Chonocephalus Wandolleck, 1898
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publication ID |
https://doi.org/ 10.1080/00222930410001708680 |
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persistent identifier |
https://treatment.plazi.org/id/1F6887D7-3A27-4B4E-FE4A-FCE602ECC4D2 |
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treatment provided by |
Felipe |
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scientific name |
Chonocephalus Wandolleck, 1898 |
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Genus Chonocephalus Wandolleck, 1898 View in CoL View at ENA
Type species. Chonocephalus dorsalis Wandolleck, 1898, p 428 .
The genus is readily identified in the most recent key to world genera ( Disney 1994), with the modification that the genus Epichonocephalus Schmitz was synonymized with Chonocephalus in my recent revision, which provides a detailed diagnosis of the genus in both sexes ( Disney 2002). The wings of the males are distinctive ( Figure 40 View Figure 40 ) as is the general appearance of the females ( Figure 32 View Figures 32, 33 ).
Males
The recognition of species depends primarily on the details of the hypopygium, which is at first sight very complex. However, if one ignores the, often elaborate, penis complex (X), the details of the epandrium (E) and hypandrium (H) that are referred to in the key below are indicated in Figure 1 View Figure 1 . This represents a generalized, stylized, hypopygium. While the anal tube (A) is not utilized in the recognition of species it is a useful point of reference. Any one of the labelled structures may be modified and may sometimes be very elaborate in form. In the inferred groundplan state the rear margin of the hypandrium bears four processes. These are the gonopods (g) and a pair of median lobes (l). In the plesiomorphic state the gonopods articulate with the dorsal face of the hypandrium, but more frequently they arise from it. One (usually the left) or both may be reduced or absent. The median lobes (l) may form a single bilobed structure or be reduced to a single lobe (which may be greatly elongated) or be lost altogether. Ventrally each side of the epandrium (E) typically bears an anterior process (a) and a posterior process (p). In some species the anterior processes (a) may appear to be appendages (attaching to the inner face of the epandrium) rather than simple projections of the epandrium. A presumed true left surstylus or clasper (c) is frequently present (e.g. Figure 18 View Figures 18–20 ), variably fused to the epandrium, and is sometimes elaborate. Occasionally it is fused to the bridge (b), which is sometimes present and probably represents sternite 10. The most anterior (lower) bristle of the left side of the epandrium is sometimes modified into a spine (s), which may be further modified.
Key to males of Afrotropical species
1 Right gonopod with stem preceding swollen tip about four times as long as latter ( Figure 46 View Figure 46 )......................................... hibisci Paulian View in CoL
– Right gonopod clearly shorter..................................... 2
2 Right gonopod as Figure 50 View Figures 47–50 . Left gonopod as Figure 49 View Figures 47–50 . Left epandrial process is a long rectangle ( Figure 47 View Figures 47–50 ) whose posterobasal region attaches to the tip of the posterior arm of the large T-shaped right process ( Figure 48 View Figures 47–50 ) to form a complex bridge. The true bridge (b) is only sclerotized in the left two-thirds ( Figure 47 View Figures 47–50 ).................................................... justini View in CoL sp. nov.
– Not so..................................................... 3
3 The lowest bristle on left side of epandrium (S in Figure 1 View Figure 1 ) is differentiated as a strong spine and brown left surstylus is present (C in Figure 1 View Figure 1 ) ( Figures 14 View Figures 14–17 , 18 View Figures 18–20 , 59 View Figures 59–62 ).... 4
– Bristle S is not differentiated and left surstylus absent.................... 7
4 Bristle S of left side of epandrium stands at base of a dark brown, bare, leaf-shaped process ( Figure 14 View Figures 14–17 ). Other details of hypopygium as Figures 15–17 View Figures 14–17 ... collini Disney View in CoL
– Without this dark process associated with bristle S....................... 5
5 Right lobe of hypandrium long and tapering to a dark brown pointed tip ( Figure 19 View Figures 18–20 )..................................... cummingae View in CoL sp. nov.
– Right hypandrial lobe shorter, broader and not tapered to a darker pointed tip ( Figures 13 View Figures 10–13 , 62 View Figures 59–62 )............................................... 6
6 Right gonopod with spine-like bristles as Figure 61 View Figures 59–62 , otherwise bare. Thumb-like posterior lobe of left side of epandrium with fine hairs to tip ( Figure 59 View Figures 59–62 ).................................................... steineri View in CoL sp. nov.
