Lamyctes mauriesi Demange, 1981

Popovici, George, Edgecombe, Gregory D. & Hall, Daniel W., 2024, New Chilopoda from the Chagos Archipelago, Journal of Natural History 58 (41 - 44), pp. 1885-1915 : 1892-1895

Lamyctes mauriesi Demange, 1981

( Figure 3 )

Material examined

6 ♀♀: NHMUK015558196 , DNA barcode voucher; NHMUK015619674 (5 ♀♀), Diego Garcia, 7.359°S, 72.432°E, leaf litter, 02 July 2022, leg . W . Rabitsch; 1 ♀, NHMUK015558199 , DNA barcode voucher, Diego Garcia, Plantation Gate closed, 7.411° S, 72.452°E, leaf litter, 23 June 2022, leg . W . Rabitsch.

Description

Habitus. Body length 4.8–5.5 mm (for specimens used as DNA barcode vouchers). Colour in ethanol: Cephalic shield and tergites uniformly dark brown, legs light brown with violet distal articles. No dark colouration around ocellus or anterior margin of cephalic shield.

Cephalic shield ( Figure 3 (A)). Frontal margin with evident medial notch, lacking a median furrow, ocellus present. Posterior margin of cephalic shield nearly transverse, with indistinct margination. Antenna with 32–34 articles, ca. 5 times longer than cephalic shield and about half of body length. Pairs of articles 3–4, (6)7–8, 11–12, 14–15, 17–18, 23– 24 and 26–27 relatively shortened.

Forcipular coxosternite. Subtrapezoidal with weak shoulder and gently converging lateral margin. Anterior margin with 2 + 2 teeth and a short, spinous pseudoporodont ( Figure 3 (B)). Pseudoporodont displaced proximally to teeth. Median diastema 1.5 times wider than the gap between teeth, with rounded apex. Long setae clustered near anterior margin and on the internal side of forcipular articles.

Trunk. All tergites with rounded posterior angles and without projections. Posterior margins weakly concave. Large tergites with complete posterior margination.

Legs. Distal spinous projection distinctly acuminate and present on tibiae 1–12 ( Figure 3 (C)). Legs 13–15 without projections. Ultimate legs up to 3 mm long (approx. 60% of body length). Tarsus 1 20% and tarsus 2 18.5% of its length ( Figure 3 (D)). All legs with anterior and posterior accessory claws, approximately 40% of the length of the apical claw. Coxal pores on legs 12–15 arranged as 2 + 2, 2(3) + 2(3), 2(3) + 3, 3 + 3 respectively.

Gonopods ( Figure 3 (E–G)). Female gonopods with 3 + 3 (rarely 2 + 3) spurs and simple claw. Article I with 7–9 setae, article II with 2–3 setae and article III with 1 seta.

COI barcode. GenBank accession numbers PQ165822 (NHMUK015558199), PQ165823 (NHMUK015558196).

Remarks. A possible synonymy with Lamyctes albipes ( Pocock, 1894) , originally described from Java, and L. mauriesi Demange, 1981 , originally described from Guadeloupe, was discussed by Eason and Enghoff (1992) and has generally been endorsed in recent studies (eg Akkari and Ganske 2018). Variability in number of antennal articles and number of spurs on the female gonopod has been a focus of discussion. Pocock’s type of L. albipes has 28 articles and 2 + 2 spurs on the gonopod ( Figure 4 (D)), but Attems (1907) assigned a specimen from Buitenzorg (Bogor), Java, with 33–34 articles and 3 + 3 spurs to that species. Demange (1981a) considered Attems’ specimen to be without doubt (‘sans doute’) a different species, which he compared to L. mauriesi . The holotype of L. mauriesi has 30 articles and 3 + 3 spurs. However, specimens from the Canary Islands that were confidently identified as L. mauriesi mostly show 2 + 2 spurs apart from two specimens with 3 + 2 or 2 + 3 ( Eason and Enghoff 1992). A female from the Karakaram Range in India or Pakistan assigned to L. albipes by Silvestri (1935) has 28 and 23 (the latter ‘certainly anomalous’) articles and 2 + 2 spurs. Eason (1996) assigned females from Sakhalin Island in the Russian Far East to L. albipes , matching Pocock’s type in having 28 articles and 2 + 2 spurs. Females assigned to L. albipes from the Seychelles ( Mahé, Silhouette, Praslin) have 30 antennal articles and 3 + 3 spurs ( Demange 1981b; Stoev and Gerlach 2010).

Specimens from Diego Garcia correspond most closely to the Javanese specimen assigned (likely incorrectly) to L. albipes by Attems (1907). A distal spinous projection is present on the tibia of leg 12 in Chagos specimens ( Figure 3 (C)), as in the Java specimen, but is lacking in the types of L. mauriesi and L. albipes , the latter having a weak, blunt projection ( Figure 4 (C)). The Chagos and Java specimens have the highest antennal article count of any material assigned to L. mauriesi or L. albipes (32–34 vs 28–30). With respect to L. albipes , L. albipes sensu Attems (1907) and L. mauriesi , the shape of the forcipular coxosternite and its anterior margin do not carry diagnostic information, with descriptions of these characters largely matching among all three species (compare Figure 3 (B) to Figure 4 (A,B)). Without molecular data for populations other than the Chagos Archipelago, we are unwilling to name additional species within what is likely to be a species complex and treat populations with 3 + 3 spurs on the female gonopod and 30 or more antennal articles as L. mauriesi .

Accepting a close affinity between L. mauriesi and L. albipes , this likely clade is known exclusively from females throughout its broad geographic range. These species are thus likely to be parthenogenetic like other Lamyctes species with cosmopolitan distributions, such as L. africanus and L. emarginatus (males are known only from limited parts of their ranges).

Figures

Figure 3. Lamyctes mauriesi Demange, 1981. (A–E) NHMUK015619674; (C–G) NHMUK NHMUK015619674. (A) Cephalic plate and antennae, dorsal view. (B) Anterior margin of forcipular coxosternite. (C) Distal end of tibia 12, lateral view, showing spinose projection. (D) Leg 15 (left side), lateral view. (E) Female gonopods, ventral view. (F–G) Female gonopods, ventral view. Abbreviations: md, median diastema; ppd, pseudoporodont.

Figure 4. Lamyctes albipes (Pocock, 1894). Holotype BMNH(E) 1896.10.6.7. (A) Forcipular segment, ventral view. (B) Anterior margin of forcipular coxosternite, ventral view. (C) Distal end of tibia of leg pair 12, lateral view, showing blunt projection. (D) Female gonopods, ventral view.