1999. The Journal of Arachnology 27:103±116

SPERMATOPHORES AND THE EVOLUTION OF FEMALE GENITALIA IN WHIP SPIDERS (, )

Peter Weygoldt: Albert-Ludwigs-UniversitaÈt, Institut fuÈr Biologie I (Zoologie), Hauptstraûe 1, D-79104 Freiburg, Germany

ABSTRACT. Whip spiders use stalked spermatophores for sperm transfer. These are complex structures, and their morphology varies among genera and families. Usually, the paired sperm masses hidden within the spermatophores are small, and there has been a co-evolution of spermatophores and those parts of the female genitalia which are used to pick up the spermatozoa and to store spermatozoa. These are structures like specialized sclerotizations, glands or, in a few species, seminal receptacles which are hidden inside the genital atrium (or uterus externus). In most species there are paired erectile bodies, homologous to genital appendages, which are attached to the dorsal side of the genital operculum which also is part of an appendage homologon. All these structures vary among genera and families. The comparison of sper- matophores and genitalia of different species belonging to most genera and families suggest that the female gonopods consist primarily of paired cushion-like structures, each equipped with a small ®nger-like ap- pendage vestige. These appendage vestiges are retained in many species, particular in the and Charontidae. They are erectile by increase in blood pressure, and they are thereby probably bent in characteristic ways and thus can pull off the sperm masses from the spermatophore. In some Charinidae, and in some species of Damon and Phrynichus (Phrynida, Phrynichidae) these appendage vestiges are totally lost. In the Phrynidae, on the other hand, they have become sclerotized and hard. They form the well-known claw-like sclerites, and an invagination at the base of each sclerite has been shaped to form a true seminal receptacle. Similar genitalia have evolved convergently in the genus Trichodamon (Phryn- ida, Phrynichidae). Spermatophores and the corresponding female genitalia and their mechanisms of a number of genera from most families are described and illustrated.

Whip spiders transfer spermatozoa by genera and families, and the same is true for means of stalked spermatophores (Alexander the female genitalia, in particular for those 1962a, b; Klingel 1963; Weygoldt 1969). Af- structures which are used to pick up the sper- ter a prolonged courtship dance which the matozoa. After sperm transfer, an empty sper- male performs in front of the female, he turns matophore is left behind or, in a few species, around until facing the same direction as the is eaten either by the male or the female. female and standing in front of her. In this The distal genitalia of a whip spider of ei- position he deposits a spermatophore and at- ther sex are composed of a large genital atri- taches its stalk to the substratum. Thereafter um, homologous to the uterus externus of spi- he turns around to face the female and lures ders, a large genital operculum, and paired her toward the spermatophore. The female erectile bodies attached to the dorsal or inner then steps over the spermatophore and picks side of the genital operculum (Weygoldt et al. 1972). These erectile bodies are considered to up the sperm. be homologous to genital appendages, to the The spermatophores are large and complex endopods of the opisthosomal appendages of structures. They consist of a stalk, a sper- eurypterids or xiphosurids (Pocock 1894; matophore head and paired sperm masses or, Werner 1935; Weygoldt 1970); they are there- in other species, sperm packages. Each indi- fore termed gonopods here. The genital oper- vidual spermatozoon is rolled up and encap- culum with its lateral book lungs is homolo- sulated, and the globular cells are either glued gous to the genital operculum of xiphosurids together or surrounded by secretion. The and eurypterids which is part of the same pair sperm masses are small when compared to the of appendages, the book lungs or, in xipho- size of the total spermatophore. Spermato- surids the book gills, representing the exo- phore morphology varies between species, pods.

