Aphelagathis verticalis (Cresson) Cresson, 2015

Sharkey, Michael J. & Chapman, Eric G., 2015, The Nearctic genera of Agathidinae (Hymenoptera: Braconidae) with a phylogenetic analysis, illustrated generic key, and the description of three new genera, Zootaxa 4000 (1), pp. 49-72 : 58

Aphelagathis verticalis (Cresson) NEW COMBINATION

( Fig. 2 ).

Microdus verticalis Cresson 1872

Notes. The type specimen of this species is lost. It was not found by Muesebeck (1927) for his revision of North American Agathidinae (as Braconinae), nor has it been discovered since, which is not unusual for Cresson types. In the University of Kentucky Collection there is a specimen of A. verticalis collected in 1894 and identified by Ashmead as Microdus verticalis . This specimen and others that appear to be conspecific with it fit the Cresson (1872) description very closely, including details on patches of melanic color, size, and sculpture. We therefore take the opportunity to designate a neotype for the species. The original type was collected in Texas by G.W. Belfrage, but no further information is included in Cresson’s (1872) original description. We do not have a series of specimens collected in Texas and since we believe it desirable to include COI barcode data, when possible, for type specimens we selected a recently collected specimen from Kentucky ( Fig. 2 ), rather than older specimens that are closer to Texas, e.g., Louisiana.

Presently we do not fully understand the limits of the species. As mentioned above, a series of specimens from Louisiana was reared from Ancyloxypha numitor , the least skipper. The distribution of the host extends from Florida in the southeast to east Texas and northwestern Mexico in the southwest, north to southeastern Saskatchewan and east to the Atlantic provinces of Canada. Presumably pale (mostly yellow), gracile specimens of Aphelagathis in this range belong to A. verticalis . The northern extent of specimens of A. verticalis in our possession is southern Ohio and Illinois, and we have seen no specimens from the northwestern range of the host. However any pale colored specimens captured in the Midwest or north will presumably belong to A. verticalis .

Difficulties in species delimitation begin in the southwest just outside the range of the host. In Arizona for example, there are specimens with similar coloration, size, shape etc. but which differ in subtle characters. We are presently barcoding many of these specimens and intend to revise the genus in the near future.

The following diagnosis will differentiate our present concept of A. verticalis , which excludes specimens outside of the range of the one known host.

Diagnosis. This is the only predominantly yellow species of Aphelagathis that resides in the middle and eastern regions of the USA. The only other relatively common species in the southeastern USA is undescribed; it is larger, and the head and mesosoma are entirely black. For specimens in the southwestern USA and Mexico the species limits are not clear, and resolution of this problem must await a molecular approach. This species is yellow except for black as follows: antenna, patch on dorsal region of head extending from antennal bases to inside ocellar triangle, apex of hind femur and apex of hind tibia, most of hind tarsus. The preceding is the most common color combination but specimens may also have black in the following areas: entire vertex and occiput, base of hind tibia, propleuron and anteroventral patch of pronotum. Black color on the body of the head may be completely absent, or absent except for small patches on the frons at the base of the antennae. Male specimens from southern Illinois (and Tennessee) are more melanic with the propodeum mostly to entirely black ( Fig. 2 b), first metasomal median tergite slightly darkened, and apical terga (5-8) mostly melanic. These specimens also have more extensive black on the head and mesosoma , but both the meso and metasoma are predominantly yellow in all specimens. A specimen from Tennessee has about 1/3 of the mesopleuron weakly melanic.

Material examined. Neotype ♀. USA, Kentucky, Hopkins Co., Thomas Farm, 37° 20.357N, 87°41.281’W, M[alaise]T[rap] 4: swamp 2, 13-29.ix.2010, H7739 ( HIC).

Other specimens: 34 specimens from the neotype locality are deposited in HIC as are 10 specimens from a swamp in southern Illinois and one specimen from Tennessee. Specimens collected in Florida are deposited in FSCA, UCFC and CAS. The series of specimens from Louisiana reared from Ancyloxypha numitor are deposited in the USNM.

Molecular data. H7463 ( COI: ATRMK 461-11); H7697 ( COI: ATRMK 434-11, 28S: KP943715 ); H7739 ( COI: ATRMK 458-11); H11323 ( COI: KP943636 ).

Figures

FIGURE 2. Aphelagathis verticalis. a. Lateral habitus (neotype ♀), arrow shows thickened area of ovipositor. b. Lateral head and mesosoma of melanic ♂ from Illinois. c. Dorsal habitus (neotype ♀), arrows show diverging carinae of propodeum and smooth first median tergite. d. Hind tarsal claw showing truncate basal lobe (neotype ♀). e. Wings, arrow shows nebulous Cub vein (neotype ♀). f. Lateral view of head and mesosoma (neotype ♀).