Hecamedini Mathis

Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2012, Revision of New World Species of the Shore-fly Subgenus Allotrichoma Becker of the Genus Allotrichoma with Description of the Subgenus Neotrichoma (Diptera, Ephydridae, Hecamedini), ZooKeys 161, pp. 1-101 : 5-16

Tribe Hecamedini Mathis

Hecamedini Mathis 1991: 2. Type genus: Hecamede Haliday 1837 [phylogeny]. Mathis and Zatwarnicki 1995: 149-160 [world catalog].

Diagnosis.

The tribe Hecamedini is distinguished from other tribes of Gymnomyzinae by the following combination of characters: Head: Arista with 3-5 dorsally branching rays, longer 2 or 3 rays subequal, inserted toward aristal base; compound eye bare of microsetulae or the latter very sparse. Thorax: Usually with a gray to silvery stripe on thorax from postpronotum through ventral portion of notopleuron; anterior supra- alar seta lacking; posterior notopleural seta inserted at distinctly elevated position, especially as compared to anterior seta; anepisternum usually two toned, dorsal portion concolorous with mesonotum, ventral portion gray; anepisternum with 2 subequal setae inserted along posterior margin. Wing: venation of wing generally pale colored; vein R2+3 elongate, section III much shorter than section II; apical section of vein M longer than section between crossveins r-m and dm-cu; alula wide, width subequal to that of costal cell. Abdomen: Male terminalia: Pregonite either lacking or fused indistinguishably with postgonite; subepandrial sclerite lacking; postgonite generally elongate and bearing few setulae, usually only 2 are conspicuous.

Phylogenetic considerations.

Mathis (1991) placed Allotrichoma in the tribe Hecamedini Mathis (subfamily Gymnomyzinae ), and in his proposed phylogeny for genera within Hecamedini , Allotrichoma and related genera comprised the most derived lineages within the tribe. In this study, we have re-examined the evidence, all morphological characters, in an attempt to discover more definitively the phylogenetic placement of Allotrichoma and related taxa, especially those taxa that have been treated as subgenera within Allotrichoma . The basic question is "What are the phylogenetic relationships (hypothetical) among taxa closely related to or within Allotrichoma ?" As background, we first present a summary of the evidence and relationships at the tribal level (within Gymnomyzinae ) and then proceed to the evidence and our analysis of it for taxa within Hecamedini .

The tribe Hecamedini , which is one of six tribes now placed in the subfamily Gymnomyzinae ( Mathis and Zatwarnicki 1995), appears to be most closely related to the tribe Lipochaetini ( Zatwarnicki 1992, Mathis and Zatwarnicki 2004). Hecamedini 's sister-group relationship with Lipochaetini is corroborated by two synapomorphies ( Zatwarnicki’s (1992) characters 59 and 60): 1. Pre- and postgonites fused and/or reduced; 2. Posterior notopleural seta inserted dorsad of level of anterior seta (thoracic character 7(28) below).

Hecamedini are distinguished from Lipochaetini , and the tribe’s monophyly is confirmed by the following characters (synapomorphies are noted by an *): *1. Arista bearing 3-5 dorsally branching rays, longer 2-3 rays subequal, inserted toward aristal base (character 7(9) below); *2. Compound eye bare of microsetulae or the latter very sparse (character 8(10) below); *3. Usually with a gray to silvery stripe on thorax from postpronotum through ventral portion of notopleuron (character 6(27) below); *4. Anterior presutural supra-alar seta lacking (character 3(24) below); *5. Posterior notopleural seta inserted at distinctly elevated position, especially as compared to anterior seta (character 8(29) below); 6. Venation of wing generally pale colored; 7. Gonite present, triangular to narrowly triangular (character 13(49) below), and bearing few setulae, usually only 2 are conspicuous ( Discocerinini , Hecamedini ; lacking in Lipochaetini ) (character 14 (50) below).

