Bactrurus cellulanus n. sp.
Figs. 23-25
Bactmrus sp.; Holsinger, 1986a: 95.
TYPEL OCALITY- . Small spring- or seep-fed
stream in unfinished basement of Jordan Hall on
campus of Indiana University, Bloomington
(Monroe County, Indiana).
MATERIAL
INDIANA-. Monroe Co.: seep-fed stream in basement of
Jordan Hall, Indiana University, Bloomington, 1 female
paratype (JRH), F. Young, XII- 1962; HOLOTYPE male
(15.8 mm, on two slide mounts; USNhl296422), and 1 male
paratype (JRH), 8-1-1963 (specimens collected by Young
donated to study by J. J. Lewis); allotype female (15.5 mm;
USNM acc. nr. 395927), N. Hynes,-1-1963.
DIAGNOSIS- . A medium-sized species morphologically very similar to B. wilsoni and B. angulus.
Bactrurus cellulanus can be distinguished by the following
characters: distal margin of right lacinia
mobilis with large, irregular denticles. Propods of
gnathopod 1 and 2 subequal in length, propod of
gnathopod 1 noticeably wider than propod of
gnathopod 2; defining angle of gnathopod 1 distinct
(ca. 140"). Pereopod 5 about as long as pereopod
4. Coxal gills on pereopods 2-7, distinctly
reduced on pereopod 7 (less than half the size of
coxal gill on pereopod 6). Two pairs of lateral
sternal processes on pereonites 6 and 7; median
sternal processes absent. Male uropod 1 with serrate
peduncular process. Telson of adult male
sometimes slightly longer than telson of female,
apical spines shorter than those of female; telson
with shallow notch or V-shaped excavation (5-
19% cleft). Largest male 15.8 mm, largest female
15.5 mm.
DESCRIPTION- .B ased on holotype male (15.8
mm; Figs. 23A-E, 24A, B, 25A-J) and allotype
female (15.5 mm; Fig. 25K, L).
Antenna 1 subequal to that of B. mucronatus, 60-
79% length of body. Primary flagellum with up to
47 segments.
Antenna 2 about 45-49% length of antenna 1
(Fig. 23A). Flagellum with up to 16 segments.
Lower lip subequal to that of B. wilsoni.
Mandibles (Fig. 23B): row of seven plumose
spines between molar and lacinia mobilis; distal
margin of right lacinia mobilis subequal to that of
B. wilsoni (with large, irregular denticles; see
enlargement Fig. 23B). Palp segment 2 with 13 to
14 setae on lateral and medial margins; palp segment
3 with 28 to 30 short, plumose D-setae,
three to five long, plumose B-setae and two to
four long, plumose A-seta.
Maxilla 1 subequal to that of B. wilsoni.
Maxilla 2 (Fig. 23C): outer plate apically with up
to 19 setae. Inner plate with oblique row of 10
strong, plumose setae and up to 19 plumose setae
apically and subapically.
Maxilliped: outer plate with four to five blade-like
spines and ca. 12 naked setae on inner margin
(Fig. 23D). Inner plate apically with four bladelike
spines and three to four plumose setae (Fig.
23E).
Gnathopod 1 (Fig. 24A): basis with approximately
18 long, naked setae on posterior margin, five plumose setae on posterodistal corner, seven to
eight naked setae on anterior margin and five
naked setae on medial surface. Carpus with two
rastellate spines on posterodistal margin (see
enlargement of Fig. 17B) and ca. six plumose
setae on distal margin. Propod noticeably wider
than propod of gnathopod 2 (but about equally
long); palmar margin almost even, crenulated,
armed with 15 to 17 spines on lateral margin and
about 2 1 spines on medial margin; defining angle
distinct (ca. 140°), bearing a row of five spines
medially and four spines on lateral corner; posterior
(subangular) margin 23% length of propod,
with four sets of plumose setae (distal set naked);
anteromedial surface bearing five rows of
plumose setae. Dactyl ca. 82% length of propod. Coxal plate with six setae.
Gnathopod 2 (Fig. 24B): basis with seven to nine
sets of long setae on posterior margin (with about
11 setae in total), four plumose setae on posterodistal
corner, three long, naked setae on
anteroproximal margin, five to six naked setae on
anterodistaI margin and six setae on medial surface.
Carpus with six sets of plumose setae on
posterior margin, five to six plumose setae on distal
margin and four rastellate spines on posterodistal
corner (see enlargement of Fig. 17B).
Palm of propod almost even, crenulated, with 12
to 13 spines on lateral margin and about 14
spines on medial margin; defining angle rounded,
with row of four spines on lateral corner; medial
corner with row of four spines, accompanied by
two long spines and one short spine; proximal
(subangular) margin ca. 3 1 O/O length of propod,
bearing five sets of plumose setae; anteromedial
surface bearing six rows of plumose setae. Dactyl
76% length of propod. Coxal plate wider than
long, bearing five to seven setae.
Pereopod 3 (Fig. 25A): basis with six long setae
and two short setae on posterior margin, five to
seven short setae on anterior margin and four to
seven long setae on anteroproximal margin and
surface. Coxal plate with to 10 to 11 marginal
setae.
Pereopod 4: subequal to pereopod 3. Coxal plate
with 11 marginal setae (Fig. 25D).
Pereopod 5 (Fig. 25B): anterior margin of basis
with nine short spines; posterior margin with 15
short setae. Coxal plate with four to five setae on
anterodistal lobe and two setae on posterodistal
corner.