103 104 THE JOURNAL OF ARACHNOLOGY

In the male, the gonopods are two-seg- taxon Amblypygi. As to the function, most of mented. They form an unpaired complex my description is inferred from the morphol- structure provided with muscles and haemo- ogy of the structures. Many whip spiders are lymph spaces and a complex central cavity unable to walk and to mate on glass; therefore, which acts as a mold for the formation of the direct observation is impossible. spermatophore head. It also contains grooves As a base for the discussion of the evolu- through which the secretions from several tion of genitalia I use the cladogram and sys- large glands can be lead to the exterior in or- tem of Weygoldt (1996a, b) (Table 1). In this der to attach the spermatophore stalk to the system, the African genus Paracharon is con- ground. Kraus (1970) suggested that the shape sidered the sister group of the remaining am- of the male genitalia could provide useful blypygids, the Euamblypygi. This group is di- characters for . The problem is that vided into two taxa, the Charinidae and the the shape of these organs depend heavily on Neoamblypygi. The Charinidae is mainly the state of preservation. Genitalia of two characterized by plesiomorphies; I have not males of the same species sometimes appear found convincing synapomorphies. All char- much more different from each other than inid genera are in urgent need of revision. In those from two males of two different species. particular, it is not clear whether Charinus Si- The spermatophores formed in these male mon 1892 is a monophyletic group and genitalia are complex and diverse. Their whether Charinides Gravely 1911 should be sperm masses are located at various positions considered a junior synonym of Charinus as within the spermatophore head. Unfortunately Delle Cave (1986) assumes. The Neoambly- the spermatophores of only a limited number pygi, however, is united by several synapo- of species are known. They will be described morphies. It contains the taxa Charontidae as subsequently. restricted by Quintero (1986) and the Phryn- The female genitalia are much simpler. The ida or Apulvillata, and these are divided into genital atrium contains specialized sclerotiza- the Phrynidae and Phrynichidae, both char- tions which vary among species, glandular acterized and united by convincing synapo- structures and various structures used for morphies. sperm storage. Even true seminal receptacles have evolved convergently in some groups. RESULTS The gonopods are cushion-like structures with Paracharon.ÐAccording to the taxonomic or without vestiges of the appendage telopod- analysis, Paracharon caecus Hansen 1921 is ids. These telopodids, here termed appendage the most plesiomorphic species and the adel- vestiges, are used to pick up the sperm mass photaxon of all remaining Amblypygi, the from the spermatophores. Their morphology Euamblypygi. Its female gonopods are simple varies considerably between species, genera soft cushions (Fig. 1). Spermatphores are not and families. Just as with male copulatory or- known, therefore the function of the gonopods gans, there has been a co-evolution of sper- are unclear; and it is also unclear whether the matophores and female genitalia. simple gonopods are plesiomorphic or the re- All whip spiders will mate several times if sult of simpli®cation. they have the chance. The females become Charinidae and Charontidae.ÐGonopods unreceptive once oogenesis has reached a cer- with a soft, ®nger-like appendage vestige (Fig. tain stage. All whip spiders are long-lived and 2, 3) are found in many charinid and charontid continue to molt and to grow after having whip spiders. They are probably synapo- reached sexual maturity. During molting, the morphic for the Euamblypygi or, if the geni- females loose all stored spermatozoaÐwhich talia of Paracharon are secondarily simpli- remain in the shed storage organs. The fe- ®ed, for all Amblypygi. males become receptive again soon after molt- Such ®nger-like appendage vestiges as ing. shown in Fig. 2, 3 for Charinus koepkei Wey- In the following discussion I will demon- goldt 1972c may be short and pointed as in strate different types of spermatophores and this case and in Charinides bengalensis the corresponding female genitalia and de- Gravely 1911 or much longer as in several scribe how these are used to pick up the sperm other Charinus species, e.g., Charinus afri- masses and how they have evolved within the canus Hansen 1921 (Weygoldt 1972a). The WEYGOLDTÐSPERMATOPHORES AND GENITALIA IN THE AMBLYPYGI 105 Table 1.ÐThe amblypygid genera, their relationships according to Weygoldt (1996a and 1996b), their distribution, and species numbers. The species numbers for many genera are guesses based on descriptions from the last century. Only for the Phrynidae and Phrynichidae can reliable data be given; they are based on the revisions of Mullinex (1975), Quintero (1981, 1983, a few more species have been described since then), Weygoldt (1998) and the author's unpublished data on Damon. 106 THE JOURNAL OF ARACHNOLOGY