With the phylogenetic background for further study of the tribe Hecamedini within the subfamily Gymnomyzinae established and the monophyly of Hecamedini documented, we now proceed with the cladistic analysis and resultant relationships among the included genera, but with a few explanatory remarks first. In the presentation on genus-level relationships that follows, the characters used in the analysis are listed first. Each character is immediately followed by a discussion to explain its states and to provide perspective and any qualifying comments about that character. After presentation of the information on character evidence, an hypothesis of the cladistic relationships is presented and briefly discussed. A detailed, species-level phylogeny is beyond the scope of this paper, especially as Allotrichoma sensu stricto is essentially found worldwide except for the Neotropical Region, and herein we focus primarily on the New World fauna. Our intent here is to present evidence and an analysis of that evidence in an attempt to determine intermediate clusters of taxa, such as subgenera and species groups within Allotrichoma . We have allocated all taxa within Allotrichoma to one of three subgenera ( Allotrichoma , Neotrichoma , Pseudohecamede ), and within the subgenus Allotrichoma , four species groups (alium, dyna, laterale, and simplex species groups). The New World species of the subgenus Allotrichoma are in two of the species groups: laterale ( Allotrichoma bezzii , Allotrichoma deonieri , Allotrichoma dynatum , Allotrichoma lacteum , Allotrichoma lasiocercum , Allotrichoma occidentale , Allotrichoma robustum , Allotrichoma sabroskyi , and Allotrichoma schumanni ) and simplex ( Allotrichoma bifurcatum , Allotrichoma simplex , and Allotrichoma wallowa ). The cladogram (Fig. 2) is the primary mode to convey relationships, and the discussion is to supplement the cladogram and is intended only to complement the latter. In the discussion of character data, a “0” indicates the state of the outgroup; a “1” or “2” indicates the derived states. Multistate characters (1, 2, 3, 4, 6, 9, 11, 12, 15, 17, 18, 25, 31, 33, 34, 40, 43, 44, 45, 46, 47, 49, 50, 51), which comprise 46 percent of the total number, were treated as nonadditive (-), and characters. The numbers used for characters in the presentation are the same as those on the cladogram, and the sequence is the same as noted in the charac ter matrix (Table 1). For polarization of character states within Hecamedini , we used the tribes Lipochaetini ( Glenanthe Haliday and Lipochaeta ) and Discocerinini ( Discocerina obscurella ) as the successive outgroups in this phylogenetic analysis. Runyan and Deonier (1979) cited six morphological characters from immature stages in their preliminary phylogenetic analysis. While these may have phylogenetic significance, we know so little about these characters for the taxa being treated that we are hesitant to use them. The majority of taxa would be represented by a question mark in the matrix, as we known virtually nothing about their distribution among related taxa. Hopefully this revision will promote further research on immature stages, including field work, and allow us to incorporate these kinds of characters into an analysis.

Characters Used in the Analysis. (running count in parenthesis)

GENERAL

1 (1) Vestiture in general (nonadditive): (0) partially to mostly microtomentose ( Glenanthe , Lipochaeta , Hecamede albicans , Hecamede nuda , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre , Elephantinosoma , Eremotrichoma , Neotrichoma , Allotrichoma sensu stricto); (1) mostly bare, shiny ( Discocerina ); (2) Diphuia (secondarily bare).

2 (2) Coloration in general (nonadditive): (0) gray to tan ( Glenanthe , Lipochaeta , Hecamede albicans , Hecamede nuda , Elephantinosoma , Eremotrichoma , Allotrichoma sensu lato (including Neotrichoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre )); (1) mostly black ( Discocerina ); (2) Diphuia (secondarily mostly black).

