Henicops Newport, 1844

Hollington, L. M. & Edgecombe, G. D., 2004, Two New Species of the Henicopid Centipede Henicops (Chilopoda: Lithobiomorpha) from Queensland and Victoria, With Revision of Species from Western Australia and a Synoptic Classification of Henicopidae, Records of the Australian Museum 56, pp. 1-28 : 3-4

Henicops Newport, 1844

Type species. Henicops maculatus Newport, 1844 ; by original designation.

Diagnosis. Member of Lamyctes-Henicops Group with 29– 51 antennal articles; maxillipede coxosternum subtrapezoidal, dental margin moderately wide, with 3+3 or 4+4 teeth (exceptionally up to 6+6), lacking pseudoporodont; mandibular aciculae abundant, arranged in two (inner and outer) rows; several laciniate or plumose setae amidst simple setae on coxal process of first maxilla; projections on (at least) tergites 9, 11 and 13; last distal spinose projection of tibia on leg 14; subdivision of basitarsus of legs 1–12 indicated by paired larger setae; tarsi of legs 13 and 14 divided into three or four tarsomeres; distitarsus of leg 15 divided into at least two tarsomeres; first genital sternite of male divided longitudinally into two sclerites; male and female gonopods abundantly setose, with numerous distally curved setae on male gonopod.

Assigned species. Lamyctes brevilabiatus Ribaut, 1923 ; Henicops dentatus Pocock, 1901a (= H. oligotarsus Attems, 1911 , n.syn.); H. milledgei n.sp.; H. tropicanus n.sp.

Discussion. The genus Henicops was erected by Newport (1844), with his concept of Henicops corresponding to the modern concept of the family Henicopidae . Two species of Henicops were originally named, Henicops maculatus from Tasmania and H. emarginatus Newport, 1844 , from New Zealand. The latter was subsequently transferred to Lamyctes Meinert, 1868 , and is a senior subjective synonym of the type species, L. fulvicornis Meinert, 1868 ( Eason, 1996) .

In erecting a new genus, Paralamyctes, Pocock (1901b) rediagnosed Henicops with emphasis on the division of the tarsi into tarsomeres. Henicops was again rediagnosed by Archey (1917), who included in that diagnosis the presence of plumose setae on the coxal process of the first maxilla, a character previously used to distinguish Lithobiidae from Henicopidae ( Chamberlin, 1912) . The “plumose” setae on the coxal process of the first maxilla in Henicops vary from laciniate ( Fig. 15J; Edgecombe et al., 2002: fig. 8H for H. maculatus ) to plumose, though the latter differ in detail from the complex plumose setae of lithobiids (Edgecombe & Hollington, 2002: fig. 9C,E). The present study frames the generic diagnosis around synapomorphies that identify Henicops as a monophyletic group within a clade that also includes Lamyctes (= Lamyctinus Silvestri, 1909a ; see Edgecombe & Giribet, 2003a), Lamyctopristus Attems, 1928 , Analamyctes Chamberlin, 1955 , Easonobius Edgecombe, 2003a , and apparently Pleotarsobius Attems, 1909 . The monophyly of this Lamyctes-Henicops Group is strongly supported by sequence data from multiple molecular markers (Edgecombe et al., 2002; Edgecombe & Giribet, 2003b), and notably by insertions in the 18S rRNA.

Henicops is united with the South African Lamyctopristus Attems, 1928 ( Edgecombe, 2004a: fig. 34D) by the mandibular aciculae being divided into inner and outer rows ( Figs. 5F, 10C). This two-row arrangement is associated with a larger number of aciculae (about 20) in Henicops than in allied henicopines. Previous diagnoses ( Archey, 1917, 1937; Attems, 1928) cited three joints in legs 1–13 as diagnostic of Henicops , but this is now observed to pertain to most but not all species (at least two undescribed species have only two tarsomeres on legs 1–12). A more general characterization of the Henicops tarsal condition is that subdivision of the basitarsus of legs 1–12 is indicated by paired larger setae. Where the tarsus has only two tarsomeres, a pair of strong, divergent setae is situated on the basitarsus in the same position as those larger setae immediately proximal to the most proximal tarsomere articulation in species with three tarsomeres, i.e., the tripartite arrangement on the tarsi of legs 1–12 in H. maculatus and the three species described herein occurs by subdivision of the basitarsus. Concerning the distitarsus, all species of Henicops uniquely share a division of the distitarsus of leg 15 into tarsomeres, a state not otherwise developed in the Henicopini (see Table 1 for a comparison of tarsal segmentation between species). The bipartite first genital sternite in males ( Figs. 6I, 11B, 16F) is invariant in Henicops . Elsewhere in Henicopidae , the division of this sternite into two sclerites is observed only in some members of Lamyctes , in those mostly African species split off by Verhoeff (1941) as Metalamyctes. The abundance of setae on the gonopods in both sexes is added to the generic diagnosis here, the number of setae in Henicops substantially exceeding that in most other Henicopinae , including other members of the Lamyctes-Henicops Group. This abundance could be explicitly defined in terms of the male gonopod having about 15 setae on the basal article and about 10 on the second and third.Among these are many distally curved setae ( Figs. 4E, 12C).

Additional distinction from Lamyctes is provided by the presence of tergal projections, subdivision of the tarsi, and a wider dental margin of the maxillipede coxosternum. A species that presents incongruence is the New Caledonian Lamyctes brevilabiatus Ribaut, 1923 . Sequences from nuclear ribosomal as well as mitochondrial markers, separately as well as in combination, indicate that this species is more closely related to Henicops than to Lamyctes (Edgecombe & Giribet, 2003a,b). The molecular data more precisely indicate an alliance with members of the Henicops dentatus Group as defined below. Apomorphic morphological characters shared with Henicops include the relatively large number of antennal articles (38–47), a relatively wide dental margin of the maxillipede coxosternum with 3+3 teeth and no pseudoporodont, laciniate setae on the coxal process of the first maxilla, and a bipartite first genital sternite in the male (AM KS82626, Mt Humboldt). The spines beneath the posterior pretarsal accessory claw are short, as in Henicops ( Fig. 14L), rather than long and needle-like as in Lamyctes (Edgecombe & Giribet, 2003a: figs. 34, 36). The New Caledonian species lacks, however, several characters shared by all other members of Henicops . It has transverse (rather than projected) posterior margins of TT11 and 13, the last distal spinose projection is on the tibia of leg 13 (rather than 14), and the tarsi of legs 13–15 are bipartite, with no trace of a subdivision of either tarsomere. Legs 1–12 have indistinct tarsal articulations.

The mandible differs from other members of Henicops in having relatively few (nine) aciculae in a single row ( Fig. 2B,C), rather than having about 20 aciculae in two rows. Cladistic analysis of morphological evidence resolves brevilabiatus as sister group of Henicops as diagnosed above in some minimal length cladograms, but as a member of Lamyctes in others, whereas combination of the morphological data with molecular data favours an ingroup position within Henicops (Edgecombe & Giribet, 2003b) . Based on strength of the molecular support together with the presence of several apomorphies of Henicops listed above, the species is reassigned to Henicops .