Thyreodon morosus, SMITH, 1879

Gauld, Ian D. & Janzen, Daniel H., 2004, The systematics and biology of the Costa Rican species of parasitic wasps in the Thyreodon genus-group (Hymenoptera: Ichneumonidae), Zoological Journal of the Linnean Society 141 (3), pp. 297-351 : 319-320

5. THYREODON MOROSUS SMITH

Thyreodon morosus Smith, 1879: 230 . Holotype ♀, COSTA RICA (BMNH) [examined].

Thyreodon pulchricornis Szépligeti, 1906: 133 . Lectotype ♀, PERU, designated by Townes & Townes, 1966: 190 (TM) [examined].

Fore wing length 20.7–22.6 mm; clypeus convex, with apex strongly pointed medially and conspicuously flared outwards; malar space about 0.5 times basal mandibular width; maxillary palp long with second palpomere broadened and flattened; lower face centrally coarsely punctate; frons with a pair of dorsally divergent crests between antennal sockets and with a sharp carina extending from outer rim of antennal sockets upwards, close to and parallel with eye margin; frons centrally weakly rugose; ocelli small, the lateral ocellus separated from eye by about 1.3 times its own maximum diameter; head in dorsal view punctate, with gena rather evenly rounded behind eye, occipital carina strong, its lower end sharp, abruptly in-turned but not reaching hypostomal carina; antenna setaceous, with 58–62 flagellomeres, the 20th slightly transverse, 0.9 times as long as broad, the subapical ones with setae which are shorter than the diameter of the flagellomere. Pronotum short with anterior margin strongly and broadly reflexed, and with posterior margin centrally swollen, with a sharp forward projecting ridge which is separated from the anterior margin by a deep U-shaped groove ( Fig. 25 ); epomia weak but discernible on upper part of pronotum; propleuron sparsely punctate, slightly convex, with lower corner flattened but not peripherally impressed; mesoscutum finely punctate, with broad, shallow, reticulated notauli which are confluent posteriorly, inner anterior margin of notaulus forming a low, longitudinal ridge; scuto-scutellar groove very deep, laterally margined by a very strongly raised, simple carina; scutellum punctate, convex; mesopleuron moderately closely and rather coarsely punctate, with a shallow sternaular impression; metapleuron finely rugose; propodeum laterally slightly flattened, coarsely diagonally striate, with a sharp ridge above and behind the spiracle; propodeum transversely rugose posterolaterally, centrally with a single shallow longitudinal impression. Fore leg of female rather stout, with coxa with a bluntly rounded protuberance behind trochanteral insertion, with 5th tarsomere about 0.8 times as long as preceding two tarsomeres, with tarsal claw long and with close pectinae; hind coxa in profile moderately small, its hind end more or less level with hind end of propodeum; hind femur slender, about 6 times as long as maximally deep; hind tarsus of male with moderately dense, short pubescence ventrally. Fore wing with abscissa of Cu 1a between Cu 1b and 2 m-cu 0.7–0.8 times as long as abscissa of Cu 1 between cu-a and 1 m-cu. Metasoma with tergite I slender, anteriorly slightly laterally compressed; tergite II, in lateral view, 2.6–2.7 times as long as posteriorly deep. Male with subgenital plate small and convex, covered with dense coarse black hair; claspers quite long, the dorsal distal apex obliquely truncate, the lower margin sharply angulate near apex, so apex can appear to have a broadly Vshaped indentation; dorsal margin with a deep median notch, basally slightly expanded ( Fig. 59 ); aedeagus in profile with apex up-turned, weakly inflated, rounded.

A black species with proximal 0.6 or more of flagellum yellowish white; wings uniformly blue-blackish infumate.

