Rhicnosthetus chagasi, Bouzan & Iniesta & Brescovit, 2021

Bouzan, Rodrigo Salvador, Iniesta, Luiz Felipe Moretti & Brescovit, Antonio Domingos, 2021, Periclimenaeus djiboutensis Bruce 1970, Zoological Studies 60 (21), pp. 1-14 : 4-11

publication ID	https://doi.org/ 10.6620/ZS.2021.60-21
persistent identifier	https://treatment.plazi.org/id/6C19841C-FFC3-9C4B-FF5C-81487F62FE0E
treatment provided by	Felipe
scientific name	Rhicnosthetus chagasi
status

Treatment

Rhicnosthetus coriaceus ( Schubart, 1947) ( Figs. 4–5 View Fig View Fig , 11 View Fig )

Leptodesmus coriaceus Schubart, 1947: 11 View in CoL , figs. 10–11 (syntypes: 10 males, 10 females and 6 juveniles from Santa Terezinha, (-10.471803°; -50.515290°), formerly Barra do Tapirapé, Mato Grosso, Brazil, 23.XI.1939 − 15.III.1940, A. L. de Carvalho coll., deposited in MZSP and MNRJ). Only 2M and 2F deposited in MZSP, and 3M 2F deposited in MNRJ were examined (male lectotype, MNRJ 11812, and all remaining material as paralectotypes are here designated).

Rhicnosthetus coriaceus : Hoffman, 2006: 55, figs. 26–27.

Diagnosis: Males of R. coriaceus differ from all other species of the genus based on the combination of gonopodal characteristics: prefemoral process robust and reaching half the size of the acropodite ( Fig. 4a View Fig ) and acropodital process not exceeding the size of the solenomere ( Fig. 4d View Fig ).

Descriptive notes on females: (Paralectotype, MNRJ 11625). Pair of legs on body ring 3 with the coxae possessing a small process. Posterior margin of the vulvae aperture smooth, without projections ( Fig. 8b View Fig ). Vulvae rounded shaped in ventral view ( Fig. 5a View Fig ) and elliptical shaped in lateral view ( Fig. 5b View Fig ). Apical region with the intermediate membrane elevated ( Fig. 5d View Fig ) and medial region with a small aperture ( Fig. 5c View Fig ), ventral view. Total length: 55.41. Total width: 8.35. Posterior margin of the vulvae aperture: 1.59 width. Vulvae: length 0.75, width 0.50. External valve: length 0.62, width 0.32. Internal valve: length 0.48, width 0.24. Operculum: length 0.28, width 0.42. External valve (EV, Fig. 5a, 5d View Fig ) bigger; with long and scattered setae in comparison of the internal valve (IV, Fig. 5a, 5d View Fig ). Operculum large and densely covered by setae (OP, Fig. 5a–b View Fig ).

Distribution: Known only from the state of Mato Grosso, Brazil ( Fig. 11 View Fig ).

Rhicnosthetus chagasi sp. nov. ( Figs. 1–2 View Fig View Fig , 6–8 View Fig View Fig View Fig , 11 View Fig ) urn:lsid:zoobank.org:act:861C83D6-EBD8-445D-B56D-3FCCF84BFE47

Material examined: Male holotype and female paratype from Chácara dos Idosos, Cotriguaçu (-9.901695°; -58.570062°), Mato Grosso, Brazil, deposited in IBSP 7782 and IBSP 7783, respectively. Non-types: BRAZIL. Mato Grosso: Cotriguaçu (-9.901695°; -58.570062°), Chácara dos Idosos, no data and collector, Mato Grosso, Brazil, 2M and 1F (CZUFMT MYR 851); Fazenda São Nicolau, 13.XII.2009, L. D. Battirola coll., 4M and 3F (IBSP 5366).

Etymology: The specific epithet is a patronym in honor of Dr. Amazonas Chagas Júnior, for his friendship and several contributions to our knowledge of Myriapods in Brazil.