– Right gonopod with different spines and numerous fine hairs ( Figure 13 View Figures 10–13 ). Thumblike posterior lobe of left side of epandrium bare between fine hairs at base and longer ones at tip ( Figure 10 View Figures 10–13 )......................... cautus View in CoL sp. nov.
7 Hypandrial lobes and left gonopod reduced to short brown lobes that are at most as long as broad ( Figures 23 View Figures 23–25 , 52 View Figures 51, 52 ) and the brown right gonopod is a long process tapering to a point ( Figures 24 View Figures 23–25 , 51 View Figures 51, 52 )....................................... 8
– Gonopods and hypandrial lobes otherwise............................. 9
8 Epandrial processes as Figure 23 View Figures 23–25 , the left anterior process having a small process towards its base.................................... depressus Meijere View in CoL
– Epandrial processes as Figure 51 View Figures 51, 52 , the left process having a small dark ridge running backwards from its base......................... madagascariensis Paulian View in CoL
9 Left side of epandrium with at least 10 hairs ( Figures 4 View Figures 4–7 , 29 View Figures 28, 29 , 30 View Figures 30, 31 , 34 View Figures 34–36 , 41 View Figures 41, 42 )...... 10
– Left side of epandrium with fewer than 10 hairs ( Figures 53 View Figures 53–56 , 57 View Figures 57, 58 )........... 13
10 The microtrichia of the left side below the hairs are modified into pointed scales (m in Figure 4 View Figures 4–7 ). Gonopods and lobes of hypandrium as Figures 5–7 View Figures 4–7 ....... ........ ................................................... americanus Borgmeier View in CoL
– Microtrichia of left side near margin absent and nearest ones are not modified. Details of gonopods and lobes of hypandrium otherwise ( Figures 28–31 View Figures 28, 29 View Figures 30, 31 , 36 View Figures 34–36 , 41 View Figures 41, 42 )...... 11
11 Bridge (b in Figure 1 View Figure 1 ) in form of distinctive horseshoe shape ( Figure 34 View Figures 34–36 ). Gonopods as Figure 36 View Figures 34–36 ......................................... fletcheri Schmitz View in CoL
– Bridge not of this form. Gonopods otherwise ( Figures 28–31 View Figures 28, 29 View Figures 30, 31 , 41 View Figures 41, 42 )........... 12
12 Right gonopod asymetrically expanded distally and with the longer arm directed rearwards and likewise the right process a of the epandrium; and left gonopod a long narrow process bearing a pair of bristles at its slightly expanded tip ( Figure 41 View Figures 41, 42 )........................................ heymonsi Stobbe View in CoL
– Right gonopod otherwise and left gonopod much more robust and with a single bristle at its tip ( Figures 28–31 View Figures 28, 29 View Figures 30, 31 ). Right process a of epandrium similar. dominicanus Borgmeier View in CoL
13 The two to three most anterior bristles on each side of epandrium are distinctly smaller than the rest and right side of epandrium with processes as Figure 57 View Figures 57, 58 ....... ....................................................... pudicus View in CoL sp. nov.
– The two to three most anterior bristles on each side of epandrium not differentiated from the rest and right side of epandrium with processes as Figure 54 View Figures 53–56 ....... ...................................................... modestus View in CoL sp. nov.