HEAD

1 (3) Size of pseudopostocellar setae (nonadditive): (0) normally developed (length about equal to distance between a posterior ocellus and anterior ocellus) ( Glenanthe , Elephantinosoma , Allotrichoma (Pseudohecamede) abdominale , Hecamede albicans , Neotrichoma ); (1) greatly reduced (length subequal to diameter of posterior ocellus) or absent ( Lipochaeta , Hecamede nuda , Allotrichoma (Pseudohecamede) salubre ); (2) well developed, proclinate ( Discocerina , Diphuia , Eremotrichoma , Allotrichoma sensu stricto).

2 (4) Position of ocellar setae (nonadditive): (0) inserted posterior to transverse alignment of anterior ocellus (most Gymnomyzinae ( Gastropini , Gymnomyzini , Lipochaetini , Ochtherini )); (1) inserted anterior to transverse alignment of anterior ocellus ( Glenanthe , Hecamedini , Discocerina ); (2) not distinguished from setulae, greatly reduced or lacking ( Lipochaeta ).

3 (5) Alignment of fronto-orbital setae: (0) aligned posterior to ocellar setae (most Ephydridae except for Hecamedini and Atissini ); (1) aligned transversely with ocellar setae ( Lipochaetini , Hecamedini , Discocerina , also in Atissini of the subfamily Hydrelliinae ).

4 (6) Relative size of fronto-orbital setae (nonadditive): (0) reclinate seta larger than proclinate seta; (1) reclinate and proclinate subequal ( Discocerina , Glenanthe , Hecamede albicans , Diphuia , Eremotrichoma , Allotrichoma sensu stricto, Allotrichoma (Pseudohecamede) abdominale , Neotrichoma ); (2) only reclinate seta well developed ( Elephantinosoma , Allotrichoma (Pseudohecamede) salubre ); (3) not distinguished from setulae, greatly reduced or lacking ( Lipochaeta , Hecamede nuda ).

5 (7) Setulae on frons: (0) lacking setulae ( Discocerina , Diphuia , Elephantinosoma , Eremotrichoma , Allotrichoma sensu lato, Hecamede nuda ); (1) bearing numerous setulae ( Glenanthe , Lipochaeta , Hecamede albicans ).

6 (8) Interfrontal setae (an interfrontal seta in addition to ocellar setae, which are usually inserted more anteriorly, usually just anterior of anterior ocellus in Hecamedini ): (0) lacking ( Discocerina , Glenanthe , Lipochaeta , Diphuia , Elephantinosoma , Eremotrichoma , Allotrichoma sensu lato , Hecamede nuda ); (1) present ( Hecamede albicans ).

7 (9) Aristal setae (nonadditive): (0) bearing 5-10 dorsally branching rays more or less evenly along arista ( Discocerina ); (1) bearing 3-5 dorsally branching rays, longer 2-3 rays subequal, inserted toward aristal base (a synapomorphy for the tribes Gymnomyzini , Hecamedini ); (2) a brush, with short setulae both dorsally and ventrally ( Lipochaetini ).

8 (10) Microsetulae on compound eye: (0) bearing microsetulae ( Discocerina , Lipochaetini , and also Hydrelliinae , probably through convergence); (1) lacking microsetulae or these very sparse ( Gymnomyzinae except for Lipochaetini ).

9 (11) Facial conformation (nonadditive): (0) distinctly but shallowly convex (Lipochaeta); (1) shallowly conically produced ( Diphuia , Allotrichoma sensu stricto, Neotrichoma ); (2) conically protrudent and carinate dorsally ( Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (3) distinctly conically produced, “tuberculate” ( Hecamede albicans , Hecamede nuda ); (4) shallowly carinate dorsally ( Discocerina , Glenanthe , Elephantinosoma , Eremotrichoma ).

10 (12) Facial coloration (nonadditive): (0) uniformly colored ( Discocerina , Glenanthe , Lipochaeta , Hecamede albicans , Hecamede nuda ); (1) darker between antennae, lighter, usually gray to whitish gray ventrally ( Elephantinosoma , Eremotrichoma , Neotrichoma ); (2) females two toned, dark dorsally (brown to golden brown), light colored ventrally; males generally uniformly dark colored ( Allotrichoma sensu lato); (3) patterned, black with vertical, silvery white microtomentose stripes and dots ( Diphuia ).