Diagnosis: Males of R. chagasi sp. nov. differ from all other species of the genus based on the combination of gonopodal characteristics: prefemoral process slender and reaching half the size of the acropodite ( Fig. 6d View Fig ) and a falciform acropodital process exceeding the size of the solenomere ( Fig. 6f View Fig ).

Description: Male (Holotype, IBSP 7782). Coloration in life: head reddish brown. Antennae with yellow and brown antennomeres. Body dark brown, with the paranota tip yellow ( Fig. 1 View Fig ); (long-preserved in 70% ethanol): Head ocher with the apex brown. Antennae yellowish. Body light brown and paranota tip yellowish ( Fig. 6a–c View Fig ). Body rings: cuticle with microgranular texture ( Fig. 2b View Fig ); paranota rectangular with posterior edges slightly produced ( Fig. 2a View Fig ); ozopore central-posteriorly situated on paranota ( Fig. 2a View Fig ). Stigma oval. Sternites with podosterna rough (= longitudinally striated – Hoffman, 2006) ( Fig. 2c View Fig ). Sternite of body ring 4 with a pair of small rounded projections appressed against each other. Sternite of all the body rings with two pairs of small rounded projections ( Fig. 2c View Fig ). Pair of legs on body ring 3 with coxae possessing a rectangular-shaped gonapophysis. Gonopod aperture on seventh body ring oval, posterior edge without any modifications. Legs yellowish, without modifications, with scattered thin setae ( Fig. 2d View Fig ). Telson with the same color as the body. Total length: 54.60. Total width: 8.04. Collum, length, 1.88, width, 6.81. Antennomere lengths (1> 7): 0.65; 1.39; 1.38; 1.43; 1.29; 1.37 0.35. Podomeres lengths (1> 7): 0.66; 0.95; 2.38; 0.77; 0.84; 1.47; 0.45. Gonopod aperture, length 0.94, width 1.81 Telson, length 1.57. Gonopod: length 2.11, width 1.72. Coxae: length 0.74, width 1.00. Telopodite: length 2.11, width 0.80.

Gonopods ( Figs. 6d–f View Fig , 7a–d View Fig ): coxae equivalent to about half the length of the telopodite and prominently rounded in ectal view ( Figs. 6f View Fig , 7c View Fig ). Coxae with two setae on the distal dorsal side. Presence of small spiniform process hidden by the coxa in mesal view (SP; Fig. 6d View Fig ). Cannula: hook-shaped. Prefemoral region long, 1/2 length of telopodite. Prefemoral process long and slim, with the apical region curved and reaching half the length of the acropodite (PfP; Figs. 6d View Fig , 7a View Fig ). Prefemoral process with a reduced small spine in the medial region of the process. Acropodite elongated and robust; composed of a large and concave lobe on dorsal side conducting the seminal groove along its edge (SG; Fig. 6d, f View Fig ); and distal and falciform acropodital process (AP; Fig. 6d, f View Fig ). Solenomere and acropodital process close to the apical region of the acropodite ( Fig. 6d–f View Fig ).

Female (Paratype, IBSP 7783). Body as in male. Pair of legs on body ring 3 with the coxae possessing a small, blunt process ( Fig. 8a View Fig ). Posterior margin of the vulvae aperture smooth, without projections ( Fig. 8b View Fig ). Vulvae rounded shaped in ventral view ( Fig. 8c View Fig ) and elliptical shaped in lateral view ( Fig. 8d View Fig ). Apical region with a large aperture ( Fig. 8f View Fig ) and medial region with a small aperture ( Fig. 8e View Fig ), ventral view. Total length: 54.72. Total width: 7.78. Posterior margin of the vulvae aperture: 1.73 width. Vulvae: length 0.77, width 0.573. External valve: length 0.51, width 0.24. Internal valve: length 0.54, width 0.18. Operculum: length 0.24, width 0.38. External valve (EV, Fig. 8c–d View Fig ) with long and scattered setae in comparison of the internal valve (IV, Fig. 8c–d View Fig ). Operculum large and densely covered by long setae; small setae restricted in the centro-apical part (OP, Fig. 8c–d View Fig ).