Figures 1±7.ÐFemale genitalia and spermatophores of some charinid and charontid Amblypygi. 1. Female genitalia of Pracharon caecus; dorsal aspect; 2. Female genitalia of Charinus koepkei, dorsal aspect; 3. Same, posterior aspect (from Weygoldt 1972c); 4. Spermatophore of Sarax sarawakensis in lateral view; 5. Female genitalia of Sarax sarawakensis, dorsal aspect; 6. Spermatophore of Stygophrynus longispina; 7. Female genitalia of Stygophrynus longospina, dorsal aspect. (s ϭ sperm mass). actual appearance may vary between speci- molymph pressure and withdrawn by muscles, mens, depending on the state of preservation and that they are bent and strengthened in a or on haemolymph pressure during preserva- species speci®c way and thus can pull off the tion. For most species, spermatophores are not protruding sperm masses during sperm trans- known. It is most likely that the ®nger-like fer. appendage vestiges of the gonopods can be However, a few examples have been stud- elongated or erected by an increase in hae- ied. In Sarax sarawakensis (Thorell 1888) WEYGOLDTÐSPERMATOPHORES AND GENITALIA IN THE AMBLYPYGI 107

(Charinidae), the spermatophore head is com- erectile appendage vestige. Further, the pos- plex, with paired wing-like appendages of terior margin of the genital operculum is which the functional signi®cance is obscure. transparent and forms a hard and sharp edge They probably provide the necessary stimuli (Fig. 12). The spermatophore is unique among for the gonopods to ®nd the two protruding amblypygids (Fig. 11). There is a strong, tri- sperm masses (Fig. 4) (Weygoldt 1990). The angular stalk which ®rmly attaches the struc- inactive gonopods are rounded in this species ture to the ground, even to sand. The sper- (Fig. 5), but it is likely that they can also be matophore head consists of a ¯at plate elongated and pull off the sperm masses dur- carrying two strong sperm packages, each ing sperm transfer. The situation is similar in with a spacious sperm reservoir and an open- Stygophrynus longispina Gravely 1915 ing at its tip. This tip is bent upwards and (Neoamblypygi, Charontidae). Its spermato- forms an embolus armed with two small phore (Fig. 6) (Weygoldt 1990) also carries hooks. The reservoirs of both sperm packages two protruding sperm masses. They are join proximally; here they contain no sper- mounted on the distal ends (viewed from the matozoa but a swelling substance which, on male) of the spermatophore head. The sper- contact with aqueous solutions, presses out the matophore stalk is inserted at about the center spermatozoa stored distally. This is one mech- of the spermatophore head. Thus, when the anism. There is another, more important female presses down the proximal end of the mechanism: The ¯at plate carrying the sperm spermatophore head with her genital opercu- packages acts as a spring. If the whole struc- lum, the distal end will raise and move the ture is bent upwards distally, it arrests at about sperm masses into the female gonopore. The 45Њ, and two rod-like structures at the upper folded appearance of the female genitalia and part of the spermatophore stalk act as pistons its appendage vestiges (Fig. 7) suggest that pressing out the sperm masses. During sperm these can be in¯ated considerably and can tear transfer, the female attaches the sharp edge of off the sperm packages during sperm transfer. the margin of her genital operculum under the Charinus is a large genus distributed cir- hooks of the emboli and then bends the sperm cumtropically over all continents and also oc- package upwards. The spermatozoa are there- curring on islands, even volcanic ones like by emptied into the genital atrium and stored Galapagos. Some species have evolved differ- between the roof of the atrium and a dorsal ent spermatophores, different genitalia and fold. different means of sperm transfer. In the Bra- Phrynida.ÐThe situation in the Phrynida zilian species C. brasilianus Weygoldt 1972 or Apulvillata is much clearer. This taxon con- and C. montanus Weygoldt 1972, the append- tains two families, the Phrynidae and the age vestiges of the genitalia are enlarged and Phrynichidae. thickened and have the appearance of sucker- Phrynidae.ÐIn the Neotropical Phrynidae, like or prehensile structures (Weygoldt 1972a, the female gonopods are equipped each with b) (Fig. 10). They can be extended by increase a claw-like, hard and dark sclerite (Fig. 13). in haemolymph pressure and retracted by These sclerites have long been known and strong muscles. The spermatophores are also termed cocoon-holders by BoÈrner (Werner different. They are quite simple (Figs. 8, 9), 1935). They have, however, nothing to do and the spermatozoa do not form compact, with the transportation of the egg sac. The protruding sperm masses but ¯at layers at the sclerites can be elevated by increase in hae- base of the spermatophore head (Weygoldt molymph pressure. They are further equipped 1972b, 1974a). The female picks up the sper- with a strong adductor muscle which, by su- matozoa by means of her sucker-like genitalia. per®cial view, seems to be attached to a deep They are then stored in two distal cavities of apodeme. However, at the base of each sclerite the genital atrium directly behind the ends of there is an invagination leading into a spa- the genitalia. cious seminal receptacle (Fig. 14). The aper- The situation is even more different in tures of these receptacles are covered by the Charinus seychellarum Kraepelin 1898. The sclerite bases, and the adductor muscles are genitalia are reduced to ¯at cushions in front attached to the walls of the receptacles (Fig. of which the ¯oor of the genital atrium and 15). Contraction of these muscles, thus, leads its roof are strongly sclerotized. There is no to the adduction of the sclerites and at the 108 THE JOURNAL OF ARACHNOLOGY