11 (13) Facial coloration: (0) not sexually dimorphic ( Discocerina , Glenanthe , Lipochaeta , Hecamede albicans , Hecamede nuda , Elephantinosoma , Eremotrichoma , Neotrichoma , Diphuia ); (1) sexually dimorphic females two toned, dark dorsally (brown to golden brown), light colored ventrally; males are generally uniformly dark colored ( Allotrichoma sensu stricto, Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ).

12 (14) Facial vestiture: (0) generally microtomentose ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma , Eremotrichoma , Hecamede albicans , Hecamede nuda , Allotrichoma sensu lato); (1) generally bare except for silvery white microtomentose stripes and dots ( Diphuia ).

13 (15) Genal seta (nonadditive): (0) present, distinct from other setulae if the latter are present ( Discocerina , Glenanthe , Elephantinosoma , Diphuia , Eremotrichoma , Allotrichoma sensu lato); (1) absent ( Lipochaeta , Hecamede nuda ); (2) several setulae but not distinct seta ( Hecamede albicans ).

14 (16) Genal height (eye-to-cheek ratio): (0) 0.27 and less ( Discocerina , Glenanthe , Diphuia , Eremotrichoma , Allotrichoma sensu lato); (1) 0.34 and greater ( Lipochaeta , Elephantinosoma , Hecamede ).

15 (17) Width of oral margin (nonadditive): (0) moderately wide ( Lipochaeta , Eremotrichoma , Hecamede nuda ); (1) narrow ( Discocerina , Glenanthe , Diphuia , Allotrichoma sensu lato, Hecamede albicans ); (2) wide ( Elephantinosoma ).

16 (18) Shape of ventral margin of face (nonadditive): (0) flat or nearly so ( Elephantinosoma ); (1) shallowly emarginate ( Discocerina , Glenanthe , Lipochaeta , Eremotrichoma , Diphuia , Allotrichoma sensu stricto, Hecamede nuda , Neotrichoma ); (2) distinctly emarginate anteriorly, concave with clypeus exposed in emargination. ( Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre , Hecamede albicans )

17 (19) Palpal color: (0) dark colored, brown to blackish brown ( Lipochaeta , Elephantinosoma , Diphuia , Allotrichoma sensu lato); (1) pale, yellowish to whitish ( Discocerina , Glenanthe , Eremotrichoma , Hecamede albicans , Hecamede nuda ).

18 (20) Shape of mouthparts: (0) normally developed, mediproboscis not especially elongate ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma , Hecamede albicans , Hecamede nuda , Eremotrichoma , Diphuia , Allotrichoma sensu stricto, Neotrichoma ); (1) geniculate, with elongate mediproboscis ( Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ).

19 (21) Clypeal vestiture: (0) microtomentose, usually gray ( Discocerina , Lipochaeta , Hecamede albicans , Allotrichoma (P.) abdominale , Allotrichoma (Pseudohecamede) salubre , Allotrichoma sensu stricto); (1) thinly microtomentose or bare, appearing black ( Glenanthe , Elephantinosoma , Eremotrichoma , Hecamede nuda , Diphuia , Neotrichoma ).

THORAX

1 (22) Number of rows of acrostichal setae, especially on posterior half: (0) 3-4 rows ( Discocerina , Glenanthe , Lipochaeta (greatly reduced and difficult to discern), Hecamede nuda , Diphuia ); (1) 2 rows ( Hecamede albicans , Eremotrichoma , Elephantinosoma , Allotrichoma sensu lato). There is a tendency for less rows of setulae on the anterior half of the scutum. We numbered rows on one side and from the posterior half of the scutum.

2 (23) Prescutellar acrostichal setae: (0) present ( Discocerina , Glenanthe , Diphuia , Elephantinosoma , Allotrichoma sensu lato); (1) greatly reduced or absent ( Lipochaeta , Hecamede albicans , Hecamede nuda , Eremotrichoma ).

