum, slightly less than 0.5× as long as scutellum in P. magnificum). P. dianensis differs from P. rete by its larger translucent carinae (smaller in P. rete) and distinctly exserted ovipositor (not distinctly exserted in P. rete). P. dianensis differs from P. orientalis by its branched spiracular setae on propodeum (unbranched spiracular setae in P. orientalis), wider fore wing (narrower in P. orientalis), and larger facets (smaller in P. orientalis). P. dianensis differs from P. besucheti and P. dictyon by its longer fl 1 (shorter in the latter two), wider fore wing (narrower in the latter two), distinctly exserted ovipositor (not exserted in P. dictyon), fl 3-8 almost subequal in length (fl 7 and fl 8 each distinctly shorter than fl 3-6 individually in P. dictyon).
Description. Female. Head dark brown with ocelli black. Antenna brown with fl 1 slightly lighter, scape and pedicel yellowish-brown. Mesosoma dark brown with pronotum and petiole brown. Fore wing hyaline, with a triangular dark brown marking behind marginal vein, and a narrow brown strip just beyond venation. Venation brown with stigmal vein dark brown. Legs yellowish-brown with last tarsal segments brown. Metasoma dark brown with ovipositor brown.
Head. Eye about 1.5× as long as wide; facets large, each nearly the size of an ocellus. Vertex 0.82× as long as wide, with strong reticulate sculpture; POL about 6.5× as long as OOL. Antenna (Fig. 1). Scape 5.45× as long as wide, longitudinally striate, distinctly enlarged ventrally in apical half; pedicel almost smooth, 1.31× as long as wide, and 1.55× as long as fl 1 ; fl 1 distinctly longer than wide; fl 2 slightly longer than pedicel, 1.64× as long as fl 1 ; clava 2.48× as long as wide.
Male. Similar to female except as follows. Antenna ( Fig. 10) with all the flagellar segments longer than wide. Fore wing (Fig. 11) 3.89-4.06× as long as wide. Hind wing (Fig. 12) 0.76-0.78× as long as fore wing, disc with only one row of setae.
Measurements ( Host. Unknown. Etymology. Chinese: dian=Yunnan Province, and refers to the distribution of the species in the Yunnan Province of China.