Morphological characters
Certain characters were chosen to test morphological reasoning for placement of the fossil species. The character matrix can be accessed on Dryad Data Repository (DOI https://doi.org/10.6086/D19098). Some features that could not be assessed on the fossil were chosen to ensure that subfamily monophyly resembled that of recent phylogenies (Gauthier et al. 2000; Burks et al. 2011; Gumovsky 2011; Heraty et al. 2013).
1. Antennal flagellomere formula excluding anelli (in format of funiculars, clavomeres): 0 = 6,1; 1 = 6,2; 2 = 2,3 (Fig. 4C); 3 = 5,3; 4 = 3,1; 5 = 3,3 (Fig. 4A); 6 = 4,2 (Fig. 4B).
Flagellomere count proved to be problematic to assess, due to a poor visible distinction between having one or more anelli in Tetrastichinae and Opheliminae. However, it was observed that some taxa possessed an almost constant count of funiculars and clavomeres beyond the anelli. Funiculars are loosely articulated segments between the anellus and clava, whereas the clava is comprised of closely appressed and immobile terminal segments (Heraty et al. 2019). The combination of funiculars and clavomeres were necessary to separate Cirrospilini from Tetrastichinae. Members of Cirrospilini have 2 funiculars and 3 clavomeres or 3 funiculars and 2 clavomeres (Fig. 4C, D), whereas members of Tetrastichinae have 3 funiculars and 3 clavomeres (Fig. 4A). The formula was coded only for females, because many Eulophidae are sexually dimorphic for this character, generally possessing one additional funicular in males.
2. Antennal flagellomere count beyond anelli: coded as actual count.
This character is the raw count of funiculars plus clavomeres, regardless of their arrangement.
3. Frontal sulci of head: 0 = with a complex of sulci: V-shaped connecting to scrobal sulci, but not connecting to ocs (Burks et. al. 2011, fig. 18); 1 = without sulci; 2 = with a single transverse sulcus near mid-height of face (Gauthier et al. 2000, fig. 8D); 3 = scrobal sulci merging and proceeding to a small curved sulcus immediately ventral to ocellar triangle (Fig. 5A); 4 = with a complex of sulci: V-shaped connecting to scrobal sulci and connecting to a sulcus encircling the ocellar triangle (Fig. 5B).
Exact homology of frontal sulci proved difficult to establish with certainty, but particular classes of sulci could be established. State 1 occurs mainly in Entiinae, with sporadic and presumably homoplastic appearances in other subfamilies. State 2 occurs in most Cirrospilini but not in other eulophids (Gauthier et al. 2000). State 0 occurs in many Entedonini, where a V-shaped sulcus is often present distant from the ocelli. State 4 occurs in many Tetrastichinae (LaSalle 1994). The scrobal sulci in Tetrastichinae are separated in a few taxa, such as Crataepus Förster and Pronotalia Gradwell, but the parascrobal areas of most tetrastichines seem to be enlarged and meeting medially to conceal the median areas from view (LaSalle 1994). This feature could not be seen in the fossil species due to face collapse, but a collapsed face is expected to occur only in taxa that have frontal sulci.
4. Propleuron shape: 0 = posteriorly angular (Gauthier et. al. 2000, fig. 7B); 1 = posteriorly straight (Gauthier et. al. 2000, fig. 7A).
State 1 was reported by Gauthier et al. (2000) as diagnostic for most Eulophini. This state also occurs in presumably unrelated taxa such as the pteromalid subfamily Cerocephalinae, but nearly all other chalcidoids possess state 0.
5. Prepectus dorsal length: 0 = same length or shorter than acropleuron; 1 = longer than acropleuron (Fig. 1E).
The fossil species was observed to have a large prepectus. While this is a homoplastic feature throughout Eulophidae, it was coded because it was one of the few distinctive features of the fossil species. Most Eulophidae have a smaller prepectus, but large-bodied species are likely to have a larger prepectus relative to the surrounding sclerites. The acropleuron was chosen for this comparison because in Eulophidae it is near the prepectus and relatively uniform in relative length.
6. Mesothoracic spiracle visibility: 0 = exposed to view externally (Fig. 3D); 1 = concealed by pronotum and mesoscutum (Gumovsky 2011, fig. 6F).
Gumovsky (2011) used state 1 to help define the tribe Entedonini. Most other Eulophidae, and most other Chalcidoidea, have an exposed mesothoracic spiracle, although Anselmella Girault (Anselmellini, currently unplaced within Eulophidae) was also observed to have a concealed spiracle.