3 (24) Presutural supra-alar seta (additive): (0) present ( Discocerina , Glenanthe ); (1) greatly reduced or absent ( Lipochaeta , Elephantinosoma , Hecamede albicans , Hecamede nuda , Allotrichoma (Pseudohecamede) abdominale , Eremotrichoma , Elephantinosoma , Neotrichoma , Allotrichoma (Pseudohecamede) salubre ); (2) secondarily reversed ( Diphuia , Allotrichoma sensu stricto). In Hecamede albicans , this seta is only slightly larger than surrounding setae.

4 (25) Number of lateral scutellar setae (nonadditive): (0) 2 pairs ( Discocerina , Glenanthe , Elephantinosoma , Diphuia , Eremotrichoma , Elephantinosoma , Allotrichoma sensu lato); (1) 3 pairs ( Hecamede albicans , Hecamede nuda ); (2) not distinguished from setulae, greatly reduced or lacking ( Lipochaeta ).

5 (26) Number of setulae on scutellar disc: (0) 0 to a few scattered setulae, less than 15 ( Discocerina , Glenanthe , Elephantinosoma , Hecamede nuda , Diphuia , Eremotrichoma , Elephantinosoma , Allotrichoma sensu lato); (1) numerous setulae, more than 20, evenly scattered ( Lipochaeta , Hecamede albicans ).

6 (27) Pleural stripes: (0) lacking stripes ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma , Diphuia , Hecamede albicans , Hecamede nuda , Elephantinosoma ); (1) with a stripe ( Eremotrichoma , Allotrichoma sensu lato).

7 (28) Anterior notopleural seta: (0) present, subequal to posterior seta ( Discocerina , Glenanthe , Lipochaeta , Hecamede albicans , Diphuia , Eremotrichoma , Elephantinosoma , Allotrichoma sensu lato); (1) greatly reduced or absent ( Hecamede nuda ).

8 (29) Position of posterior notopleural seta: (0) inserted at same level as anterior seta ( Discocerina ); (1) inserted a more dorsal position from level of anterior seta ( Hecamedini , Lipochaetini , and also many Atissini in the subfamily Hydrelliinae , probably by convergence).

9 (30) Anepisternal setulae: (0) reduced (less than 10) and/or lacking ( Hecamede nuda , Diphuia , Eremotrichoma , Elephantinosoma , Neotrichoma , Allotrichoma sensu lato); (1) numerous present, especially on dorsal 1/3 ( Discocerina , Glenanthe , Lipochaeta , Hecamede albicans ). The usual condition is for none to a few setulae in addition to the two setae along the posterior margin. If present, the setulae are usually toward the center on the dorsal half.

10 (31) Katepisternal seta (nonadditive): (0) present, well developed ( Discocerina , Glenanthe , Lipochaeta , Hecamede albicans , Diphuia , Eremotrichoma , Allotrichoma sensu lato); (1) absent ( Elephantinosoma ); (2) absent ( Hecamede nuda ).

11 (32) Color of wing membrane: (0) hyaline ( Discocerina , Glenanthe , Diphuia , Neotrichoma , Allotrichoma sensu stricto); (1) lacteous ( Lipochaeta , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre , Hecamede albicans , Hecamede nuda , Eremotrichoma , Elephantinosoma ).

12 (33) Tibial coloration (nonadditive): (0) tibiae mostly to entirely dark, similar to femora ( Discocerina , Glenanthe , Lipochaeta , Diphuia , Allotrichoma sensu lato); (1) mostly yellow, similar to basal tarsomeres, at most with thin investment of mostly white microtomentum ( Hecamede albicans , Eremotrichoma , Elephantinosoma ); (2) foretibia especially mostly grayish, only apices of foretibia mostly yellow ( Hecamede nuda ).