Females
The morphology of the females has been discussed elsewhere ( Disney 1986, 2002). It was concluded that the first, long, abdominal tergite is a composite of T1+T2 fused together, and that the last, also relatively long, fully developed tergite is T7 ( Figure 32 View Figures 32, 33 ). The microtrichia, lying between the hairs on these tergites, are frequently reduced in size and consequently tend to be more densely packed (cf. Figures 38, 39 View Figures 38, 39 ). Otherwise the taxonomically useful features are mainly the form and size of the modified abdominal tergite (T8) and sternite 8 (S8), the internalized sternite 9 (furca) and the spermatheca. Typically the remnants of T9 are variably fused to the anterolateral apodemes of T10. These structures are most fully developed in C. blackithorum ( Figures 2, 3 View Figures 2, 3 ). The form and dimensions of sternite 8 have proved to be especially valuable taxonomically. This sternite has seemingly evolved from an isosceles triangular sternite whose anterior end continues internally as an anteriorly directed apodeme (e.g. Figure 3 View Figures 2, 3 ). In many species the external sternite is greatly reduced or lost while the internal apodeme has increased in length. In some species a small sternite is retained as an externally visible projection (e.g. Figure 9 View Figures 8, 9 ). Tergite 8 is frequently reduced or seemingly absent. In the latter case it is present but only very lightly pigmented. Its presence may be discerned in many such cases by locating a minute hair at each posterolateral corner (e.g. Figure 8 View Figures 8, 9 ). However, these hairs are sometimes absent. There can be some confusion between the furca and spermatheca. Both are subcircular structures lying close to each other between T8 (when present) and S8. The spermatheca is typically a lightly pigmented bowl-shaped structure, as in C. blackithorum (Sp in Figure 3 View Figures 2, 3 ) while the furca is hoop-shaped and paler (S 9 in Figure 2 View Figures 2, 3 ). However, in many species one or other or both of these structures may be very pale and it may require critical adjustment of the microscope’s lighting in order to discern them both. In observing a female mounted on a slide with its dorsal side uppermost, as one focuses downwards the sequence of encounter is T8–furca (S9)–spermatheca–S8 (e.g. Figure 26 View Figures 26, 27 ). Where an egg is in place ready for laying, then it lies below T8 and the furca but above the spermatheca and S8. Indeed, the furca is often displayed to view most clearly against the background of such an egg. When no egg is in this position the furca may be tilted sideways on (as viewed from above or below).
Key to females of Afrotropical species
It should be noted that abdominal tergite 3 (T3) is the second apparent tergite as T1 is vestigial or fused to T2.
Caution: these keys to females not only include species given code letters only (until they can be linked to their males) but omit several species, as the number of these coded females is smaller than the number of species still only known in the male sex.
1 Microtrichia, between the hairs, on frons as strongly developed as those on abdominal tergites and not so densely packed (e.g. Figure 39 View Figures 38, 39 ). Without obvious submarginal dark bands at rear of abdominal tergites. Tip of sternite 8 (S8) and spermatheca as Figure 9 View Figures 8, 9 ...................................... americanus Borgmeier View in CoL
– Microtrichia on frons much smaller and more densely packed than those on T1+2–T6 or else they are small and dense in both situations (e.g. Figure 38 View Figures 38, 39 ). Without other features combined............................................. 2
2 T1+2–T6 with submarginal dark bands at rear margins (e.g. Figure 32 View Figures 32, 33 )........ 3
– No such dark bands (S8 as Figure 37 View Figure 37 )..................... fletcheri Schmitz View in CoL
3 T3 with less than 20 hairs (most arising from pale spots) at rear margin (e.g. Figure 32 View Figures 32, 33 )........................................................ 4
– T3 with more than 20 hairs at rear margin (e.g. Figure 43 View Figures 43–45 )................ 6
4 Microtrichia of T1+2–T6 a little longer and less dense than those on thoracic notum .......................................................... 5
– These microtrichia as small and as dense as those on thoracic notum.......... 6
5 T8 more strongly developed and furca a simple ring ( Figures 21, 22 View Figures 21, 22 ). Hind tarsus with ventral hair palisade on basitarsus only................... cummingae View in CoL sp. nov.
– T8 weaker and furca more complex ( Figure 33 View Figures 32, 33 ). Hind tarsus with ventral hair palisade on first two segments............................ dominicanus Borgmeier View in CoL
6 Microtrichia on T1+2–T6 larger and less dense (e.g. Figure 39 View Figures 38, 39 )............. 7
– These microtrichia smaller and more dense ( Figure 38 View Figures 38, 39 )................... 8
7 T8 obscure in posterior two-thirds, posterior end of S 8 in form of a stirrup-like loop (which may be pale) and spermatheca relatively large ( Figure 45 View Figures 43–45 )... heymonsi Stobbe View in CoL
– T8 more strongly developed, no loop at rear of S8 and spermatheca relatively small ( Figures 65, 66 View Figures 65, 66 )......................................... Species H
8 T8 a distinct rod, spermatheca and furca smaller and pale, S8 without loop at rear end ( Figures 63, 64 View Figures 63, 64 ). Hind tarsus with ventral hair palisade on basitarsus only.............................................................. Species G
– T8 obscure, spermatheca and furca larger and former dark, S8 with a posterior loop ( Figures 26, 27 View Figures 26, 27 ). First two segments of hind tarsus with a ventral hair palisade.......................................... depressus Meijere View in CoL
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