7. Mesoscutellar submedian grooves: 0 = absent (Fig. 3F); 1 = present (Fig. 3E).
Various Eulophidae have submedian grooves (occurring medial to the paired mesoscutellar setae), a feature found in almost no other Chalcidoidea. The mesoscutellum was not easily visible in the fossil species, but this feature was coded to help separate taxa that lack these grooves, such as Entiinae and Opheliminae, from taxa that generally have them. These grooves are posteriorly subparallel in taxa such as Cirrospilini and most Tetrastichinae. A U-shaped, posteriorly-meeting groove (state 1) (Burks et. al. 2011 fig. 26) is shown to be autapomorphic according to our matrix, and present only in Elachertus cacoeciae Howard (Eulophini).
8. Transepimeral sulcus presence: 0 = absent (Fig. 5D); 1 = present (Fig. 3A–D).
The transepimeral sulcus was one of the few reasonably distinctive features of the fossil species that could be assessed without doubt. While nearly all eulophids have a transepimeral sulcus, Anselmella and the outgroup species Foersterella erdoesi Bouček (Tetracampidae) do not.
9. Transepimeral sulcus shape: 0 = arched or sinuate and extending dorsoventrally (Fig. 3C); 1 = arched or sinuate and extending anteroposteriorly (Fig. 3D); 2 = straight (Fig. 3A, B).
A strongly curved transepimeral sulcus was found to separate many Eulophinae from many Tetrastichinae, with few exceptions. In the two Entedonini coded, the transepimeral sulcus extends posteriorly from near the middle of the mesopleural sulcus, which was coded as a characteristic 10, transepimeral sulcus junction with mesopleural sulcus, state 1 because of its difference in connection of the sinuate sulci in other taxa. Inapplicable characteristics, where no sulcus was present were coded as “?”.
10. Transepimeral sulcus junction with mesopleural sulcus: 0 = meeting at mesocoxal insertion (Fig. 3A); 1 = meeting far dorsal to mesocoxal insertion (Fig. 3D).
The junction of the transepimeral sulcus with the mesopleural sulcus was shown to be an interesting feature to help differentiate eulophid subfamilies. While this character is homoplastic across Eulophinae and Tetrastichinae, state 0 was unequivocally present in the fossil species, and therefore this character was used to help place it. Taxa without a sulcus were coded as “?”.
11. Admarginal setae presence: 0 = present (Fig. 2A, B); 1 = absent.
Admarginal setae are located immediately posterior to the fore wing marginal vein and are frequently longer than the surrounding dorsal and ventral setae. Most Eulophidae have these setae, but they are absent in a few, presumably derived, species.
12. Admarginal setae length: 0 = long (Graham 1959 fig. 9); 1 = short (Fig. 2A, B).
The distinction of admarginal setae occurs mainly in two ways, either by being very different in length relative to surrounding setae, or by their isolation. In many Eulophidae, the admarginal setae are much longer than most other fore wing setae. Both states occur in other Chalcidoidea, with state 1 being arguably the most frequent. Taxa without admarginal setae were coded as “?”.
13. Number of rows of admarginal setae: 0 = more than one row (Fig. 2A, B); 1 = one row (Graham 1959, fig. 9).
In many Eulophinae, long admarginal setae are present in only one row. This is also the case in taxa where the admarginal setae arise in part from the ventral surface of the marginal vein, such as Opheliminae. When multiple rows are present, they may occur irregularly as 2 or 3 rows, sometimes with the two fore wings differing. Taxa without admarginal setae were coded as “?”.
14. Cubital fold shape: 0 = straight or only slightly curved (Graham 1959, fig. 7); 1 = strongly curved near basal fold (Graham 1959, fig. 6).
A strong curvature of the cubital fold, and of its corresponding setal track, is known in Cirrospilini (Graham 1959). It proves diagnostic for many members of the tribe, although some species possess only a mildly curved cubital fold.
15. Parastigma connection: 0 = smooth (Graham 1959, fig. 5); 1 = abrupt (Graham 1959, figs 8–9).
The abruptness of the connection of the parastigma with the marginal vein has often been used to identify Eulophini (Graham 1959), although we found it to be difficult to assess in many species.
16. Postmarginal vein length: 0 = as long or longer than stigmal vein (Fig. 2A, B); 1 = shorter than stigmal vein (LaSalle 1994, figs 129–130).
The postmarginal vein is variable in length in Eulophidae, although a majority of taxa possess either state 0 or state 1. While most Tetrastichinae have state 1, Peckelachertus Yoshimoto and Quadrastichodella Girault have state 0.
17. Tarsomere count in females: 0 = 5; 1 = 4.
The number of tarsomeres in females is diagnostic for Eulophidae, with four tarsomeres instead of the usual five. This character separates the outgroup species F. erdoesi (Tetracampidae) from the ingroup Eulophidae.
18. Propodeal callus setae: 0 = 10 or more setae (Fig. 4F); 1 = 0 to 9 setae (Figs 4E, 5C).
Larger numbers of propodeal callus setae are present in most Eulophini. Additional states were initially coded for taxa with a smaller number of propodeal callus setae, but these proved to be more difficult to treat consistently and thus were collapsed into state 1.