Figures 8±12.ÐSpermatophores and female genitalia of two species of Charinus. 8. Spermatophore of C. brasilianus, anterior view; 9. Same, lateral aspect; 10. Female genitalia of C. brasilianus, dorsal aspect (from Weygoldt 1972b); 11. Spermatophore of C. seychellarum, lateral view; 12. Female genitalia of C. seychellaraum, dorsal aspect. Abbreviations: e ϭ embolus, h ϭ hooks, rd ϭ rod-like structure which compresses the sperm package when the tip is lifted upwards. Abbreviations: s ϭ sperm mass, sp ϭ sperm package). same time widens the seminal receptacles. deeply among the sculpturing (Figs. 17, 18, The walls of the receptacles are punctured by 19, 21), and two arm-like distal extensions act many glandular pores. Nutrients or other sub- as conductors leading towards the sperm- stances are probably released through these packages. The female pulls out these sperm- pores and nourish or otherwise maintain the packages by means of her claw-like sclerites, spermatozoa (Weygoldt et al. 1972). and the sperm is thereby sucked into the sem- The males of the Phrynidae produce large inal receptacles. In Phrynus marginemacula- spermatophores with triangular, heavily sculp- tus C.L. Koch 1841, the sperm packages are tured spermatophore heads (Weygoldt 1969, attached to small plates, and these plates are 1972b, 1974b, 1977) (Figs. 16, 17, 19, 20). visible pressed underneath the claw-like scler- The formation of these complex spermato- ites after sperm transfer. phores takes quite long, 10±20 minutes. After The sculpturing varies among species and spermatophore formation, the male turns to- also the shapes of the arm-like appendages; ward the female again and touches for another and they may even be forked or T-shaped. The 10 minutes the spermatophore with his pedi- functional signi®cance of these differences is palps and chelicerae. The meaning of this be- obscure, in particular since the female geni- havior is still obscure. The attachments of a talia are quite uniform. We may assume that pheromone may be one possibility, the depo- the different sculpturings aid the female in sition of an enzyme to soften the sperm pack- recognizing the spermatophore and ®nding the ages another. The spermatophore contains two sperm packages. Another point may be that comparatively small sperm-packages hidden the sculpturing creates a large, hard, elastic WEYGOLDTÐSPERMATOPHORES AND GENITALIA IN THE AMBLYPYGI 109