Pereopods 6 and 7 subequal. Anterior margins of
bases with six to eight short spines; posterior margins
bearing up to 16 setae (including two to three
slender spines). Coxal plate of pereopod 6 with
two setae on posterodistal lobe (Fig. 25E). Coxal
plate of pereopod 7 with four setae on posterior
margin (Fig. 25C).
Coxal gills on pereopods 2-7, distinctly reduced
on pereopod 7 (less than half the size of coxal gill
on pereopod 6; Fig. 25C). Lateral sternal processes
present on pereonites 6 and 7 (Figs. 25C, E).
Pleopods: width of peduncles gradually increasing
from pleopod 1-3. Number of unfused rami
segments: pleopod 1 with nine to fifteen segments,
pleopod 2 with 12 to 14 segments and
pleopod 3 with eight to twelve segments.
Retinaculae reduced, asymmetrical (Fig. 25F).
Epimeral plates: posterodistal margins with five
to seven short setae each; plate 1 without spines,
plates 2 and 3 bearing three spines, respectively.
Uropod 1 (Fig. 25G): peduncle with 12 spines on
laterodorsal margin, four to five spines on
mediodorsal margin and four spines on mediodistal
corner. Rami about 62% length of peduncle;
inner ramus with five apical spines and about
eight to nine spines on dorsal surface. Outer
ramus with five apical spines and eight to ten
spines on dorsal surface. Peduncle of male with
ventrodistal, serrate process.
Uropod 2 (Fig. 25H): peduncle with three to five
spines on laterodorsal margin, one spine on
mediodorsal margin (sometimes absent) and two
to four spines on mediodistal corner. Inner ramus
longer than outer ramus, about 71°/o of length
peduncle, bearing four apical spines and seven to
eleven spines on dorsal surface (some of which
relatively long). Outer ramus with five apical
spines and five to seven spines on dorsal surface.
Uropod 3 (Fig. 251, K): peduncle armed with
three spines on distal margin. Inner ramus vestigial,
24-25% length of outer ramus (sometimes
with one tiny apical seta). Outer ramus reduced
(but relatively long), 80- 10 1 O/O length of peduncle,
bearing three to five apical spines, two to five subapical
spines on lateral margin and two to three
subapical spines on medial margin (sometimes
one spine on dorsal surface).
Telson (Figs. 255, L): width 90% of length. Apical
margin entire or with V-shaped excavation (15-
23% cleft), bearing 13 to 15 apical spines. Male
telson (Fig. 255) with relatively short apical spines;
spines distinctly longer in female telson (Fig. 25L).
SEXUADLI MORPHISM AND VARIATIO-N S. imilar to
B. angulus, variation was found in the excavation
of the distal telsonic margin (one male with entire
margin, other specimens with V-shaped excavation
(1 5-23 % cleft)). Secondary sexual dimorphism
occurred as described in uropod 1 and telson.
REMARK-S T.he type-locality is a small spring- or
seep-fed stream in an unfinished basement
beneath Jordan Hall on the campus of Indiana
University. The terrain surrounding the seep is karst developed on Mississippian-aged limestone
and is believed to have been a sinkhole complex
prior to construction of Jordan Hall. Four specimens
of the new species were collected in
December 1962 and January 1963, but Bactrurus
was not seen on a visit to the seep by JRH in June
1965. More recently, the diversion of the small
stream and other work in the basement has
apparently destroyed the type-locality 0. J. Lewis,
pers. corn.).
In addition to B. cellulanus, stygobiont
amphipods (Crangonyx packardz) and isopods
(Caecidotea jordanz), and an epigean crayfish
(Cambarus) have been collected from the seep-fed
stream beneath Jordan Hall.
Bactrurus cellulanus is morphologically closely
allied with B. wilsoni and B. angulus. Like the last
two species, B. cellulanus has a serrate peduncular
process on the male uropod 1. It can be further
distinguished as follows: inner plate of maxilla 2
with oblique row of 10 strong, plumose setae (six
to seven in most other species); outer ramus of
uropod 3 relatively long, bearing several subapical
spines on both margins; peduncle of uropod 3
armed with three distal spines (usually one to two
spines in other species).
Bactrurus cellulanus differs from B. angulus by the
following characters: 2 1 medial and 15 to 17 lateral
spines on palmar margin of gnathopod 1
(nine to ten medial and eight lateral spines in B.
angulus); defining angle of propod on gnathopod
1 less distinct; rami of uropod 1 with eight to ten
spines on dorsal surface (six spines in B. angulus);
dorsal margins of inner ramus on uropod with
seven to eleven spines, some of which relatively
long (five spines in B. angulus).
B. cellulanus can be distinguished from B. wilsoni
as follows: outer plate of maxilliped with four to
five blade-like spines (two to three in B. wilsonz);
posterior margin of carpus on gnathopod 2 with
six sets of plumose setae (three sets in B. wilsonz);
proximal, subangular margin of propod on
gnathopod 1 with four rows of plumose setae (less
setose in B. wilsonz); anterior margin of basis on
pereopod 5 with ca. nine short spines (six relatively
long, slender spines in B. wilsonz); coxal gill
of pereopod 7 less than half the size of coxal gill
on pereopod 6 (only slightly reduced in B. wilsonz);
mediodorsal margin of peduncle on uropod 1
with four to five spines (one spine or absent in B.
wilsonz); dorsal margins of inner ramus on uropod
with seven to eleven spines, some of which relatively
long (four to five spines in B. wilsonz).
ETYMOLOGY- .T he epithet cellulanus (Latin for
'hermit' or 'recluse') refers to the 'reclusive' habitat
in the basement of Jordan Hall, Indiana
University.
Source:
www.tiho-hannover.de/botanik/koenemann/bactrurus01.pdf