Distribution: The species is known from the region of Cotriguaçu, state of Mato Grosso, Brazil ( Fig. 11 View Fig ).

Rhicnosthetus penabarbosai sp. nov. ( Figs. 9–11 View Fig View Fig View Fig ) urn:lsid:zoobank.org:act:D500C918-01ED-40FF-9764-4937B79B1A7F

Material examined: Male holotype and male paratype from Chapada dos Parecis (-14.339394°; - 56.39202°), Diamantina, Mato Grosso, Brazil, XI.1993, D. Novaes & R. Pardini coll., deposited in IBSP 7784 and IBSP 7785, respectively.

Etymology: The specific epithet is a patronym in honor of Dr. João Paulo P. Pena Barbosa, for his outstanding contributions to our knowledge concerning the Chelodesmidae , and for his friendship and advice over the years.

Diagnosis: Males of R. penabarbosai sp. nov. differ from all other species of the genus by having the prefemoral process as long as the acropodite ( Figs. 9d– f View Fig , 10a–d View Fig ) and by having the solenomere and acropodital process divided at the base of the acropodital region ( Fig. 9e View Fig ).

Description: Male (Holotype, IBSP 7784). Coloration (long-preserved in 70% ethanol): Head ocher. Antennae yellowish ocher. Body ocher and paranota tip yellowish – not uniform throughout the body, probably due to ethanol depigmentation ( Fig. 9a–c View Fig ). Body rings: cuticle with microgranular texture; paranota rectangular with posterior edges slightly produced ( Fig. 9b View Fig ); ozopore central-posteriorly situated on paranota. Stigma oval. Sternites with podosterna smooth. Sternite of body ring 4 with a pair of small rounded projections appressed against each other. Sternite of all the body rings with two pairs of small rounded projections. Pair of legs on body ring 3 with coxae possessing a rectangular-shaped gonapophysis. Gonopod aperture on seventh body ring oval, posterior edge without any modifications. Legs yellowish ocher, without modifications, with scattered, thin setae. Telson with the same color as the body. Total length: 43.05. Total width: 6.04. Collum, length, 1.80, width, 5.70. Antennomere lengths (1> 7): 0.55; 1.31; 1.19; 1.05; 1.22; 1.21 0.25. Podomeres lengths (1> 7): 0.65; 0.75; 1.98; 0.63; 0.86; 1.23; 0.37. Gonopod aperture, length 0.74, width 1.35 Telson, length 1.16. Gonopod: length 1.66, width 1.27. Coxae: length 0.51, width 0.98. Telopodite: length 1.55, width 0.52.

Gonopods ( Figs. 9d–f View Fig , 10a–d View Fig ): coxae equivalent to about half the length of the telopodite and prominently rounded in ectal view ( Figs. 9f View Fig , 10c View Fig ). Coxae with two setae on the distal dorsal side. Presence of small spiniform process hidden by the coxae in mesal view (SP; Fig. 10a View Fig ). Cannula: hook-shaped. Prefemoral region long, 1/2 length of telopodite. Prefemoral process long and slender, with the apical region curved and as long as the solenomere (PfP; Fig. 9d–f View Fig ). With small spine in the medial region of the process. Acropodite elongated and slender in comparison with the other species of the genus; consisting of a reduced concave process without a lobe and conducting the seminal groove along its edge on dorsal side (SG; Fig. 10d View Fig ) and distal, slender and falciform acropodite process (AP; Figs. 9d–f View Fig , 10c–d View Fig ). Solenomere and acropodital process divided at the base of the acropodital region ( Fig. 9e View Fig ). Solenomere with a broad large apex ( Fig. 10b View Fig ).