Penestola wichardi Solis, Leger & Neumann, 2023

Solis, M. Alma, Leger, Theo & Neumann, Christian, 2023, First pyraloid (Insecta, Lepidoptera) caterpillar from Dominican amber, Nota Lepidopterologica 46, pp. 145-154 : 145

Penestola wichardi Solis, Leger & Neumann sp. nov.

Figs 3 , 4-5

Type material.

Holotype. The holotype is a larva preserved in Dominican amber of mid Miocene age. It is located in the amber collection of the MfN, inventory number: MB.I 11433 (former Wichard amber collection) (Figs 3 , 4 , 6 ).

Condition.

Excellently (completely) preserved caterpillar (length 9.7 mm) exposing lateral, ventral, and dorsal views. Size of amber piece after preparation: 3.7 cm.

Diagnosis.

The holotype of Penestola wichardi differs by the absence of a pigmented spot at the genal angle of the head that occurs in Penestola bufalis (Figs 2 , 3 ).

Generic placement.

Penestola wichardi shares with the larva of the extant Penestola bufalis a setal number and a placement on pinacula for setae that can be observed. Most obviously, the holotype shares with P. bufalis , on the lateral view of the thoracic segments, a distinctive shape of the SV pinacula, a line thin anteriorly and broader posteriorly after the SV seta (Figs 2 , 3 ). On the abdominal segments, the D1 pinacula is round, the D2 pinacula is elongate, and the D2 seta is situated near the lateral edge of pinacula. On the abdominal segments on A1 they share 3 SV setae. Most especially distinctive is the shape of the SV pinacula, a line thin anteriorly and broader posteriorly after the SV seta (this character does not occur in this shape in other spilomeline genera examined). This character also occurs in another taxon in the tribe Steniini , Duponchelia fovealis Zeller, 1847, but this species was originally distributed in Europe, and is an exotic species introduced this century into the Western Hemisphere. We should note that the morphological description is not complete due to inability to observe some features in the fossil, for example, the dorsal pinacula on abdominal segments A7-A9, the exact crochet pattern on the proleg, and ventral setal patterns (see Hayden and Burnette 2022 for comparison to D. fovealis ).

Description.

Body: (Figs 3 - 6 ) Elongate, cylindrical with a distinct head, thorax, and abdomen. Head: Hypognathous, height and width subequal, sclerotized light brown; posterior margin of gena dark brown, pigmented spot at genal angle absent; epicranial suture, frontoclypeus, labrum, and mandible not visible (specifically, the frontoclypeal area of the head capsule is missing, probably damaged, and appears white in color rather than light brown); stemmata 1-5 visible, 1-2 dorsal, 3-5 posterior to antennal base, stemma 6 only slightly visible. Hypopharyngeal complex with aciculate spinneret, prementum only slightly visible. Maxillary palpus and antenna visible. Chaetotaxy difficult to see with the exception of the presence of P1 and the socket of P2 on the frontal area of the head. Thorax: T1 dorsally with black pinacula; SD1, XD1 and D1 present; XD2, D2 and SD2 sockets present (seta missing); sockets of L1, L2 present on a sclerotized pinaculum, extending slightly below spiracle; sockets SV1, SV2 present on sclerotized pinaculum, less wide anteriorly. Ventrally T1 with sockets of V1 visible on a single triangular pinaculum. T2 with D1, D2 present on the same pinaculum, circular to subrectangular; SD1 and SD2 sockets present; L1 and L3 present; L2 present on a separate pinaculum; SV1 present, less wide anteriorly. T3 with D1, D2 present on separate pinacula; SD1 present; SD2 socket present; L1 present, L2 socket visible; SV1 present, shorter than in T1 and T2 and less-wide anteriorly. Ventrally T2 and T3 with V1 setae on separate pinacula (shape variable due to preservation distortion). Abdomen: A1 with D1 and D2 present on separate pinacula; D1 at same level as D2; SD1 present; L1 present, L2 pore present, L3 not visible; SV setae present, one long, conspicuous seta and one thin, short seta; one long V seta. A2 with D1, D2 present; SD1 socket visible; L1 present, L2 socket visible; 3 SV setae present, one V seta. A3-A6 with D1, D2; SD1 present, clearly visible; L1, L2 present, L3 present on A5, A6; SV1, SV2, SV3 setae visible at base of proleg. Prolegs present. Crochets in a biordinal mesal penellipse. A7 with D1, D2 (setae on separate pinacula), SD1 present; L1, L2 pores present; SV1, SV2, SV3 setae visible. A8 with D1 and D2 on separate pinacula, although D1 does not appear to be directly on the pinacula which could be an artefact; SD1 present; sockets L1, L2 present; 1 SV seta. A9 with D1 present, possibly D2 also present, but difficult to see; SD1 pore visible; L1, L2 setae present; 1 SV seta. A10 with D1, D2 setae present; SD1 present; L1, L2 setae present; SV1 present.

Remarks.

The putative placement of this fossil in the Crambidae is based on a unisetose (sometimes bisetose) L group on A9, crochets in an incomplete circle (penellipse), and, most specifically, the lack of a pinaculum ring at the base of SD1 on A8 or any other segments ( Hasenfuss 1960; Neunzig 1987) which is present in the Pyralidae . Although Allyson (1984) was unable to find specific larval characters to define the subfamilies Pyraustinae and Spilomelinae , she noted that many Spilomelinae have the pinacula with setae D and SD fused (this larva does not have D and SD fused as in, for example, Nomophila , Udea , Desmia ), and the pinaculum bearing SD1 reduced in abdominal segments 2 and 7, a character that is exhibited by this fossil larva.

The extant Penestola bufalis species (Fig. 2 ), which the fossil caterpillar resembles, is distributed throughout the Western Hemisphere, from Florida and Mexico south to northern South America and islands in the Caribbean, including the Dominican Republic, where its habitat consists of coastal mangrove swamps and shorelines. The Miocene forest biome producing Dominican amber has also been interpreted as a coastal (periodically flooded) swamp forest, as indicated by the occurrence of marine biota such as boring bivalves of the family Pholadidae ( Mayoral et al. 2020).

Etymology.

It is named in honor of the palaeoentomologist Wilfried Wichard (Bonn) who donated the specimen.

Figures

Figures 2, 3. Lateral view of larval head and thoracic segments. 2. Penestola bufalis (Guenee, 1854) (NMNH); 3. Penestola wichardi Solis, Leger, and Neumann, sp. nov., holotype (MfN).

Figures 4 - 6. Penestola wichardi Solis, Leger, and Neumann, sp. nov. holotype, preserved in Dominican amber. 4. Ventral view; 5. Setal chart based on lateral view; 6. Lateral view.