variation in all four genera and in all species (Mullinex 1975; Quintero 1981; Weygoldt 1972b, 1974b, 1977). Phrynichidae.ÐThe Phrynichidae are much more variable as far as their spermato- phores and genitalia are concerned. Phrynichodamon scullyi (Purcell 1911) is a primitive species and the sister taxon of all other Phrynichidae (Weygoldt 1996a) (with the exception of Xerophrynus Weygoldt 1996, which is tentatively considered a basal offshot of the Phrynichidae, Table 1). Spermatophores and genitalia of this species resemble the sit- uation found in charinid and charontid whip spiders. In the small and simple spermato- phores, the spermatozoa form large, protrud- ing sperm masses (Weygoldt 1998a). The fe- male gonopods are equipped with soft, ®nger-like appendage vestiges which can probably be extended by haemolymph pres- sure and tear off the sperm masses. These are then stored underneath the appendage vestiges (Weygoldt 1996a) (Fig. 23). It is easy to conceive that a remote ancestor of the Phrynidae had a similar system and that the appendage vestiges became sclerotized and hard and the place at the base of these vestiges invaginated to better store the sper- matozoa. The remaining phrynichids, however, evolved into another direction. In Damon, and convergently in most Phrynichinae, the ap- pendage vestiges were lost. Figures 13±15.ÐFemale genitalia of Phrynus Some of the western species of Damon still marginemaculatus; 13. Dorsal aspect of genitalia of have appendage rudiments. In Damon john- an exuvia with the claw-like sclerites; 14. Longi- tudinal section through one of the gonopods with stonii (Pocock 1894) (Fig. 24) and in Damon the entrance to the seminal receptacle (arrow); 15. tibialis (Simon 1876) there is a small append- Cross section through one of the gonopods with the age rudiment which has, perhaps, a sensory seminal receptacle containing spermatopzoa. Ab- function; nothing is known about spermato- breviations: m ϭ muscle, rs ϭ seminal receptacle phores and sperm transfer in these species. (from Weygoldt et al. 1972). Another undescribed species from Came- roon has evolved very different genitalia. The gonopods are enlarged hook-like structures spermatophore head with a minimum of ma- which are strongly sclerotized and black (Fig. terial. Even the stalk is created with a mini- 25). Again, nothing is known about spermato- mum of material; it is not solid as may seem phores and sperm transfer, but these genitalia from Figs. 16 and 20 but its cross section is strongly suggest that the spermatophores are V-shaped instead. very different from those of other Damon spe- This unique system featuring spermato- cies. This species may be the sister taxon of phores with complexly sculptured spermato- the Phrynidae, in which case the Phrynichidae phore heads and female gonopods equipped form a paraphyletic group. But this is unlike- with claw-like sclerites and seminal recepta- ly. The Damon species are united by clear cles is one of the autapomorphies of the synapomorphies, and the genitalia of this Da- Phrynidae. The features are found with little mon species and of the Phrynidae are only 110 THE JOURNAL OF ARACHNOLOGY

Figures 16±21.ÐSpermatophores of two species of the Phrynidae. 16. Spermatophore of Heterophrynus longicornis, lateral view; 17. Anterior view of spermatophore head; 18. Right sperm package enlarged (from Weygoldt 1972b); 19. Spermatophore of Phrynus marginemaculatus, anterior view; 20. The same, lateral view; 21. One of the sperm packages enlarged (from Weygoldt 1969). Abbreviations: a ϭ arm-like distal extension, s ϭ spermatozoa, sp ϭ sperm package.

super®cially similar. There is no claw-like These cushions are used to detach large sclerite on a soft cushion-like gonopod with sperm-packages from the spermatophore seminal receptacles, but the tip of the gonopod (Weygoldt 1998a; Weygoldt & Hoffmann is sclerotized. It is more likely that this simi- 1995) (Figs. 26±28). The sperm packages are larity is the result of convergent evolution. so large that they ®ll out nearly the complete Damon medius (Herbst 1797), another West genital atrium. This is a specialty of this Da- African species, has its lost gonopodial ap- mon variegatus species group or of all Damon pendage vestiges. The gonopods are large species; the reproductive biology of the west- cushions with a deep dorsal depression. They ern species is unknown. The larger parts of look more like a depression surrounded by these sperm packages consist of a secreted large walls which join in the midline. mass which serves perhaps as a matrix to hold In all East African species of Damon, the and retain the spermatozoa within the female female genitalia are ¯at cushions without any genital atrium; seminal receptacles are miss- appendage vestiges. They are supported by an ing (Weygoldt & Hoffmann 1995). anterior sclerotized plate or bar (Fig. 29). The female genitalia of the Old World WEYGOLDTÐSPERMATOPHORES AND GENITALIA IN THE AMBLYPYGI 111

Figures 22±29.ÐSpermatophores of Phrynichodamon and Damon. 22. Spermatophore of Phrynicho- damon scullyi, lateral view (from Weygoldt 1998a); 23. Female genitalia of Phrynichodamon scullyi, dorsal aspect (from Weygoldt 1996a); 24. Female genitalia of Damon johnstonii, dorsal aspect; 25. Female genitalia of undescribed Damon species, dorsal aspect; 26. Spermatophore of Damon diadema, anterior view; 27. Anterior view of spermatophore head of emptied spermatophore; 28. One of the sperm packages; 29. Female genitalia of Damon diadema, dorsal aspect (from Weygoldt & Hoffmann 1995).