Remarks: Thyreodon morosus closely resembles two sympatric species, T. erythrocera and T. walkerae , which are also black with black-tipped yellow-white antennae ( Fig. 5 ). (NB in all these species of Thyreodon , the yellow antennae fade to a substantially lighter creamy white colour in museum specimens.) The black-tipped yellow-white antennae alone are sufficient to distinguish these species from all other Thyreodon in Costa Rica, but in the past (e.g. Porter, 1984) the three species have been confused under the name T. morosus . The true T. morosus differs from the other two species in having the propodeum, in lateral view, with very coarse diagonal striae, and having a more or less sharp longitudinal ridge above and behind the spiracle. In the other two species the propodeum is finely reticulate laterally, and there is no trace of longitudinal ridge dorsally ( Fig. 29 ). T. morosus also has the mesopleuron more coarsely punctate than do the other species, and the metapleuron is more rugose. The caterpillar host of T. morosus is also probably different from that of the other two species (see below).

Biological notes: Thyreodon morosus is a widespread species that at very least ranges from Costa Rica south to Peru. The few records we have suggest it is primarily found in low- to mid-altitude rain forests. Porter (1984) recorded it from as far north as Yucatan in Mexico, but these records require verification as the species was frequently confused with other taxa, and it does not occur in Costa Rican dry forest with a climate similar to those of Yucatan. It is widely distributed in Costa Rican rain forest. Although this species occurs well within the area of the ACG caterpillar rearing programme, it has not yet been encountered in many thousands of caterpillars and many tens of sphingid species reared from these rain forest sites.

Material examined: Holotype ♀, COSTA RICA, Cartago Prov., Cachí (Rogers) ( BMNH) . Lectotype ♀, ( T. pulchricornis ) PERU, Marcapata , 1000 m ( TM) .

Non-type material: COSTA RICA: Guanacaste Prov.: 1 ♀, Guanacaste National Park, Estacion Cacao [= Mengo], 1000 m, vi.1987 (Janzen) (BMNH); 3 ♂, Guanacaste National Park, Estacion Pitilla, 9 km S Sta Cecilia, 700 m, iii–iv.1989 (Biodiversity Survey) ( INBio ); 1 ♂, Guanacaste National Park, Estacion Pitilla, 9 km S Sta Cecilia, 700 m, ix.1991 (Rios) ( INBio ): Puntarenas Prov.: 1 ♀, Monteverde, Estacion Brenes, 1300 m, vi.1991 (Bello) ( INBio ); 2 ♀, Monteverde, San Luis, 1040 m, ix–x.1992 ( Fuentes & Quesada ) ( INBio ); 1 ♀, Osa Peninsula, Corcovado National Park, 10– 100 m, iii.1982 (Janzen & Hallwachs) ( INBio ); 1 ♂, Osa Peninsula, Rancho Quemado, 200 m, xii.1991 ( Quesada ) ( INBio ); 1 ♂, Sitio Tinieblas, 2 km NE de la Tigra, 1440 m, v.1996 (Navarro) ( INBio ).

Figures

Figures 21–26. SEM photographs of Thyreodon spp., pronotum, lateral; 21, T. whitfieldi; 22, T. laticinctus; 23, T. darlingi; 24, T. rivinae; 25, T. morosus; 26, T. walkerae.

Figures 53–63. Apex of metasoma and male genital capsule, lateral; 53, T. maculipennis; 54, T. erythrocera; 55, T. whitfieldi; 56, T. laticinctus; 57, T. zitaniae; 58, T. papei; 59, T. morosus; 60, T. schauffi; 61, T. darlingi; 62, T. rufothorax; 63, T. atriventris.

Figures 3–6. Thyreodon species, whole insects, lateral, showing major colour patterns found in the genus. 3. T. atriventris. 4. T. laticinctus. 5. T. walkerae. 6. T. schauffi. Scale bar = 5 cm.

Figures 27–32. SEM photographs of propodeum lateral. 27, Thyreodon darlingi; 28, T. morosus; 29, T. walkerae; 30, T. zitaniae; 31, T. rivinae; 32, Rhynchophion flammipennis.