Brooding in Mecistocephalus International Journal of Myriapodology 3 (2010) 139-144 139 So a–Moscow Brooding in Mecistocephalus togensis (Geophilomorpha: Placodesmata) and the evolution of parental care in centipedes (Chilopoda) Gregory D. Edgecombe1, Lucio Bonato2 & Gonzalo Giribet3 1 Department of Palaeontology, Natural History Museum, Cromwell Road, London SW7 5BD, UK. E-mail: g.edgecombe@nhm.ac.uk 2 Dipartimento di Biologia, Università degli Studi di Padova, Via Ugo Bassi 58 B, I-35131 Padova, Italy. E-mail: lucio.bonato@unipd.it 3 Department of Organismic and Evolutionary Biology & Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA. E-mail: ggiribet@oeb.harvard.edu Abstract e only well-documented data on female brooding posture in the geophilomorph family Mecistocephali- dae come from Dicellophilus carniolensis (C.L. Koch, 1847), in which the mother coils around the eggs and hatchlings with the dorsal surface outwards. is posture is shared by Craterostigmomorpha and Scolopendromorpha but not by other Geophilomorpha (united as Adesmata), which coil with the ventral surface outwards. e change in brooding behaviour has been thought to coincide with the evolution of ventral glandular pores in Adesmata and defends the basal split of Geophilomorpha into Placodesmata (Mecistocephalidae alone) and Adesmata. However, a brood of another mecistocephalid, Mecistocephalus togensis (Cook, 1896), documented in situ in Cameroon, shows the mother to guard the hatchlings with the ventral surface outwards, in the manner of Adesmata rather than that seen in Dicellophilus. is observation suggests that the brooding posture may be more subject to convergence or evolutionary reversal than previously expected. Key words Placodesmata, parental care, Mecistocephalus, Phylactometria Introduction Brooding behaviour provides a valuable trait for centipede phylogenetics and systematics. Available data on maternal care in the orders Craterostigmomorpha, Scolopendromorpha, and Geophilomorpha have been summarised by Bonato & Minelli (2002: Ta- Koninklijke Brill NV and Pensoft, 2010 DOI: 10.1163/187525410X12578602960506 140 Gregory D. Edgecombe et al. / International Journal of Myriapodology 3 (2010) 139-144 ble 1). ese three orders comprise a monophyletic taxon named Phylactometria, the name referring to maternal care as a shared derived character of the group (Edgecombe & Giribet 2004). A common behavioural character of all members of Phylactometria is a prolonged period of maternal care in which the mother coils her body around the eggs and remains in this position, ceasing to feed for several weeks, and continuing to guard even after eclosion. is situation contrasts with the remaining two centipede orders, Scutigeromorpha and Lithobiomorpha, which lay single eggs that are usually concealed in soil and invariantly abandoned. Within the brooding clade, two alternative postures are observed. Scolopendromorpha (data for eight species summarised by Bonato & Minelli 2002; see Coscarón & de Ferrariis 1963; Shelley 2002: g. 1g; Chao 2008: g. 6; for additional taxa) and Craterostigmomorpha have mothers that coil around the eggs and hatchlings with the dorsal side facing outwards. Members of several families of Geophilomorpha have been observed to brood in an inverted position, with the ventral side outwards (nine species listed by Bonato & Minelli 2002; see also Arthur & Chipman 2005: g. 1D). is di erence had been regarded as a possible evolutionary novelty of Geophilomorpha as a whole (Dohle 1985) until data became available for the family Mecistocephalidae. Bonato & Minelli (2002) demonstrated that the mecistocephalid Dicellophilus carniolensis (C.L. Koch, 1847) guards the eggs and hatchlings with the dorsal side outwards, as in scolopendromorphs and Craterostigmus Pocock, 1902 rather than like other geophilomorphs. e distinction between the style of maternal care in Mecistocephalidae, which was interpreted as a plesiomorphic behaviour (shared with non-geophilomorphs) relative to that of other geophilomorph families, is congruent with prevailing views of centipede phylogenetics. As was recognised in the classi cation of