Phrynichinae, the genera Phrynichus and Eu- heads consist of an outer frame and two inner phrynichus, are simple cushion-like elevations bars, each carrying a compact sperm mass at which, in some species, have partly sclero- its proximal end (Figs. 30, 31, 34, 35). At the tized walls or tooth-like sclerotized tips (Fig. distal end of the spermatophore head there are 33). There are no seminal receptacles; the arms or levers and, at the basis of these, cush- spermatozoa are stored inside the genital atri- ions. If these levers or the cushions are um. The spermatophores of all Phrynichinae pressed down, the bars carrying the sperm are complex and unique. Their spermatophore masses are elevated (Weygoldt 1998a; Wey- 112 THE JOURNAL OF ARACHNOLOGY

Figures 30±35.ÐSpermatophores of Phrynichus and Euphrynichus. 30. Lateral view of total spermato- phore of Phrynichus ceylonicus, 31. Dorsal aspect of spermatophore head of same; 32. Spermatophore head of emptied spermatophore (from Weygoldt & Hoffmann 1995); 33. Female genitalia of Phrynichus ceylonicus, dorsal aspect (from Weygoldt 1998b); 34. Lateral view of total spermatophore of Euphrynichus bacillifer; 35. Dorsal aspect of spermatophore head (from Weygoldt 1998a). Abbreviations: b ϭ bar carrying sperm mass, c ϭ cushion, h ϭ lateral horn, s ϭ sperm mass. goldt & Hoffmann 1995) (Fig. 32) and the genus, has female genitalia which bear some sperm masses can be grasped by the female similarity to those of the Phrynidae (Weygoldt gonopore. 1977). The gonopods are soft cushions with a Trichodamon froesi Mello LeitaÄo 1940, a hook-like appendage vestige, and close to member of the only New World phrynichid each hook there is s small seminal receptacle WEYGOLDTÐSPERMATOPHORES AND GENITALIA IN THE AMBLYPYGI 113

Figures 36±40.ÐSpermatophore and female genitalia of Trichodamon froesi (from Weygoldt 1977). 36. Lateral view of total spermatophore; 37. Dorsal aspect of spermatophore head; 38. Lateral view of emptied spermatophore head; 39. Female genitalia, dorsal aspect; 40. Longitudinal section through one of the gonopods. Abbreviations: b ϭ bar carrying sperm mass, c ϭ cushion, h ϭ lateral horn, ho ϭ hook-like structure, rs ϭ seminal receptacle, s ϭ sperm mass.