13 (34) Adornment of posteroventral surface of forefemur (nonadditive): (0) bearing 5-7 setae on apical 1/2-2/3 ( Discocerina , Hecamede albicans ); (1) setae lacking or with just 1-3 along this surface ( Glenanthe , Lipochaeta , Diphuia , Eremotrichoma , Elephantinosoma , Allotrichoma sensu lato); (2) setae along this surface greatly enlarged ( Hecamede nuda ).

14 (35) Tarsomere 1 of foreleg: (0) lacking black setae at base of posteroventral surface ( Discocerina , Glenanthe , Lipochaeta , Hecamede albicans , Diphuia , Eremotrichoma , Elephantinosoma , Allotrichoma sensu lato); (1) bearing 2 or 3 black setae inserted toward base of posteroventral surface ( Hecamede nuda ).

15 (36) Setae at base of tarsomere 1 of hindleg: (0) mostly yellow ( Glenanthe , Hecamede albicans , Diphuia , Eremotrichoma , Elephantinosoma , Allotrichoma sensu lato); (1) 2-4 black setae inserted near base on anteroventral surface ( Discocerina , Lipochaeta , Hecamede nuda ).

ABDOMEN

1 (37) Number of abdominal tergites normally visible in ♂: (0) 5 abdominal tergites usually exposed and visible, none wholly retracted into preceding tergite ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma ); (1) only 4 abdominal tergites generally exposed and visible, tergite 5 mostly to wholly retracted within tergite 4 ( Hecamede , Eremotrichoma , Allotrichoma sensu lato, Diphuia ).

2 (38) Relationship of tergite 5 and sternite 5 (additive): (0) tergite separate from ventral sternite ( Discocerina , Glenanthe , Lipochaeta , Hecamede , Elephantinosoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre , Neotrichoma ); (1) tergite 5 moderately narrow, forming a complete ring, especially anteriorly, with sternite ( Diphuia ); (2) tergite relatively narrow, forming a tube-like structure, sternite 5 reduced ( Eremotrichoma , Allotrichoma sensu stricto (= alium, laterale, and simplex groups)).

3 (39) Length of tergite 5 of ♂ (nonadditive): (0) tergite relatively short (length usually less than tergite 4), comparatively wide, trapezoidal and/or triangular ( Discocerina , Elephantinosoma ); (1) tergite 5 comparatively short, band-like ( Hecamede , Diphuia , Eremotrichoma , Neotrichoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (2) tergite moderately long ( Glenanthe , Lipochaeta ); (3) tergite 5 comparatively long ( Allotrichoma sensu stricto).

4 (40) Presence or absence of relatively large, anterior, digitiform, paired apodemes of tergite 5 of ♂: (0) absent ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma , Diphuia , Hecamede , Allotrichoma sensu lato; (1) present ( Allotrichoma dyna , Eremotrichoma sp. n. from Namibia (incertae sedis)).

5 (41) Condition of ventral margin of tergite 5 of ♂: (0) simple, unadorned ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma , Diphuia , Hecamede , Eremotrichoma , Neotrichoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ): (1) with a ventral tergal process (these structures are paired, i.e., one on each side, and are apparently tergal in origin; Allotrichoma sensu stricto).

6 (42) Condition of sternite 5 of ♂: (0) simple, an unadorned, flat sclerite, lacking a medial process ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma , Diphuia , Hecamede , Eremotrichoma , Neotrichoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (1) bearing a medial, unpaired structure with apical setulae (an autapomorphy of the Allotrichoma sensu stricto).

7 (43) Shape of cerci (nonadditive): (0) length normal, not longer than epandrium, oval ( Discocerina , Glenanthe , Lipochaeta , Hecamede , Diphuia , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre , Eremotrichoma , Neotrichoma , Allotrichoma dyna ); (1) length normal, not longer than epandrium, extensively fused laterally and ventrally with epandrium ( Elephantinosoma , Allotrichoma alium group); (2) cerci greatly elongate, curved laterally, thinly developed (an autapomorphy of the Allotrichoma simplex group of Allotrichoma sensu stricto); (3) cerci greatly elongate, robustly developed, especially apically (an autapomorphy of the Allotrichoma laterale group of Allotrichoma sensu stricto).