Verhoe (1908 and 1918 in Verhoe 1902-1925), Geophilomorpha divide into Placodesmata (composed of Mecistocephalidae alone) and Adesmata, a clade uniting the remaining 14 currently-recognised families. e split between two monophyletic sister groups, Placodesmata and Adesmata, has been retrieved in morphological cladistic analyses (Foddai & Minelli 2000), as well as separate or combined analyses of multi-locus molecular data and morphology (Edgecombe et al. 1999; Edgecombe & Giribet 2002, 2004). e Placodesmata-Adesmata division corresponds to anatomical di erences between these groups, notably with regards to the absence or presence of ventral pores, the openings of the sternal glands. Ventral pores are observed in members of all families of Adesmata apart from the small tropical American family Neogeophilidae, albeit with repeated instances of apparent secondary losses within diverse families (Turcato et al. 1995). Ventral pores are, in contrast, lacking in Mecistocephalidae apart from doubtfully homologous structures in males only of most species in the genus Tygarrup Chamberlin, 1914 (see Bonato & Minelli 2002; Bonato et al. 2003: 573-574, for discussion). Given that the secretions of the sternal glands have been observed to harbour noxious chemicals, the broad correlation between presence of ventral pores and brooding with the ventral side away from the eggs and hatchlings invites a scenario in which the two traits are functionally linked in order to avoid the Brooding in Mecistocephalus 141 brood being exposed to the glandular secretions and/or to maintain the pores facing potential predators (Bonato & Minelli 2002). e maternal brooding posture documented in the single species Dicellophilus carniolensis has been assumed to be shared by all species of Placodesmata (= Mecistocephalidae) (ca. 170 known species), despite the lack of comparable data for other species. Here we add a new eld observation on maternal care in another mecistocephalid species. A mature female of Mecistocephalus togensis (Cook, 1896) and her hatchlings were found and photographed in situ in a piece of wood in Cameroon. is brood demonstrates that at least some mecistocephalids guard the hatchlings with the ventral side facing outwards, as in Adesmata. is variability between di erent mecistocephalids opens the question as to whether brooding posture may be more subject to homoplasy – to convergence or reversal – than appeared to be the case in the absence of these data. Description of brooding in Mecistocephalus togensis e brood documented here was found during eldwork in the Ototomo forest, near Ngoumou, Central Province, Cameroon, by L. Benavides, G. Giribet, G.N. Legrand, and J. Murienne. e locality is situated at 03º39.717’N 11º18.015’E, at an elevation of 731 m, and the specimens were photographed and collected on 5 June, 2009. e sample consists of a mature female of Mecistocephalus togensis, associated with 20 hatchlings, all of which were collected along with the mother and are housed in the Museum of Comparative Zoology, Harvard University (MCZ DNA105637). All hatchlings represent the same developmental stage, and their association is as typi es all broods in Scolopendromorpha and Geophilomorpha. e brood chamber was a cavity in a piece of wood in a decaying log, most of the volume of which was occupied by the centipedes (Fig. 1). When found, the adult female was coiled around the hatchlings, though not forming a simple loop (as usual in Craterostigmomorpha and Scolopendromorpha) but instead having at least part of the trunk in an S-curve (as usual in other Geophilomorpha, including the mecistocephalid Dicellophilus carniolensis), with two clear loops visible (Fig. 1a, b). e head of the mother had its dorsal side directed towards the hatchlings (Fig. 1a), and at least the posterior 20 of 49 leg-bearing trunk segments likewise had their dorsal side directed towards the hatchlings (Fig. 1b, d). e anterior part of the trunk (ca segments 5-8) is exposed in one view (Fig. 1a), and is also seen to have its dorsal side directed inwards, as is a section of several segments that apparently lies a short distance anterior to the rearmost 20. Given the total length of the trunk and the con ned space of the brood chamber, it appears unlikely that the concealed parts of the trunk could be twisted into a di erent dorsoventral orientation. e temporal series of photographs, recorded over a span of 30 sec, shows that the mother maintained most of the body in the same stance rather than exhibiting much mobility (Fig. 1). It is thus highly unlikely that the orientation with the dorsal side directed inwards is anything other than the posture that the mother maintained while brooding. 