(Figs. 39, 40). The spermatophore of this spe- spectacular variations, it will not discussed cies is composed of the same parts as those here in detail. One of the characteristic fea- of the Old World Phrynichinae and have the tures of the Amblypygi is the fact that the same mechanism, but they are stronger, with male turns away from the female during sper- a short and stout stalk and a strong outer matophore formation. The Amblypygi share frame (Figs. 36±38). If the large cushions are this behavior with the Uropygi; in other arach- pressed down, the bars carrying the sperm nids which deposit spermatophores, the male masses are lifted and ®nally arrested (Fig. 38). faces the female during spermatophore pro- The hook-like appendage vestiges are proba- duction. This characteristic behavior can be bly used to grasp around the bases of the assumed to be synapomorphic either for the sperm masses and lead them into the seminal Pedipalpi (Uropygi and Amblypygi) or for the receptacles. Megoperculata (Uropygi, Amblypygi and Ar- aneae). I believe, and Alexander & Ewer DISCUSSION (1957) do also, that this latter possibility is the Courtship behavior is similar in all whip correct one. As a consequence, we have to spiders observed; and, although there are assume that spiders lost this behaviorÐper- 114 THE JOURNAL OF ARACHNOLOGY haps better, changed this behaviorÐin the The genitalia also provide useful characters course of the evolution of their characteristic for taxonomy. For example, all Phrynidae are indirect -direct method of sperm transfer. Al- characterized by gonopods with claw-like exander (1962a, b) was the ®rst to observe sclerites and seminal receptacles. Species mating in amblypygids. She described sper- without this morphological arrangement can- matophore formation as a two step process: not belong to the family Phrynidae unless it The male ®rst deposits an empty spermato- can be shown that the species in question phore, then turns to the female again and ®lls shares other synapomorphies with the Phryn- the spermatophore with spermatozoa. Alex- idae and has not yet evolved the typical gen- ander & Ewer (1957) used this two step pro- italia, or that it has reduced these structures. cess to understand the evolution of mating be- Thus, the Namibian Xerophrynus machadoi havior in spiders. In some spiders, the male (Purcell 1901) which had been described as courts the female for a while, then interrupts Paraphrynus machadoi, has female genitalia courtship in order to ®ll his palpal copulatory different from those of all phrynids and, in organs. Thereafter he turns toward the female fact, different from those of all other species. again and resumes courtship. In other species, Because of other characters, this species is the ®lling of the copulatory organs and court- probably a remote plesiomorphic member of ship are two completely separated behavior the Phrynichidae (Weygoldt 1996a). Unfortu- acts. The behavior of the male whip spider, in nately, the reproductive biology of this desert- which he turns away from the female to pro- adapted species is not known. In captivity it duce an empty spermatophore, was hypothe- refuses to produce a spermatophore; perhaps sized by Alexander & Ewer (1957) to have reproductive behavior is triggered by a com- been the initial step leading to the reproduc- plex set of environmental changes. Therefore tive behavior of spiders. However, the obser- the mechanism of sperm transfer in this spe- vation of Alexander is incorrect. I have now cies has yet to be discovered. observed and videotaped the behavior of sev- Genitalia with claw-like sclerites and sem- eral species of Damon, including D. variega- inal receptacles are an autapomorphy of the tus, the same species Alexander observed. In Phrynidae. Quintero (1980) assumed that such all amblypgid species observed, the sperma- claw-like sclerites are an autapomorphy of the tozoa are ®rmly built into the spermatophore Phrynida (Phrynichidae and Phrynidae) and as soon as the male lifts his body and starts that the Phrynichidae, with the exception of to turn towards the female again. We can, of the undescribed Damon species, have reduced course, still assume that a behavior by which these sclerites. But this is unlikely. The Da- the male turns away from the female before mon species and the Phrynichinae are united spermatophore formation was the initial step by clear synapomorphies, and the genitalia of from which spider mating behavior evolved. this Damon species and of the Phrynidae are Male and female genitalia, or spermato- only super®cially similar. It is more likely that phores and female genitalia, have evolved as this similarity is the result of convergent evo- means to successfully transfer sperm and thus lution. ensure insemiation. I assume that they have There are many more open questionsÐin been shaped by sexual selection in the sense fact, there are more questions than answers. of Eberhard (1985). It is evident from these For example, the reproductive biology and the few examples of Amblypgi that the co-evo- exact systematic position of Musicodamon at- lution of spermatophores and female genitalia lanteus Fage 1939 within the Phrynichidae is has led to different structures and mecha- unknown. This species is known from only nisms. It is also evident that the structures four badly-preserved museum specimens. vary