8 (44) Vestiture of cerci (nonadditive): (0) not bearing elongate setae at ventral margin ( Discocerina , Glenanthe , Lipochaeta , Elephantinosoma , Hecamede , Eremotrichoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre , Neotrichoma ); (1) ventral margin bearing conspicuously longer setae ( Allotrichoma alium and Allotrichoma laterale groups); (2) ventral margin bearing 2 elongate setae ( Diphuia ); (3) 2-4 short setae at ventral apex of cercus ( Allotrichoma simplex group).

9 (45) Condition of surstylus (nonadditive): (0) separate from epandrium ( Discocerina , Glenanthe , Lipochaeta , Diphuia , Hecamede ); (1) lost or fused indistinguishably with epandrium ( Elephantinosoma ); (2) secondarily separate from epandrium ( Neotrichoma sp. n. from Namibia (incertae sedis)); (3) fused to ventral margin of epandrium+cercus complex ( Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (4) fused to ventral margin of epandrium ( Eremotrichoma , Allotrichoma (laterale and simplex groups); (5) secondarily fused indistinguishably with epandrium ( Allotrichoma alium group).

10 (46) Size of surstylus (nonadditive): (0) large, distinct ( Glenanthe , Lipochaeta , Hecamede , Diphuia , Eremotrichoma ); (1) greatly reduced, rodlike ( Neotrichoma sp. n. from Nimibia (incertae sedis)); (2) greatly reduced, lobelike ( Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (3) moderately reduced, usually narrow ( Allotrichoma sensu stricto); (4) size not evident ( Discocerina , Elephantinosoma ).

11 (47) Shape of Phallapodeme (nonadditive): (0) typical, roughly quadrate to broadly triangular ( Discocerina , Glenanthe , Lipochaeta , Hecamede , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre , Diphuia ); (1) narrowly triangular ( Elephantinosoma ); (2) triangular with concave sides, producing narrow, digitiform-like extensions ( Allotrichoma sensu lato without Pseudohecamede ).

12 (48) Relationship of phallapodeme to base of aedeagus: (0) separate but approximate ( Glenanthe , Lipochaeta , Elephantinosoma , Hecamede , Diphuia , Allotrichoma sensu lato without Neotrichoma ); (1) phallapodeme fused to base of aedeagus ( Discocerina , Neotrichoma ).

13 (49) Shape of gonite (nonadditive): (0) broadly to moderately triangular ( Discocerina , Elephantinosoma , Hecamede , Diphuia , Eremotrichoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (1) with an anterobasal process ( Neotrichoma ); (2) narrowly rectangular to almost tubular ( Allotrichoma sensu stricto); (3) lacking a gonite ( Glenanthe , Lipochaeta ).

14 (50) Apical gonal setulae (nonadditive): (0) several setulae, especially along dorsal margin ( Hecamede , Diphuia ); (1) 2 setulae, usually 1 apical, the other apicoventral ( Allotrichoma sensu stricto); (2) 1 subapical setulae ( Elephantinosoma ); (3) 3 setulae, 2 dorsal and 1 subapical ( Eremotrichoma , Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (4) 3 setulae (2 apicodorsally, 1 subapical) or 2 setulae (both apical) ( Neotrichoma ); (5) gonite and setulae lacking ( Glenanthe , Lipochaeta ); (6) 1 apical setula ( Discocerina ).

15 (51) Shape of aedeagus (nonadditive): (0) tubular ( Glenanthe , Lipochaeta , Hecamede , Diphuia , Eremotrichoma , Allotrichoma sensu stricto, Allotrichoma (Pseudohecamede) abdominale , Allotrichoma (Pseudohecamede) salubre ); (1) narrowly elongate ( Elephantinosoma ); (2) conspicuously arched ( Neotrichoma ).