142 Gregory D. Edgecombe et al. / International Journal of Myriapodology 3 (2010) 139-144 Figure 1. Brooding female of Mecistocephalus togensis with 20 hatchlings in a hollow cavity inside a piece of decaying wood (Ototomo forest, Cameroon, 5 June 2009) taken during a 30 second interval (a-d). Taxonomic assignment Various species names are applied in the literature to tropical West African Mecistocephalus, among them such classical names as M. maxillaris (Gervais, 1837), M. punctifrons Newport, 1843, and M. insularis (Lucas, 1863). However, observations on collections and literature surveyed by L.B. indicate that a single morphologically recognisable species of Mecistocephalus is widely distributed throughout most parts of the Afrotropics, including Cameroon, and it is correctly identi ed as Mecistocephalus togensis (Cook, 1896). e morphology of this species has been well illustrated (as Lamnonyx punctifrons) by Ribaut (1914). e following characters detected in the adult specimen allowed us to con dently assign it to Mecistocephalus togensis: cephalic plate 1.55 times as long as wide; areolate part of the clypeus about as long as the plagulae; cephalic pleurites bearing setae only on their posterior part; forcipular coxosternal cerrus featuring as a pair of broad bands of setae; no dark patches along the trunk; and a total number of 49 pairs of legs. e combination of these characters permits distinction of M. togensis from all other species with which it has been repeatedly misunderstood (including M. maxillaris, M. puncti- Brooding in Mecistocephalus 143 frons and M. insularis; see Bonato & Minelli 2004 and Bonato et al. 2009, for revised descriptions and discussions on the identity of these species), as well as from other congeneric species known to occur in other parts of the African continent (especially M. guildingii Newport, 1843 from western coastal regions; Bonato et al. 2009). Discussion Unlike the situation in Dicellophilus carniolensis in which multiple observations have been made on broods and the same posture is seen by di erent mothers when guarding either eggs or hatchlings (Bonato & Minelli 2002 and a few other subsequent records by L.B.), brooding in Mecistocephalus togensis is known from a single instance, and is limited to knowledge of post-embryonic guarding only. We do not yet know whether or not M. togensis maintains this posture through the full period of parental care; the data for D. carniolensis allow a reasonably con dent inference that brooding posture does not change. Likewise, we cannot evaluate whether or not the behaviour of the Cameroon brood of Mecistocephalus togensis is typical for the species, or instead variable between specimens, nor whether it is more broadly shared with other members of Mecistocephalus or other mecistocephalid genera. ose caveats noted, the fact stands that for at least some part of the brooding phase in some mecistocephalids, a posture otherwise known only in Adesmata is seen. is is the rst indication of homoplasy in this character in Phylactometria; brooding posture had previously t the widely accepted cladogram with complete consistency, with the dorsal surface inward orientation having a single evolutionary gain in Adesmata from ancestors that brooded with the ventral surface inwards. Assuming the sister group relationship between Placodesmata and Adesmata (as had been defended by both morphological and molecular data before and independently of the discovery of Dicellophilus broods), and the monophyly of Mecistocephalidae (a result supported in published analyses; Bonato et al. 