among genera and families and that they The situation is even worse in the Charin- can be used as characters in systematic re- idae. Although many species have the typical search. gonopods with a ®nger-like appendage ves- The comparative approach demonstrated tige, some lack them. The Brazilian species of here helps to understand the origin and evo- Charinus possess sucker-like gonopods, and lution of complex genitalia such as those of those of Charinus seychellarum are even more Trichodamon or of the Phrynidae with their different. The spermatophre and female geni- claw-like sclerites and seminal receptacles. talia of this species are unique among ambly- WEYGOLDTÐSPERMATOPHORES AND GENITALIA IN THE AMBLYPYGI 115 pygids. The spermatophore resembles those of of mating behavior in spiders. American Nat., some pseudoscorpions or whip scorpions 91:311±317. (Uropygi). It came as a surprise to ®nd such Delle Cave, L. 1986. Biospeleology of the Soma- different spermatophores within one genus, liland Amblypygi (Arachnida, Chelicerata) of the and it is hard to believe that species with such caves of Showli Beerdi and Mugdile (Bardera, Somaliland). Redia (Florence), 69:143±170. different genitalia should be found in the same Eberhard, W.G. 1985. Sexual selection and genus. The gonopods of Tricharinus Quintero genitalia. Harvard Univ. Press, Cambridge, Lon- 1986 are also different. Quintero (1986) pub- don. lished SEM pictures which reveal similar de- Klingel, H. 1963. Paarungsverhalten bei Pedipal- tails to my own unpublished light microscopy pen (Thelyphonus caudatus L., Holopeltidia, studies. The mechanism of these gonopods re- Uropygi, und Sarax sarawakensis Simon, Char- main unknown, as the spermatophores are not ontidae, Amblypygi). Verh. dt. zool. Ges., 1962: known; and there are no histological data. The 452±459. various spermatophores and genitalia in dif- Kraus, O. 1970. Genitalmorphologie und Syste- ferent Charinus species and their relatives matik der Amblypygi (Arachnida). Bull. Mus. Nat. Hist. Natur. 22 seÁr., 41, Suppl. no. 1, 1969: may suggest that this genus is a paraphyletic 176±180. or even polyphyletc assemblage, and the fact Mullinex, C.L. 1975. Revision of Paraphrynus that the Charinidae as a whole are not char- Moreno (Amblypygida: Phrynidae) for North acterized by synapomorphies shows that stud- America and the Antilles. Occ. Papers California ies of the reproductive biology and the asso- Acad. Sci., 116:1±80. ciated structures of these genera are urgently Pocock, R.I. 1894. Notes on the Pedipalpi of the needed and that there is ample work to do for family Tarantulidae contained in the collection of the next generation. the British Museum. Ann. Nat. Hist. Ser. 6, 14: Another unsolved question is the functional 273±258. signi®cance of various part of the complex Quintero, D. 1980. Systematics and evolution of Acanthophrynus Kraepelin (Amblypygi, Phryni- spermatophore heads. Perhaps studies with dae). Pp. 341±347. In 8th Intern. Congr. Arach- larger numbers of specimens, some of which nol., Wien. may produce spermatophores with slight mor- Quintero, D. 1981. The amblypygid genus Phrynus phological differences, may lead to an under- in the Americas (Amblypygi, Phrynidae). J. Ar- standing of female choice and sexual selec- achnol., 9:117±166. tion. Sexual selection and sperm competition Quintero, D. 1983. Revision of the amblypygid have never been studied in any whip spider, spiders of Cuba. Studies Fauna CuracËao and oth- and the meaning or information content of the er Caribbean Islands, 196:1±54. different behavior elements during courtship Quintero, D. 1986. Revision de la classi®cation de or ®ghting are completely obscure. Amblypygidos pulvinados: Creation de subor- denes, una nueva familia y un nuevo genero con ACKNOWLEDGMENTS tres nuevas especies (Arachnida, Amblypygi). th I am grateful for all those who helped to Pp. 203±212. In Proc. 9 Intern. Congr. Arach- nol., Panama 1983, Smithsonian Inst. Press. collect whip spiders in different countries; Werner, F. 1935 Scorpiones, Pedipalpi. Pp. 1±490. they have been thanked in previous papers. In Bronns Klassen und Ordnungen des Tierreich- William Eberhard, Brent Opell and an anon- es, 5. Bd, IV Abt. 8. Buch, Akad. Verlagsgesell- ymous reviewer helped to improve the man- schaft, Leipzig. uscript. My studies were sponsored by the Weygoldt, P. 1969. Beobachtungen zur Fortp¯an- Deutsche Forschungsgemeinschaft. zungsbiologie und zum Verhalten der Geiûelspinne Tarantula marginemaculata C.L. LITERATURE CITED Koch (Chelicerata, Amblypygi). Z. Morph. Ti- Alexander, A.J. 1962a. Courtship and mating in ere, 64:338±360. amblypygids (Pedipalpi, Arachnida). Proc. Zool. Weygoldt, P. 1970. Lebenszyklus und postem- Soc. London, 138:379±383. bryonale Entwicklung der Geiûelspinne Taran- Alexander, A.J. 1962b. Biology and behavior of tula marginemaculata C.L. Koch (Chelicerata, Damon variegatus Perty of South Africa and Ad- Amblypygi) in Laboratorium. Z. Morph. Tiere, metus barbadensis Pocock of Trinidad, W.I. 67:58±85. (Arachnida, Pedipalpi). Zoologica (New York), Weygoldt, P. 1972a. Charontidae (Amblypygi) aus 47:25±37. Brasilien: Beschreibung von zwei neuen Chari- Alexander, R.D. & D.W. Ewer. 1957. On the origin nus-Arten, mit Anmerkungen zur Entwicklung, 116 THE JOURNAL OF ARACHNOLOGY

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