16 (52) Apical aedeagal flap: (0) lacking, simple ( Hecamedini ); (1) present ( Lipochaetini ).

17 (53) Ejaculatory apodeme: (0) lacking ( Hecamedini ); (1) present ( Lipochaetini ).

Analysis and results.

Using the implicit enumeration (ie*) option of Hennig86 and TNT, which is an exhaustive search, 29 most parsimonious trees were generated from the analysis of the 53 characters. The cladograms have a length of 135 steps and consistency and retention indices of 0.64 and 0.65 respectively. The matrix was then subjected iteratively to successive weighting (xs w, ie*, cc) to determine a character’s contribution or weight ( Carpenter 1988, Dietrich and McKamey 1995). We also used the implicit weighting option in TNT. The successive weighing stabilized at 559 steps, and with stabilization, the consistency and retention indices increased to 0.89 and 0.90, respectively. Both successive and implicit weighting schemes resulted in the same two cladograms. One of these cladograms is identical to one of the 29 original trees and is our cladogram of choice (Fig. 2), being one of the most parsimonious cladograms. The two cladograms only differ in the terminal relationships of the simplex species group, i.e., whether it forms a tritomy or whether the simplex group is the sister group to the other species groups in the subgenus Allotrichoma . The analysis of characters for this cladogram is given in Table 2 and the weights of the various characters are given in Table 3.

In summary and as indicated on the cladogram (Fig. 2), the tribe Hecamedini is a monophyletic lineage (unambiguous synapomorphies 10 and 37) that is closely related to Lipochaetini (the outgroup), and these two tribes together ( Hecamedini and Lipochaetini ) are particularly well supported (synapomorphies 7, 18, 21, 24, 29, 34, and 39). The typology of the genera within Hecamedini , including subgenera within Allotrichoma , forms a stepwise hierarchy, beginning with Diphuia as the sister group to all other genera (see Mathis and Marinoni 2010, for a review and further discussion of Diphuia ), followed by the subgenera within the genus Hecamede (see Mathis 1993 for a revision and further discussion of Hecamede ). The next lineage in the hierarchy is Elephantinosoma , an Old World genus (see Mathis and Deeming 1987, for a revision and further discussion of Elephantinosoma .), followed by Eremotrichoma , which is likewise an Old World genus. Eremotrichoma , which we continue to accord generic status following recent precedent, now includes six species ( Mathis 1986a, Canzoneri and Vienna 1989, Krivosheina 1992).

All further lineages (from Neotrichoma to the end), which are the more derived lineages, are interpreted to be the genus Allotrichoma with the names of taxa denoting subgenera and species groups. This follows the precedent of Mathis (1991) and Mathis and Zatwarnicki (1995). Neotrichoma , which is a new subgenus being proposed herein, is the first lineage within Allotrichoma and is the sister-group to the remaining subgenera and species groups. The monophyly of this Neotrichoma is well established, as is its immediate sister-group, the node giving rise to the subgenera Pseudohecamede (see Mathis 1991, for a revision and further discussion of Pseudohecamede ) and Allotrichoma . Likewise, note that Pseudohecamede and Allotrichoma are well established and well documented subgenera.

In parenthetic notation, the relationships on the cladogram are as follows: ( Discocerina , (( Lipochaeta , Glenanthe ), ( Diphuia , (( Hecamede albicans , Hecamede nuda ), ( Elephantinosoma chnumi , ( Eremotichoma perspiciendum , (Neotrichoma atrilabre, ((Pseudohecamede abdominale, Pseudohecamede salubre), (Allotrichoma simplex group, (Allotrichoma laterale group, (Allotrichoma dyna group, Allotrichoma alium group))))))))))).

Key to Genera of Hecamedini Mathis