Thereus brocki Robbins, Heredia & Busby

Robbins, Robert K., Heredia, Maria Dolores & Busby, Robert C., 2015, Male secondary sexual structures and the systematics of the Thereusoppia species group (Lepidoptera, Lycaenidae, Eumaeini), ZooKeys 520, pp. 109-130 : 120-123

Taxon classification Animalia Lepidoptera Lycaenidae

Thereus brocki Robbins, Heredia & Busby sp. n. Figs 4, 8, 12, 18, 22, 24

Type material.

Holotype: ♂ (Fig. 4). [printed and handwritten on white paper] 28 June 1980/25 km. n. e. of Puyo,/Prov. Pastaza, Ecuador/leg. Jim P. Brock [printed on green paper] GENITALIA No./2013: 56♂/R. K. ROBBINS [printed white barcode label] USNM ENT 00181942 [printed label on red paper] Holotype/ Thereus brocki /Robbins, Busby, & Heredia. Deposited USNM.

Paratype

(1♀). Ecuador. 1♀ (Fig. 4). Napo, 14 km Tena-Puyo Road, Apuya, 01°06.7'S, 77°46.9'W, 600 m, 10 Sep 2010, (RCB).

Other specimens

(1♂,2♀). Colombia. 1♀. Vaupés, Mitú, 28 Jun 1972 (USNM). Peru. 1♂ San Martin, Juanjuí, 7°11'S, 77°44'W, 300-400 m, Nov 2011 (MUSM, examined from an image). 1♀. Huánuco, Tingo María, 800 m, 24 Jun 1982 (USNM).

Etymology.

This species is named for James Brock of Tucson, Arizona. He collected the holotype and has made numerous contributions to the knowledge and enjoyment of butterflies. The name is a masculine noun in the genitive case.

Type locality.

The type locality has been a well-known collecting site for 40 years at about 975 m elevation (noted in Brown 1979 with coordinates 01°20'S, 77°55'W, but incorrectly placed in Napo Province). The entrance to this locality is approximately 25 km (measured by a car odometer) from Puyo on the western side of the Puyo-Tena Rd. New metal road markers have been erected which place the entrance between km 26 and km 27. The trees in this location have been selectively logged for decades, and we do not believe much forest remains.

Diagnosis and description.

Thereus brocki belongs to Thereus because it possesses the synapomorphies of the genus (Figs 18, 24). It belongs to the Thereus oppia species group (Figs 4, 12). It shares a dorsal forewing scent pad with Thereus lomalarga (Figs 6, 8), but differs in having a gray-brown scent patch on the dorsal hindwing without iridescence and in possessing erect piliform setae on the inner margin of the ventral forewing (Fig. 4). The male lacks evident teeth on the dorsal tip of the penis (Fig. 18), which distinguishes it from Thereus lomalarga and Thereus oppia . The female of Thereus brocki is very similar to that of Thereus lomalarga , but differs in having more orange-red scales on the ventral hindwing at the anal lobe (Fig. 4). The wing pattern, androconia, and genitalia are illustrated (Figs 4, 8, 12, 18, 22, 24). Forewing size of the holotype male is 0.9 cm and of two females is 1.1 cm and 1.2 cm.

Female.

The female paratype of Thereus brocki is associated with the male by the shape similarity of the ventral hindwing postmedian line and by their capture approximately 30 km apart. Although the females of Thereus brocki and Thereus lomalarga illustrated in Figs 2 & 4 would seem to be distinguishable phenotypes, wing pattern variation in the extensive type series of the latter encompasses both phenotypes. For this reason, we restricted the paratype series. We unsuccessfully tried to extract DNA sequences from Thereus brocki to confirm the identification of the females.

Sexual dimorphism.

Forewing discal cell length in the male of Thereus brocki (Fig. 12) is shorter than in the female.

Distribution

(Fig. 26). Eastern Colombia to eastern Peru. It is allopatric with its phylogenetic sister, Thereus oppia .

Habitat.

Thereus brocki has been recorded only from wet forest up to about 1,000 m elevation.

Remarks.

The holotype and the Peruvian male are the only males in collections, so far as we are aware. The type locality has been a “famous” collecting locality for decades, as noted, so it is somewhat unexpected that the holotype remains the only known Ecuadorian male. It would appear that adult males of Thereus brocki , like those of Thereus lomalarga , are rarely encountered by insect collectors. Although we have an image of the Peruvian male (discovered late in the publication process), we have not had an opportunity to examine it. It is identified as Thereus brocki because it has the shortened forewing discal cell of the holotype and the same male wing secondary sexual traits, except that the erect piliform setae are not visible in the image. For this reason, we exclude it from the type series.