University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln

Center for Systematic Entomology, Gainesville, Insecta Mundi Florida

October 1986

Lithoserix williamsi (Siricidae: ) a newly recognized fossil from Florissant, Colorado

F. Martin Brown University of Colorado Museum

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Brown, F. Martin, "Lithoserix williamsi (Siricidae: Hymenoptera) a newly recognized fossil horntail from Florissant, Colorado" (1986). Insecta Mundi. 505. https://digitalcommons.unl.edu/insectamundi/505

This Article is brought to you for free and open access by the Center for Systematic Entomology, Gainesville, Florida at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Insecta Mundi by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Vol. 1, no. 3, October 1986 INSECTA MUNDI 119

Lithoserix williamsi (Siricidae: [Iynenogtera) a newly reco(jr1ized fossil horntail from Florissant, Colorado. F. Martin Brown Research Associate University of Colorado Museum A recently found fossil from the old The diagram of the left wing omits the Scudder pit (?) appears to be a large female venation of the hind wing which is confused horntail. It shows the ventral aspect. Con- with that of the anal rcargin of the forewing. pared with modern Siricidae, the length of About 15 mm of the wing's length is preser- its ovipositor in relation to the body proper ved. The wing tip is not preserved. There suygests nodern spectrum. Unfortunate- is a small but well defined dark stigma. The ly the venation is inconpletely preserved on n,ed.ian cell is large, measuring about 7 mnl both wings. In addition to this the fore- along the costal margin and 1.3 mm at its wings and hindwings overlap to some extent on greatest depth. It is a scalene triangle in each side. What venation is decipherable is shape. Cell cu+cul is subrectangular and consistent with that of the family as can be measures about 5.3 mm long x 1.0 mm at its seen in the two sketches. It does not seem widest point. Distad of this and continuing to agree with any of the modern genera ex- the direction of the veins is cell M3, 2.9 x an(ined but approaches that of more 1.1 nm in greatest dimensions. Between cell closely than any other. Both antennae are M3 and the stigma cells M4 and 1R1+R5 are not faintly indicated. They are stout, many- clearly separated. The vein M (or ,M1+2) segmented and in keeping with those of Siri- cannot be seen in its entirety. The missing cidae. Both hind legs are preserved faintly portion is represented by short dashes in the alniost throughout their length. They are diagram. The cross vein separating 1st M2 stout, and the individual segments are clear- cell from M1 cell is ill-defined, and only ly defined. the posterior half of it can be traced.

The total body length, omitting the A large flake of shale carried off most ovipositor, is 22 mm divided as follows: of the critical venation of the right fore- head 1 n;n, prothorax 3 mm, ~t~esothorax3.5 mm wing. More of the hind wing can be deciph- metathorax 2.5, 12 mm. The greatest ered on this side than on the left. At that width of the body is at the mesothorax, 4.3 only part of the anterior portion of the wing mm, but the dimension is not trustworthy is represented by well-defined veins. Only because the is sonewhat crushed. 4.3 that part of the venation involving the dis- and 4.5 mm of the left and right antennae are tal portion of the median cell and a portion preserved. The width is 0.4 mm. A segment of the wing apicad of that is clear enough in or two is well enough preserved to suggest the fossil to allow study. Most of the cross that the segments are about half again as veins are not visible. The fore and hind long as wide. The thoracic segnents suggest wings overlap, and in the drawing the fore- that the insect is on its back. There are wing veins have been omitted. very small finely striate sublateral areas, and there appear to be medial and nedio- The portion of the left forewing vena- lateral grooves. The latter may be an arti- tion that is visible is sufficiently cii;fer- fact of fossilization, folds instead of ent from that of any other and grooves. The abdominal segments, five in from either the fossil siricids described all, appear transversely banded dark and by Cockerell and by Rohwer to warrant a new light. The dark bands probably are the re- ge~~ericrlar,ie as well as a distinctive trivial mains of heavy chiton, the light ones more nan;e. he descriptions above anti the draw- delicate chiton connecting the somites. ings niay be take11 as description of both The ovipositor is incomplete,18.4 mm of genus and si:ecies, Lithoserix williamsi n.gen it are preserved. The termi- and n.5~. The provenience of the fossil is rial tab of the Sirici6 abdomen is very dark - Florissant Lake Shales, early Oligocene, composed of heavy =hiton - and measures 3.8 FlOriSsilnt, Teller CO., Colorado. It is the nm wide anteriorlyand 2 mm long. ~h~ property of the National Park Service, ovipositor tapers frombasal 0.6 mm to 0.4 mm Florissant Fossii Eeds rational Ilonunent. at its distal end. It has a thin ,,,idline Following regulations, it is deposited in the clearly visible onlyin the abdominad typ collection of the Uriiver sity Eluseurn, portion. University of Colorado, Eoulder, where so many Florissant fossils are preserved. The hind leg is at least 15 mm long. The following measurenents of the parts could The generic name, Lithoserix, is a crea- be made: coxa 0.9? x 0.6 mm, trochanter 0.3 x tion of convenience based on lithos a trans- 0.6 mm, femur 3.5 x 1.1 mm, tibia ca. 5 x 0.7 literation of the Greek word for stone and mm, tarsus 6 x 0.3 mn (individual joints not Serix the basic genus of the faixily to which well enough defined to measure). A trace of I assigned the fossil. The trivial nac:e, the foot appears to be visible on the right williamsi, cor?.menorates Jack I?illian!s, the side but too poorly preserved to warrant retired super intendent of the monument who description. eight years ago askeci me to make a detailed 120 INSECTA MUNDI Vol. 1, no. 3, October 1986

study of both the modern and fossil , of the area. The initial number of the fos- sil is FLFO 119 in the monument collecticn and now carries the UCN number 31179.

Sithoserix uilliamsi, n.sp., diagram of vanation of left forewing and \ \ right hind wing. " '"8