2003), the new data from Mecistocephalus allow for the possibility that “dorsal surface inwards” could be convergent in Mecistocephalus and Adesmata, or that the general condition in Geophilomorpha is brooding with the dorsal surface inwards and Dicellophilus exhibits a reversal to the primitive state for Phylactometria as a whole. e data at hand do not permit a choice between these equally parsimonious optimisations. Additional observations on brooding posture in Mecistocephalidae, and indeed more geophilomorph diversity, are needed. Acknowledgements G.G. was assisted in the eld by Ligia Benavides, Gonwouo Nono Legrand, and Jerome Murienne. Fieldwork in Cameroon was supported by a Putnam Expedition Grant from the Museum of Comparative Zoology and collecting permits were facilitated by G.N. Legrand. 144 Gregory D. Edgecombe et al. / International Journal of Myriapodology 3 (2010) 139-144 References Arthur, W. & Chipman, A.D. (2005) e centipede Strigamia maritima: what it can tell us about the development and evolution of segmentation. – BioEssays 27: 653-660. Bonato, L., Cupul-Magaña, F.G. & Minelli, A. (2009) Mecistocephalus guildingii Newport, 1843, a tropical centipede with amphi-Atlantic distribution (Chilopoda: Geophilomorpha). – Zootaxa 2271: 27-42. Bonato, L., Foddai, D. & Minelli, A. (2003) Evolutionary trends and patterns in centipede segment number based on a cladistic analysis of Mecistocephalidae (Chilopoda: Geophilomorpha). – Systematic Entomology 28: 539-579. Bonato, L. & Minelli, A. (2002) Parental care in Dicellophilus carniolensis (C. L. Koch, 1847): new behavioural evidence with implications for the higher level phylogeny of centipedes (Chilopoda). – Zoologischer Anzeiger 241: 193-198. Bonato, L. & Minelli, A. (2004) e centipede genus Mecistocephalus Newport 1843 in the Indian Peninsula (Chilopoda Geophilomorpha Mecistocephalidae). – Tropical Zoology 17: 15-63. Chao, J.L. (2008) Scolopendromorpha (Chilopoda) of Taiwan. Collection, Description, Illustration, Taxonomy, Distribution. VDM Verlag Dr. Müller, Saarbrücken, 95 pp. Coscarón, S. & Ferrariis, O. de (1963) Observaciones sobre el cuidado de los huevos y crías en Cormocephalus (Hemiscolopendra) laevigatus Porat (Chilopoda-Scolopendridae). – Revista de la Sociedad Entomológica Argentina 24: 67-69. Dohle, W. (1985) Phylogenetic pathways in the Chilopoda. – Bijdragen tot de Dierkunde 55: 55-66. Edgecombe, G.D. & Giribet, G. (2002) Myriapod phylogeny and the relationships of Chilopo- da. – In: Llorente Bousquets, J. & Morrone, J.J. (eds.) Biodiversidad, taxonomía y biogeograa de artrópodos de México: hacia una síntesis de su conocimiento, volumen III. Prensas de Ciencias, Universidad Nacional Autónoma de México, México, pp. 143-168. Edgecombe, G.D. & Giribet, G. (2004) Adding mitochondrial sequence data (16S rRNA and cytochrome c oxidase subunit I) to the phylogeny of centipedes (Myriapoda, Chilopoda): an analysis of morphology and four molecular loci. – Journal of Zoological Systematics and Evolutionary Research 42: 89-134. Edgecombe, G.D., Giribet, G. & Wheeler, W.C. (1999) Phylogeny of Chilopoda: Combining 18S and 28S rRNA sequences and morphology. – In: Melic, A., de Haro, J.J., Mendez, M. & Ribera, I. (eds.) Evolución y Filogenia de Arthropoda. Boletín de la Sociedad Entomológica Aragonesa 26: 293-331. Foddai, D. & Minelli, A. (2000) Phylogeny of geophilomorph centipedes: old wisdom and new insights from morphology. – Fragmenta Faunistica, Warszawa 43: 61-71. Ribaut, H. (1914) Myriapodes I. Chilopoda. – Voyage de Ch. Alluaud et R. Jeannel en Afrique oriental (1911-1912). Resultats scienti ques, pp. 1-35. A. Schulz, Paris. Shelley, R.M. (2002) A synopsis of the North American centipedes of the order Scolopendromorpha (Chilopoda). – Virginia Museum of Natural History Memoir 5: 1-108. Turcato, A., Fusco, G. & Minelli, A. (1995) e sternal pore areas of geophilomorph centipedes (Chilopoda, Geophilomorpha). – Zoological Journal of the Linnean Society 115: 185-209. Verhoe , K.W. (1902-25) Chilopoda. – In: Bronn, H.G. (ed.) Klassen und Ordnungen des Tierreichs, 5, Abt. 2, Buch 1. Akademische Verlagsgesellschaft, Leipzig, p. 1-725.